Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
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Perspectives in Plant Ecology, Evolution and Systematics
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Biological Flora of Central Europe
Biological flora of Central Europe: Leucojum aestivum L.
Gilberto Parolo a,∗ , Thomas Abeli a , Graziano Rossi a , Giuseppina Dowgiallo b , Diethart Matthies c
a
Department of Earth and Environmental Sciences, University of Pavia, Via S. Epifanio 14, I-27100 Pavia, Italy
Department of Biologia Vegetale, University of Rome, La Sapienza, Piazzale Aldo Moro 1, I-00185 Roma, Italy
c
Department of Ecology, Faculty of Biology, Philipps-University, Marburg D-35032, Germany
b
a r t i c l e
i n f o
Article history:
Received 14 September 2010
Received in revised form 5 April 2011
Accepted 18 May 2011
Keywords:
Conservation status
Density effects
Ecological niche
Population size
Reproductive biology
Seed germination
a b s t r a c t
Leucojum aestivum L. (Amaryllidaceae) is a polycarpic C-S-European/W-Asiatic geophyte. It is a threatened
wetland species and is protected in several European countries, as a consequence of the destruction or
alteration of its habitats across Europe and the harvesting of its bulbs for medical purposes (alkaloids).
This paper deals with the taxonomic status, morphology, distribution, ecology and population biology of
this species, with special emphasis on habitat requirements, reproductive biology, and seed germination.
A detailed study in N-Italy found that L. aestivum grows on alluvial soils with high nitrogen levels. The
mean size of the plants increased with the water content of the soil. Similarly, within the habitats, the
water and nitrogen contents of the soil were higher in plots with L. aestivum than in those without the
species. Seed set of the plants was not influenced by the size of a population, but strongly increased with
the density of flowering plants. This was due to a decrease in the proportion of unfertilised eggs, indicating
pollen limitation of reproduction in low-density populations. Germination tests revealed that the optimal
germination temperature is between 20 ◦ C and 25 ◦ C.
© 2011 Perspectives in Plant Ecology, Evolution and Systematics. Published by Elsevier GmbH. All
rights reserved.
Taxonomy and morphology
Leucojum aestivum L. Sp. Pl. 1: 289 (1753); Gen. Pl. ed. 5:
140 (1754). (Amaryllidaceae) – Sommer-Knotenblume, Summer
Snowflake, Snowflake Lily, Loddon Lily, Campanellino estivo, Campanilla de Primavera, Copo de nieve.
L. aestivum subsp. aestivum
=Nivaria monodelphia Medic. 1790. Act. Acad. Theod. Palat. Phys. VI: 422.
=Polyanthemum aestivale Bubani 1902. Fl. Pyr. 4: 155. (nom. illeg.)
L. aestivum subsp. pulchellum (Salisb.) Briq. 1910 Prodr. Fl. Corse 1: 323.
=L. pulchellum Salisb. 1807. Parad. Lond. t 74.
=L. hernandezii Cambess. 1827. Mem. Mus. Par. XIV: 315.
=L. hernandezianum Schultes & Schultes fil. in Roemer & Schultes 1829,
Syst. Veg. ed. 15, 7(2): 784.
Taxonomy
Molecular studies have suggested that the genus Leucojum is
closely related to Galanthus L. (Meerow et al., 1999; Ito et al., 1999;
Lledó et al., 2004; Table 1). This hypothesis was first formulated by
Stern (1956), who located the origin of the common ancestor of the
∗ Corresponding author at: Dep. Earth and Environmental Sciences, University of
Pavia, Via S. Epifanio 14, I-27100 Pavia, Italy. Tel.: +39 0382 984854;
fax: +39 0382 34240.
E-mail address: gilberto.parolo@unipv.it (G. Parolo).
two genera in the Mediterranean area or in Central Europe. Meerow
et al. (2006) suggested that North Africa and the Iberian Peninsula
are the most likely areas of origin of this clade. In contrast, based
on cytological studies, D’Amato and Bianchi (1999) had found no
evidence for a common origin of the two genera.
The genus Leucojum consists of 11 species, belonging to four
groups or subgenera (Table 2). L. aestivum is the only species of the
subgenus Aerosperma (Baker, 1888; Contandriopoulos, 1962). Like
the subgenus Leucojum that includes only L. vernum L., the subgenus Aerosperma is characterized by hollow scapes, wide leaves
and clavate styles. Taxa from both subgenera are diploids with
a base chromosome number of n = 11 (Lledó et al., 2004). Subgenus Ruminia (Parl.) Baker includes three narrow endemics: (1)
L. valentinum Pau from eastern Spain, whose records from Greece
in the literature are considered to be erroneous (Bareka et al., 2006;
Jordan-Pla et al., 2009); (2) L. nicaeense Ardoino from the Maritime
Alps of southern France and NW-Italy (Diadema et al., 2004; Conti
et al., 2005), and (3) Leucojum fabrei Quézel and Girerd (Diadema
et al., 2004) from Mount Ventoux in France. The subgenus Ruminia
is characterized by solid scapes, narrower leaves and filiform styles
(Lledó et al., 2004). The largest of the four subgenera is Acis (Salisb.) Baker (Lledó et al., 2004), which includes two Atlantic species,
L. trichophyllum Schousb., occurring from Portugal to the Atlantic
coast of Morocco and North Africa, and L. autumnale L., with a distribution overlapping that of the previous species and reaching also
Sicily and Sardinia (Conti et al., 2005). There are also three narrow
1433-8319/$ – see front matter © 2011 Perspectives in Plant Ecology, Evolution and Systematics. Published by Elsevier GmbH. All rights reserved.
doi:10.1016/j.ppees.2011.05.004
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G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
Table 1
Systematic position of Galanthus, Leucojum and related genera (after Lledó et al.,
2004).
the phenological isolation between submediterranean/continental
populations.
Following Traub (1970)
Following Müller-Doblies and
Müller-Doblies (1978)
Karyology
Intrafamily Amaryllidoidinae
Tribe Narcisseae
Stembergia
Narcissus
Tribe Galantheae
Lapiedra
Hannonia
Leucojum
Galanthus
Intrafamily Pancratioidinae
Tribe Pancratieae
Pancratium
Vagaria
Tribe Narcisseae
Subtribe Narcissineae
Stembergia
Narcissus
Subtribe Galanthinae
Leucojum
Galanthus
The chromosome number of L. aestivum is 2n = 22 (Barros-Neves,
1939). The same number was found by other authors for material
of different origin, e.g. Chiappini and Scrugli (1970), D’Amato and
Bianchi (1999), Senel et al. (2002), and Bareka et al. (2003). This
chromosome number is considered plesiomorphic for the Amaryllidaceae family, due to its occurrence in many tribes of the family
(Meerow et al., 1999). However, other chromosome numbers have
also been reported (Magulaev, 1986; Özhatay, 2002: 2n = 24; Dobeš
et al., 1997: 2n = 21, 22, 23, 24). L. aestivum has one long, paired
metacentric chromosome, one pair of medium subtelocentric chromosomes and ten pairs of acrocentric chromosomes, ranging in size
from 3.1 to 16.6 m (Bareka et al., 2003). The mean base karyotype
length is 89.65 m ± 2.9 and the symmetry index 32.47 (D’Amato
and Bianchi, 1999).
Tribe Pancratieae
Subtribe Pancratiinae
Pancratium
Vagaria
Hannonia
Subtribe Lapiedrinae
Lapiedra
Morphology and anatomy
endemics: one from Corsica (L. longifolium J. Gay ex Salisb.), one
from Sardinia and Corsica (L. roseum Mart.), and a third from North
Africa (L. tingitanum Baker) (Lledó et al., 2004; Conti et al., 2005). A
fourth species, endemic to W-Greece and S-Albania, is L. ionicum Kit
Tan, Mullaj, Sfikas and Strid, described by Tan et al. (2004). Recently,
Bareka et al. (2006) and Meerow et al. (2006) considered the subgenus Acis to be a separate genus. Characters distinguishing the
four subgenera are summarized in Table 2.
Two subspecies of L. aestivum are known: L. aestivum L. subsp.
aestivum and L. aestivum L. subsp. pulchellum (Salisb.) Briq. L. aestivum subsp. aestivum is a Linnaean species (Linnaeus, 1753), whose
holotype has not been designated yet (Jarvis, 2010). Loci classici are
“Pannonia, Hetruria, Monspelii, Austria” (Linnaeus, 1753). L. aestivum subsp. pulchellum was described by Salisbury (1807–1808),
probably based on a plant growing in a botanical garden in London,
since the material figured in its book Paradisus Londinensis came
from gardens in the Metropolis. However, to our best knowledge,
no further information is available about the typus specimen and
the locus classicus (Fred Rumsey, Natural History Museum London,
Odile Weber and Paul Wilkin, RBG Kew pers. comm.).
Most authors recognize the two subspecies as valid taxa (Tutin
et al., 1980; Conti et al., 2005), but some have considered the subsp.
pulchellum only as a Mediterranean variety of L. aestivum, and as
part of the variability of L. aestivum subsp. aestivum (Chiappini,
1964; Chiappini and Scrugli, 1970). We agree with Tutin et al.
(1980) and Conti et al. (2005) in considering these two subspecies
as valid taxa, on the basis of their different, but adjacent geographic distribution, and phenological and morphological features
(see morphology and anatomy). Since L. aestivum subsp. pulchellum
flowers 2–3 weeks earlier than the subsp. aestivum, differentiation of the two subspecies may have started as a consequence of
L. aestivum is a perennial bulbous geophyte (Fig. 1). The bulb is
sub-spherical (up to 6 cm in diameter), with a brown tunic (Tutin
et al., 1980), which helps the plant to survive in the summer dry
period; it contains the basal plate, fleshy scales, 1–4 shoots, and
sometimes lateral buds. Adult bulbs were found to be 10.7 ± 1.2 cm
below the soil surface (n = 10, Pavia, N-Italy). The bulb shows a
sympodial branching system, each unit of which is composed of
6–8 foliage leaves, and a lingulate scale, and terminates in an inflorescence (Mori et al., 1991). Rarely, we observed anomalous bulbs
developing one above the other and linked by a pulpy protuberance 4–6.5 cm long (see Gay, 1859). This appears to be a reaction
to a covering of the bulbs by sediments; in this case the bulb axis
elongates to bring it to the appropriate level. The root system is
not ramified and roots start to grow usually at the end of the
summer/beginning of autumn. Contractile roots, that can pull the
bulb deeper, are present only in subadult plants (about a third of
the roots); contractile roots are slightly thicker than normal roots
(about 2.5 mm thick). In N-Italy, 3-year old plants were found to
have 12 ± 4 roots (n = 12); the length of the root system of adult
plants was 14.5 ± 2.8 cm (n = 16). The radius of the root system was
9.6 ± 2.9 cm.
The leaves are broadly linear, amplexicaule with a lamina
10–110 cm long and 5–20 mm wide during the vegetation period;
the bases of foliage leaves, which encircle the axis and gradually enlarge, serve as a food storage organ (Mori et al., 1991). The
scape is stout, hollow, compressed with two serrulated hyaline
margins. The inflorescence is a single helicoidal cyme subtended
by a spathe formed of a single two-keeled leaf, with (1) 2–8 (11)
pendulous flowers. Each plant can produce up to 3 (4) flowering
scapes (or peduncles), but more commonly only one. Spatha bracts
Table 2
Characters distinguishing the four subgenera of Leucojum (modified from Lledó et al., 2004).
Subgenus
Scape
Longest floral pedicel
Perianth
Outer perianth
segment
Gynoecium
Length of
seed
Seed characters
Base chromosome
number
Leucojum
Aerosperma
Acis
Hollow
Hollow
Solid
Equal or longer than spathe
Equal or longer than spathe
Shorter than spathe
With spots
With spots
No spots
Callose-thickened
Callose-thickened
Apiculate or acute
5–7 mm
5–7 mm
1–3 mm
Pale
Black; no appendage
Greenish; no appendage
n = 11
n = 11
n = 7, 8
Ruminia
Solid
Shorter than spathe
No spots
Apiculate or acute
Style clavate
Style clavate
Style filiform;
unlobed
epigynousdisc
Style filiform;
unlobed epigynous
disc
1–3 mm
Greenish with appendage
n=9
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
321
A layer of papillous cells forms the tepal epidermis. Just below
it other cells, containing needle-shaped chloroplasts, occupy the
green parts of tepals. Chlorophyll concentration in the green parts
of tepals is fivefold lower than in the leaves (Ščepánková and
Hudák, 2004). L. aestivum is morphologically similar to L. vernum
from which it differs by its larger size, an inflorescence with more
than one flower, the dark coloured seeds lacking appendages, and
the adaptation to water dispersal (Lledó et al., 2004), instead of
myrmecochory (Servigne, 2008). Furthermore, L. aestivum flowers
generally a month later than L. vernum.
The differential characters of the two subspecies are: L. aestivum
subsp. pulchellum has leaves 5–12 mm broad, scape margin neither
denticulate, nor hyaline, bracts 30–50 × 4–6 (–7) mm, flowers 1–5,
tepals 8–15 mm long (Salisbury, 1807–1808); L. aestivum subsp.
aestivum has leaves 7–20 mm broad, bracts 30–50 × 7–11 mm,
flowers (1-)3-8(11), tepals 13–22 mm long.
Distribution and habitat requirements
Geographical distribution
Fig. 1. Morphology and anatomy of an adult plant of Leucojum aestivum subsp.
aestivum (longitudinal section).
2, fused entirely in one side, 3–5 cm long, 7–11 mm wide. Pedicels
are 2–7 cm long and the longest can exceed the spatha. The perianth
is formed by 3 + 3 tepals (2 whirls), 13–22 mm long, with a green
spot just below the apex. The style is slightly clavate and longer than
the 3 + 3 orange stamens (Tutin et al., 1980); the anthers dehisce
by terminal pores. The gynoecium is 3–14 mm long and contains
10–40 bitegmic crassinucleate ovules, supported by a marginalcentral placenta (Ekici and Dane, 2008). The fruit is a sub-spherical,
fleshy capsule 2–4 cm long and 1–2 cm wide. The seeds are large
(5–7 mm), black, spherical, without strophiole and with a spongy
testa which allows them to float (Tutin et al., 1980; Pignatti, 1982).
The moisture content of seeds has been determined as 33% (Çiçek
et al., 2007) and their mass as 94 mg (Çiçek et al., 2007) and 94.3 mg
(n = 405 seeds, own measurement).
The anatomy of leaves and tepals has been studied by
Ščepánková and Hudák (2004). The epidermis is covered by a
prominent cuticule and the mesophyll cells form a homogeneous parenchymatic tissue with many intercellular spaces a
typical feature of equifacial leaves. Leaves are amphistomatic, with
anomocytic stomata. The mesophyll cells are isodiametric with
chloroplasts along the cell walls. Leaves show some prominent
structures that are large central cavities filled with a mucose substance and separated by vascular bundles. Leaf chloroplasts have
an irregular, amoeboid shape and typical grana and stroma lamellae. A detailed description of the chloroplast of L. aestivum can be
found in Ščepánková and Hudák (2004).
Most of the Leucojum species are found in the western Mediterranean region. L. aestivum is a C-S-European/W-Asiatic species
whose distribution in the north reaches Ireland, Czechia and Slovakia, and in the east Turkey, the Crimea and Iran (Tutin et al., 1980;
Crellin, 2005; Fig. 2). The species occurs from sea level up to 350
(1000) m (Pignatti, 1982; Çiçek et al., 2007).
From the eastern to the western limit of its range, L. aestivum
subsp. aestivum occurs south of the Caspian Sea, in northern Iran
(Mazhari, 2004), a disjunction which shows that the plant distribution has been formerly broader; in the Caucasus in Azerbaijan
(Wendelbo, 1970) and in Georgia (Denk et al., 2001); in Turkey
(Kutbay and Kilinç, 1993; Ekici and Dane, 2008); in SW-Russia and
the Ukraine in Crimea (Marushevsky, 2003; Kohut et al., 2007), and
along the coast of the Black Sea (Tutin et al., 1980); in Bulgaria in the
Rhodope Mountains and along the Danube River (Stanilova et al.,
1994; Bondev, 1995; Gussev et al., 2003); in Hungary (Makra and
Zalatnai, 2006); in Romania and Moldova (Sârbu, 2007; Mardari
et al., 2009); in mainland Greece (Bergmeier, 1988; Arne Strid pers.
comm.; Schuler, 2007), Peloponnesos (Arne Strid pers. comm.) and
in some of the Greek islands (Bareka et al., 2003; Schuler, 2007;
Vladimirov et al., 2009); in Albania (Pinna et al., 2007), in Serbia
(Jovanović et al., 2009), Slovenia (Cater et al., 2001) and Croatia
(Čarni et al., 2004); in Slovakia and the Czech Republic (Somsak,
1992; Uherčíková, 1998); in Italy in the plain of the river Po, and
in Tuscany (Poldini, 1997; Conti et al., 2005; Parolo and Rossi,
2008); in Austria (Fischer et al., 2008); in France (Molinier and
Tallon, 1970; Guinochet and de Vilmorin, 1978; Aizpuru et al., 2001;
SILENE, 2006–2010); in Switzerland (Hess et al., 1967; Welten and
Sutter, 1982; Moser, 1999; Lauber and Wagner, 2000).
The rarer L. aestivum subsp. pulchellum is restricted to the Western Mediterranean region (Tutin et al., 1980). It grows in Italy,
in Sardinia (Chiappini and Scrugli, 1970; Pignatti, 1982; Conti
et al., 2005); in Corsica and in mainland France (Médail et al.,
1994; Moser, 1999; Frédéric Médail pers. comm.); in Spain on
the Balearic Islands of Mallorca and Menorca (Guinea Lopez and
Ceballos Jimenez, 1974; Bolòs and Vigo, 2001).
The subsp. aestivum also occurs, as an introduced plant, in
Belgium (Lambinon et al., 2004), in the Netherlands (Tutin et al.,
1980), and in Germany (Buxbaum, 1934; Oberdorfer, 2001). Populations of both L. aestivum subsp. aestivum and subsp. pulchellum
are known from the United Kingdom, but most of the populations
are derived from introduced plants (Stace, 2010). L. aestivum subsp.
aestivum is native only along the River Thames and its tributaries
(Farrell, 1979; Wigginton, 1999; Fred Rumsey, pers. comm.), where
322
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
Fig. 2. Distribution of Leucojum aestivum subsp. aestivum and L. aestivum subsp. pulchellum based on floristic literature and floristic databases (provided by Dr. E. Welk).
it reaches the northern limit of its natural range (Preston, 2007).
The subsp. pulchellum has been in cultivation in the U.K. for several centuries and much of the material now found in the wild in
Britain belong to this subspecies, escaped from cultivation or has
been deliberately planted (Fred Rumsey, pers. comm.). In Ireland L.
aestivum subsp. aestivum is considered to be native at a few sites.
However, also in Ireland many populations of both subspecies are
the result of past introductions (Farrell, 1979; Farrell, 1982). The
species is also naturalized or cultivated outside of its natural range
as an ornamental plant, e.g. in the USA (Straley and Utech, 2002),
Australia (George, 1987; Rippey et al., 2007), New Zealand (Healy
and Edgar, 1980), Japan (Mori et al., 1991a) and South America
(Hurrel and Delucchi, 2007).
Habitats
In the valley of the river Po (N-Italy), where most of the Italian populations of L. aestivum subsp. aestivum grow, winters are
relatively short, but foggy, spring and autumn are well marked,
while summers are generally hot and humid, but with little precipitation. In Britain L. aestivum grows in regions where the mean
January temperature is c. 4.3 ◦ C, the mean July temperature is c.
15.9 ◦ C, and mean annual precipitation reaches 811 mm (Hill et al.,
2004).
In its native distribution area L. aestivum subsp. aestivum occupies alluvial habitats near rivers, lakes or on the banks of canals,
and humid, often periodically flooded sites from 0 to 350 (1000) m
a.s.l., which are shaded, semi-shaded or in full light (Fitter, 1978;
Ellenberg, 1988; Oberdorfer, 2001; Zagorska et al., 1997; Čarni et al.,
2004). The soil of the habitats is usually sedimentary, deep and
compact, consisting of clay or loam, with a very fine texture and
hydrophilic character (Athanasiadis and Drossos, 1992; Stancic,
2005). It is rich in nitrate and humus and poor in carbonates, with
a moderately acid to slightly basic pH. L. aestivum occurs also far
from water bodies, but only where a sufficient amount of water in
the soil is available during the growing season from February to
the end of May; it never occurs in ruderal habitats as an early successional plant (Moser, 1999). In its habitats, the plant generally
occupies microdepressions, where soil moisture is higher (Stancic,
2005). Nevertheless, during summer the plant can be exposed to
drought, as a consequence of the lowering of the water level.
A detailed study of 26 populations of L. aestivum subsp. aestivum
in N-Italy found that the species was growing on alluvial soils, classified as Fluvisol (FAO, 1998). The soil characteristics were very
variable due to the highly variable nature and composition of the
fluvial deposits (Table 3). The mean size of plants in populations,
measured as maximum leaf length, increased with the water content of the soil (r = 0.52, F1,24 = 9.0, p < 0.01). At most sites silt was
the predominant soil fraction, but some sites had finer-textured
topsoils with a high proportion of clay (>40%), mainly associated
with wetland vegetation such as sedge and reed communities. The
variable composition of the sediments was also reflected in a wide
range of pH values (from acidic to nearly neutral) and of carbonate
contents (Table 3). The organic carbon contents and total N levels were high or very high at all sites with a few exceptions and
C/N ratios were rather low (mostly <10), indicating active mineralization processes (Duchaufour, 1995). Values of available P (P2 O5 )
were usually moderate to high (range 10–50 mg/kg); but at a few
sites very high P-levels were found, most likely due to crop fertil-
Table 3
Characteristics of the soil at 26 sites with Leucojum aestivum subsp. aestivum in
N-Italy. Soil samples were dried at 105 ◦ C for 24 h and sifted through a sieve of
2 mm mesh width. Physical–chemical analyses were performed following the MIPAF
(2000) standard protocol: pH was measured in a 1:2.5 soil/water suspension using
a glass electrode; organic carbon (C) by Walkley–Black wet combustion; organic
matter content was assessed as organic carbon times 1.726; total nitrogen (N) by
Kjeldahl digestion; total calcium carbonate (CaCO3 ) using a volumetric calcimeter;
particle-size distribution by the hydrometer method after a pre-treatment with
H2 O2 to eliminate the organic matter. Available phosphorous (P2 O5 ) was measured
colorimetrically after extraction with sodium bicarbonate (samples with pH >6.5)
or ammonium fluoride (samples with pH <6.5).
Variable
Mean
SD
Range
Sand (%)
Silt (%)
Clay (%)
pH
CaCO3 (%)
C (%)
Organic matter (%)
C/N-ratio
N (%)
P2 O5 (mg/kg)
Water content (%)
17.8
60.3
21.9
6.6
4.4
6.4
11.0
9.9
0.7
38.2
46.7
19.5
18.0
13.8
1.0
6.4
3.2
5.5
1.7
0.3
38.2
17
1.3–64.4
29.0–87.2
5.2–64.8
4.1–7.8
0–19.8
1.5–13.5
2.6–23.2
6.2–15.2
0.2–1.5
12.7–172.1
10.0–79.0
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
isation. These results are in broad agreement with the assessment
of the realised ecological niche of the species by Landolt (1977),
who classified L. aestivum as an indicator species for temporarily
moist, nutrient-rich soils with a pH of 5.5–8, and for half-shaded
conditions. In Central Europe the species is also an indicator of the
warmest habitats, which are wintermild with little risk of late frosts
(Landolt, 1977). Indicator values by Ellenberg et al., 2001 (indexes
vary from 1 to 9 or 12 for F index) are: L (light) = 7, T (temperature) = 8, K (continentality) = 4, F (humidity) = 9, R (soil reaction) = 7,
N (nutrients) = 8 and by Landolt (1977, indexes vary from 1 to 5) are:
F (humidity) = 4, R (soil reaction) = 3, N (nutrients) = 4, H (soil humus
content) = 4, D (soil dispersion) = 5, L (light) = 3, T (temperature) = 5,
C (continentality) = 2.
Very little is known about the habitats in which L. aestivum
subsp. pulchellum grows. It occurs in regions with a mediterranean
climate, characterized by warm to hot, dry summers and mild, wet
winters (Cowling et al., 1996), and as an introduced plant also
in regions with a temperate oceanic bioclimate (Rivas-Martinez
and Rivas-Sáenz, 2009). According to Guinea Lopez and Ceballos
Jimenez (1974) the species grows in mediterranean wet grasslands
and on river banks. In SE-France it occurs at altitudes of 0–100 m
and in Corsica of 0–300 m (Médail and Verlaque, 1997). In Mallorca it grows in mountain areas in Mediterranean Oak forests,
shrub vegetation of gravel beds of seasonal streams and in tall wet
grasslands.
Plant communities
L. aestivum grows in wetland plant communities, such as wet
meadows, forests and scrubs in the lowland river floodplains
and valleys (Ellenberg and Klötzli, 1972; Horvat et al., 1974;
Tutin et al., 1980; Ellenberg, 1988; Somsak, 1992; Athanasiadis
and Drossos, 1992; Mucina et al., 1993a,b; Grabherr and Mucina,
1993; Oberdorfer, 2001; Kutbay et al., 1998; Moser, 1999; Cater
et al., 2001; Lazowski, 2001; Leonardi and Rossi, 2001; Makra
and Zalatnai, 2006; Čejka et al., 2008; Parolo and Rossi, 2008;
Onyshchenko, 2009). Table 4 gives a list of syntaxa in which L. aestivum occurs. The anthropogenic herbaceous plant communities in
which the plant grows often replace former woods, which were
adapted to inundations and seasonally high ground-water levels.
Bergmeier (1988) suggested that in Greece L. aestivum is a relict
species of former woods.
Extensive vegetation surveys in 116 small random plots
(2 m × 3 m) in 26 populations of L. aestivum subsp. aestivum in the
valley of the river Po in N-Italy revealed the following: In speciespoor reed communities (Phragmition), L. aestivum subsp. aestivum
can be common and sometimes dominant. It flowers before the
main development of the reeds, thus avoiding the strong competition of Phragmites australis. In sedge communities (Magnocaricion
elatae) L. aestivum is commonly associated with Carex elata, Carex
acutiformis, Carex riparia, Carex hirta, Lysimachia vulgaris, Lythrum
salicaria, Phalaris arundinacea. In wet meadows (Molinietalia) L. aestivum is often associated with Scirpus sylvaticus, Lotus pedunculatus,
Caltha palustris, Myosotis palustris, Mentha longifolia, L. vulgaris,
Filipendula ulmaria, Poa trivialis, Valeriana officinalis, Allium angulosum, Gratiola officinalis, Alopecurus utriculatus, Alopecurus pratensis,
Ranunculus repens, Carex otrubae, C. riparia, and Poa sylvicola. In
woods of Alnus glutinosa (Alnion glutinosae), L. aestivum can be
dominant in the herb layer, where it is frequently associated with
Thelypteris palustris, Humulus lupulus, Iris pseudacorus, Carex elata,
C. acutiformis, Galium palustre, and Lysimachia vulgaris; in the shrub
layer common species are Salix cinerea, Viburnum opalus, and Frangula alnus. In woods of Salix alba (Salicion albae) L. aestivum occurs
scattered and is commonly associated with C. elata, C. acutiformis,
Equisetum telmateja, Phalaris arundinacea, G. palustre, G. aparine,
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Table 4
The main plant communities in which L. aestivum grows.
1. Phragmition communis Koch 1926 [reeds in slow-mowing water]
2. Magnocaricion elatae Koch 1926 [tall sedge swamps]
2.1 Phalaridetum arundinaceae Libbert 31 (Balkans: Horvat et al., 1974)
2.2 Caricetum vulpino-ripariae (Balkans: Horvat et al., 1974)
2.2 Eleochari-Caricetum nutantis (Balkans: Horvat et al., 1974)
2.4 Caricetum gracilis-vulpinae (Horvat et al., 1974)
2.5 Cyperetum longi caricetosum acutiformis (ass. char., Horvat et al.,
1974)
3. Cirsio brachycephali-Bolboschoenion (Passarge, 1978) Mucina in Bal.-Tul.
et al. 1993
3.1 Bolboschoenetum maritimi Eggler 1933 (Balkans: Horvat et al., 1974)
4. Calthion R. Tx. 1937 em. Bal.-Tul. 1978 [C-European manured moist
meadows]
5. Cnidion Bal.-Tul. 1966 [subcontinental Cnidium meadows]
6. Molinion Koch 1926 (all. char., Horvat et al., 1974) [Molinia litter meadows]
6.1 Carex gracilis-Poa palustris plant community (Horvat et al., 1974)
6.2 Ventenato-Trifolietum pallidi (Horvat et al., 1974)
7. Deschampsion Horvat 1930 (all. char., Horvat et al., 1974)
[SE-European manured moist meadows]
7.1 Deschampsietum cespitosae (Horvat et al., 1974)
7.2 Oenantho silaifoliae-Alopecuretum pratensis (Horvat et al., 1974)
8. Arrhenatherion Koch 1926 [Oatgrass meadows]
8.1 Arrhenatheretum elatioris holcetosum lanati (N-Croatia: Horvat et al.,
1974)
8.2 Bromo-Cynosuretum cristati (NW-Bosnia: Horvat et al., 1974)
9. Trifolion resupinati K. Micevski 1957 (SE Europe: Horvat et al., 1974)
[submediterranean meadows with annual Trifolium species]
10. Convolvuletalia sepium R. Tx. 1950 em. Mucina 1992 [semi-shaded
nitrophilous riparianand lacustrine megaforb or climbing
hygrophilous communities]
11. Alnion glutinosae Malcuit 1929 [Alder swamp woods]
11.1 Carici elongatae-Alnetum glutinosae var. Leucojum aestivum (Slovenia:
Cater et al., 2001; Horvat et al., 1974).
12. Salicion albae Soó 1930 [Willow communities of lowland flood plains]
12.1 Salici-Populetum nigrae (ass. char., Danubian floodplain forests: Čejka
et al., 2008; Serbia: Horvat et al., 1974)
12.2 Salicetum albae-fragilis (ass. char., Hungary: Makra and Zalatnai, 2006)
12.3 Salicetum albo-triandrae (Serbia: Horvat et al., 1974)
12.4 Leucojo-Fraxinetum angustifoliae (ass. char., Horvat et al., 1974)
13. Carpinion betuli Issler 1931 [mixed Hornbeam woods]
14. Alnion incanae Pawlowski in Pawlowski et Wallisch 1928 [Alder and
broadleaved woodsof flood plains]
14.1 Fraxino pannonicae-Ulmetum (Ukraine: Onyschenko et al., 2009)
14.2 Fraxino angustifoliae-Alnetum glutinosae (Austria: Lazowski, 2001)
14.3 Leucojo-Fraxinetum parvifoliae (Greece: Athanasiadis and Drossos,
1992)
14.4 Querco-Ulmetum (Europe: Horvat et al., 1974)
14.5 Pruno-Fraxinetum (Horvat et al., 1974)
15. Populetalia albae Br.-Bl. 1931 [submediterranean White Poplar woods of
flood plains]
16. Alno-Quercion roboris Horvat 1950 [Oak-Ash forests of flood plains]
16.1 Euphorbio palustris-Crataegetum nigrae leucojetosum aestivi
(Croatia: Čarni et al., 2004)
16.2 Genisto-Quercetum roboris (ass. char., Horvat et al., 1974)
17. Ostryo-Carpinion orientalis Horvat 1950 (SE Europe: Horvat et al., 1974)
[mixed deciduous and evergreen forests]
18. Quercion ilicis Br.-Bl. (1931) 1936 [Mediterranean Oak forests]
18.1 Cyclamini-Quercetum ilicis Alzinar. O.Bolós et R. Mol. 1908 (Mallorca).
19. Nerion oleandri Br.-Bl. et Bolos 1956 [Mediterranean shrub vegetation of
gravel beds of seasonal streams]
20. Molinio-Holoschenion Br.-Bl. ex Tchou 1948 [Mediterranean tall humid
grasslands]
Iris pseudacorus, L. salicaria, Rubus caesius, and Urtica dioica. In elmoak woods (Carpinion betuli), L. aestivum is not abundant, probably
because in these communities the water-table is not high enough.
L. aestivum frequently occurs in non-native Amorpha fruticosa shrub
communities, or in nitrophilous communities along river banks
(Convolvuletalia sepium R. Tx. 1950 em. Mucina 1993a) with Rubus
caesius, Urtica doica, Solidago gigantea, Phalaris arundinacea, Poa
trivialis, and R. repens; it can also rarely be found in woods of Populus
alba, and in plantations of Platanus hybrida.
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According to the European “Habitats Directive” 92/43/ECC, in
Sites of Community Importance L. aestivum can occur in the following habitats of the annex I of the directive (European Commision,
2007):
6410 Molinia meadows on calcareous, peaty or clay-silt-rich soils
(Molinion caeruleae);
6430 Hydrophilous tall herb fringe communities of plains and of
the montane to alpine levels;
6440 Alluvial meadows of river valleys of the Cnidion dubii;
9160 Sub-Atlantic and Central-European oak or oakhornbeam
forests of the Carpinion betuli;
91E0 Alluvial forests with Alnus glutinosa and Fraxinus excelsior
(Alno-Padion, Alnion incanae, Salicion albae) (priority habitat);
91F0 Riparian mixed forests of Quercus robur, Ulmus laevis and
Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the
great rivers (Ulmenion minoris).
Life cycle, phenology and growth
Seedlings of L. aestivum grow c. 1 cm in height in the first month
and c. 2.5 cm in the second month. Seedlings and young plants can
be easily recognized as they have only one or two leaves of 2–5 mm
width until the second year. Plants stay in the subadult age class
from 2 to 5/6 years, before they become adult flowering plants.
Little is known about the longevity of the species, but Zagorska
et al. (1997) recorded bulb aggregates older than 15 years, and
plants have survived for more than 50 years in the botanical garden
of the University of Halle, Germany (E. Jäger, pers. comm.). The bulbs
may produce lateral daughter bulbs which remain attached to the
mother bulb (Fig. 3), forming an aggregate of ramets. Each new
ramet can reach the flowering stage. Up to four shoots can develop
from a single bulb, growing inside the sheath of the mother plant
(Fig. 4).
In the plain of the river Po the ontogenetic cycle of L. aestivum lasts from October to June (Rossi and Dominione, 2005).
Seeds of L. aestivum germinate in autumn (as in Germany; Irmisch,
1860), when soil and air humidity increase after the dry summer
period. The epicotyl continues to grow slowly between January
Fig. 3. Vegetative propagation in L. aestivum: the short underground caulis can
generate new lateral bulbs that remain attached to the mother bulb.
and February (Leonardi and Rossi, 2001; Çiçek et al., 2007). Shoots
develop underground and emerge only when conditions become
milder (Davis, 1966); long sheathing leaves appear aboveground
in autumn, but foliage leaves start to develop in February–March.
Inflorescences develop from February to March and the flowers
open from late February to May, depending mostly on latitude
(Guinea Lopez and Ceballos Jimenez, 1974). Fruits mature from
May to June. After fruiting the leaves die off and the plant stays dormant until autumn. The subspecies pulchellum flowers 3–4 weeks
earlier than the subspecies aestivum (Salisbury, 1807–1808; Tutin
et al., 1980), probably due to the warmer climate of the Mediterranean Basin, where this subspecies occurs. Rarely, it can flower in
December (Bolòs and Vigo, 2001).
Spatial distribution of plants within populations
The spatial distribution of L. aestivum plants within populations
is influenced both by the ecological features of the micro-sites and
by clonal growth. Within a population microsites with L. aestivum
subsp. aestivum present are characterized by a significantly higher
water content (48.1% vs. 44.7%, F1,165 = 4.5, p < 0.05), a lower dry
matter content of sand (17.6% vs. 22.3%, F1,165 = 7.6, p < 0.01), but a
higher of silt (59.7% vs. 55.6%, F1,165 = 8.2, p < 0.01), and a higher
soil nitrogen content (0.55% vs. 0.49%, F1,165 = 5.0, p < 0.01) than
microsites without the plant. Moreover, as a result of vegetative
propagation plants usually grow in clumps and the spatial distribution is highly aggregated. Groups consisting of 10–20 bulbs can
be formed from one initial bulb within 12–15 years (Zagorska et al.,
1997). The density of plants can be very high (>1000 per m2 ), but is
usually much lower. In the Po Plain some populations in 2007 consisted of more than 30,000 flowering scapes, while others consisted
of a single flowering individual. Very small populations are common towards the margins of the range of the species (e.g. Greece,
Bareka et al., 2003; Switzerland, Hess et al., 1967; France, Frédéric
Médail, pers. comm.).
Reproduction
L. aestivum is a polycarpic species, whose flowers are pollinated
by insects. Potential pollinators are long-tongued nocturnal Lepidoptera, diurnal Lepidoptera (Vanessa urticae) and Hymenoptera,
Fig. 4. Shoots developing from a single basal caulis that remain included in the
sheath of the mother plant.
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G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
60
1.0
50
Chi2 = 2008.4
0.8
r = 0.74
P < 0.01
Seed set (%)
Probability of flowering
p < 0.001
0.6
0.4
40
30
0.2
20
0.0
0
20
40
60
80
100
1
120
2
20
50
100
200
Fig. 6. The influence of the mean density of flowering shoots per m2 on seed set in
populations of L. aestivum in the valley of the river Po in N-Italy.
influenced by soil water availability at the time of seed ripening.
The fruits are large and their weight bends the scape until the
fruits lie on the ground. Between flowering and fruit maturation
the scapes increase their length by up to a third, reaching a length
of 92.7 ± 2.1 cm (n = 37). This could be interpreted as a means of
dispersal to place the large and heavy seeds away from the mother
plant. River water during flooding events may be an important
means of dispersal, since fruits float on water and can thus be
carried over long distances (Phillips and Rix, 1991). Fruits mature
at the end of spring when the main European rivers, as a consequence of snow melting in the mountains, increase their flow and
occasionally flood.
160
140
Seed mass (mg)
such as bees (e.g. Anthophora pilipes, spring flower bee; Knuth,
1898–1904), Xylocopa violacea, and bumblebees. The flowers were
observed to function as shelters for several species of beetles
and spiders. Pollen is produced from 7 am to 6 pm (c. 0.1 mg per
flower and day) and anthers dehisce over a period of 1–8 days
(Percival, 1955). L. aestivum is self-incompatible (Knuth, 1909 and
own observ.) and there is no apomixis. In N-Italy, most plants
remain vegetative. Of more than 8000 plants studied, 30% flowered. Most flowering plants produce only a single flowering scape.
In N-Italy, 82% of plants produced one flowering scape, 17% two
scapes and only 1% three scapes. Each flowering scape produced
on average 4.52 (±0.02) flowers (range 1–11), while total flowers
of a plant were on average 5.47 ± 0.05 flowers (range 1–22). The
probability of flowering increased with plant size (Fig. 5). In N-Italy
the flowering probability of plants with leaves of less than 43 cm
was 10%, while of those with leaves longer than 69 cm more than
50% flowered.
Seed formation was studied in 404 fruits belonging to different
plants in 20 populations in N-Italy. The mean number of ovules
per fruit was 11.0 ± 0.21 of which 33.8% ± 0.07 developed into ripe
seeds. This low seed set was mainly due to the large proportion of
ovules (57.5% ± 0.89%) that were not fertilised and did not develop
at all, and to a lesser degree to seeds that were aborted (8.7% ± 0.6).
The mean number of seeds per fruit was 6.33 (±0.14). Seed set
(22–57%) and thus the number of seeds per fruit (3.5–12.1) varied
strongly among populations. Seed set of L. aestivum was not influenced by population size (r = 0.27, p = 0.24), but increased strongly
with the density of flowering plants (Fig. 6). This was due to the
reduction in the proportion of unfertilised ovules with density
(r = −0.70, p < 0.01), while the proportion of seeds aborted was not
influenced by density (r = 0.01, p = 0.99). This indicates that in L. aestivum reproduction is pollen limited in low-density populations. A
similar behaviour was found by Diadema et al. (2004) for the related
L. fabrei, a species endemic to France. Mean seed mass of L. aestivum varied strongly among populations, from 76 mg to 150 mg.
It was not influenced by population size (r = −0.30, p = 0.21) or
density (r = −0.14, p = 0.55), but increased strongly with the water
content of the soil (Fig. 7), suggesting that seed development is
10
2
Length of longest leaf (cm)
Fig. 5. Probability of flowering as a function of plant size (length of the longest leaf)
in L. aestivum. The line is the best fit of a logistic regression.
5
Flowering shoots per m
r2 = 0.51
p < 0.01
120
100
80
60
10
20
30
40
50
60
70
80
90
Soil water content (%)
Fig. 7. The relationship between mean seed mass and water content of the soil in
populations of L. aestivum in N-Italy. The line denotes a quadratic regression.
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Herbivores and pathogens
Fig. 8. Time course of germination of seeds of L. aestivum. The seeds were set to
germinate at 20 ◦ C for 150 days and then exposed to a typical course of temperatures
observed in the habitats of L. aestivum in N-Italy.
Seed germination
Collections of seeds were made at the time of natural dispersal
(late May) from 14 natural populations in the Po Plain (N-Italy). Few
days after collection, three replicates of 30 seeds for each population were sown on plain agar in 9 cm Petri dishes in the laboratory.
Treatments were incubated in temperature and light controlled
incubators using a 12 h daily photoperiod (4000 K, 20 W). Seed germination of L. aestivum depended strongly on temperature. After
100 days at 10 ◦ C and 15 ◦ C, no seeds had germinated. After the temperature had been increased to 20 ◦ C, seeds started to germinate c.
135 days after the start of the experiment, and after 260 days 75%
of the seeds had germinated. At 20 ◦ C, germination started after c.
40 days and reached 79% after 150 days (Fig. 8). Germination varied
strongly among populations (52–93%). Ungerminated seeds were
then exposed to a cycle of temperatures to simulate the annual temperature cycle in the Po plain (Ottone and Rossetti, 1980). However,
germination increased only at the end of this sequence, when seeds
were transferred from 25 ◦ C to 20 ◦ C, reaching 100% in some populations. Similar results were obtained by Çiçek et al. (2007) who
obtained 73% germination after 42 days at 22 ◦ C followed by 28
days at 20 ◦ C, but higher germination in a field experiment, where
temperatures were higher. Stratification of the seeds for 3–7 weeks
at 4 ◦ C induced dormancy (Çiçek et al., 2007).
This behaviour suggests that seeds of L. aestivum only germinate at higher temperatures (>15 ◦ C), which are common after seed
ripening in its area of distribution. However, summer drought could
represent a limiting factor for the germination of Leucojum in the
drier parts of its distribution. In Italy seedlings start to appear only
in September–October, although seeds ripen and are shed already
in June (Leonardi and Rossi, 2001).
Response to competition
L. aestivum subsp. aestivum can survive at a wide range of light
levels from heavy shade to full sunlight. Even quite low levels of
available light do apparently not reduce the vigour of the plants
much (Kutbay and Kilinç, 1993). The early growth and flowering
period avoid competition with most of the other plants of its habitats, mostly tall herbs such as Phragmites australis, Carex sp. pl., and
shrubs like Rubus caesius.
L. aestivum naturally produces some neurotoxic substances (see
also ‘Biochemical data’ section) as a means of defence against herbivores and pathogens (Wink, 2009). However, the plant is frequently
attacked by slugs and snails that eat scapes and fruits, mainly at
the beginning of June. This can strongly reduce the number of
seeds produced. In some large Italian populations, up to 100% of
the developing fruits were destroyed. Fruit predation is common
also in other species of Leucojum (Diadema et al., 2004). In some
Italian populations we also observed strong damage to the flowering scapes by nutrias (Myocastor coypus). According to the Royal
Horticultural Society (1996), larvae of the Narcissus Fly (Merodon
equestris Fabricius, Syrphidae) may damage L. aestivum by eating
bulbs.
Aecidium leucoji (Uredinales, Basidiomycota) is a pathogenic fungus specific to L. aestivum that attacks leaves and fruits (Saccardo,
1899). The fungus occurs on L. aestivum in its ecidial form, but the
reproductive form (Puccinia schmidtiana Dietel) is not known on L.
aestivum; it was reported by Saccardo (1899) only on the leaves
of P. arundinacea, a wetland plant species that grows frequently
together with L. aestivum.
The fungus is known for Europe since 1878 (Erb. Critt. Ital. ser.
II n. 99), and its presence was confirmed for Italy, Germany and
Hungary (Linhart, 1882). In the valley of the river Po, the fungus was
present in 11 of the 26 populations of L. aestivum subsp. aestivum
sampled in 2007. The probability of the presence of A. leucoji was
not influenced by the density (Chi2 = 0.08, p = 0.78) of a population
of L. aestivum, but large populations were more likely to be infested
than small ones (Chi2 = 2.78, p < 0.1). The fungus had, however, no
detectable influence on the performance and the reproduction of
L. aestivum (fruit set, seed set). It is not known whether A. leucoji
occurs also on L. aestivum subsp. pulchellum.
In a population of L. aestivum subsp. aestivum (Corteolona, in
the Province of Pavia, N-Italy), another fungus, Fusarium oxysporum
(Fr.) Schltdl. was found on the fruits of the plant, in close proximity
to A. leucoji. F. oxysporum, which has a world-wide distribution, is
known to provoke wilt and damping off of the plants, and it generally affects the plants after a primary fungal infection (Cummins,
1971), here probably by A. leucoji.
Systemic bulb infection represents a great obstacle to the micropropagation of L. aestivum and it is important to sterilize bulbs
collected from wild populations as soon as possible to control the
disease (Zagorska et al., 1997). Bulblets in the central part of the
main bulb are usually less infected (Zagorska et al., 1997).
Septoria malisorica Bubák is another pathogenous fungus which
can affect the leaves of L. aestivum (Saccardo, 1913).
Mycorrhiza
L. aestivum is usually associated with arbuscular mycorrhiza
(Harley and Harley, 1987).
Physiological data
The dormant bulbs of L. aestivum are fairly hardy and will withstand soil temperatures down to at least −5 ◦ C (Matthews, 1994).
Flower initiation occurs at any temperature from 10 to 30 ◦ C, but
the optimum temperature for flower initiation and further differentiation of floral organs is 20–25 ◦ C. In L. aestivum, further
development of flower buds after the carpel formation stage is
inhibited when plants are placed at or above 20 ◦ C (Mori et al.,
1991b). Anthesis is stimulated by temperatures between 10 ◦ C and
15 ◦ C (Mori et al., 1991b), and can occur at 100% of relative humid-
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
ity, but it is limited by temperatures lower than 7 ◦ C and rainy
weather (Percival, 1955).
Biochemical data
According to the International Plant Genetic Resources Institute L. aestivum is considered a Medicinal Plant (Baričevič et al.,
2004), containing several pharmaceutically important alkaloids
in its bulbs and leaves. These alkaloids are approved drugs for
the treatment of a limited number of patients suffering from
senile dementia of the Alzheimer type, poliomyelitis, alcohol and
nicotine dependence (Moorman, 1999) and other neurological diseases (Thomsen et al., 1991; Schwikkard and van Heerden, 2002;
Heinrich and Lee Teoh, 2004; Marco and do Carmo Carreiras,
2006). So far, about 20 alkaloids have been isolated from L. aestivum subsp. aestivum (Stefanov, 1990), belonging to five groups:
N-allylnorgalanthamine, galanthamine, epinorgalanthamine, narwedine, and lycorine (Berkov et al., 2008). The most important of
these are alkaloids of the galanthamine type, isoquinoline alkaloids
with an inhibition effect on acetylcholinesterase (Diop et al., 2007).
This inhibition is long-acting, selective, reversible, and competitive
and produces beneficial effects even after the drug treatment has
been terminated (Maelicke et al., 2001).
Galanthamines for medical applications can be produced synthetically (Küenburg et al., 1999), but the most important source
is bulbs of the Amaryllidaceae, such as Narcissus sp. pl. and Leucojum (Eichhorn et al., 1998). For this reason, bulbs of L. aestivum
are still collected on a large scale in natural populations, causing
the decline of the species (Çiçek et al., 2007). The alkaloid content of plants and the relative proportions of the main alkaloids
(galanthamine and lycorine) vary among populations (Georgieva
et al., 2007; Bogdanova et al., 2009) and depend on plant genotype
(Stanilova et al., 2009).
However, it has been demonstrated that L. aestivum has a high
regenerative potential that could be used for micro-propagation.
This kind of technique is increasingly applied to Leucojum (Girmen
and Zimmer, 1987; Pavlov et al., 2007; Georgiev et al., 2009). Tissue
and root hair culture has successfully yielded compounds identical
to the alkaloids from natural sources (Diop et al., 2007). Stanilova
et al. (1994) obtained about 630 plants from a single original plant
of L. aestivum. Leaves are more suitable than bulbs for producing
plants by micro-propagation, because it is not necessary to destroy
the plants and because leaves are less contaminated by pathogens
than bulbs.
The cultivation experiments of Ayan et al. (2004) highlighted
the potential of some plant growth regulators (PGRs) like GA3 and
NAA, for obtaining larger plants. Plants grown under shaded conditions produce more alkaloids than those grown in full light (Kutbay
and Kilinç, 1993; Ayan et al., 2004). Combining shading and PGR
application could increase the production of galanthamines in in
vitro cultures (Ayan et al., 2004). Galanthamine biosynthesis is
also influenced by the concentration of nutrients in the medium.
Georgiev et al. (2009) proposed as an optimal medium for the
galanthamine production by a L. aestivum shoot culture the following concentration of nutrients: 4.50 g/L KNO3 , 0.89 g/L NH4 NO3 ,
1.25 g/L (NH4 )(2) SO4 , 0.10 g/L KH2 PO4 and 60 g/L sucrose. Addition of the precursors tyrosine and phenylalanine in the medium
enhanced the biosynthetic activity (Stanilova et al., 2009). Increasing N in the substrate resulted in higher bulb yield (Çirak et al.,
2004).
Human impact and use
The main threat to L. aestivum is the collection of plants to
extract galanthamines and other alkaloids used in the pharmaceu-
327
tical industry (Berkov et al., 2008). To extract 1 kg of galanthamine
c. 1 tonne of bulbs are needed, as galanthamine concentrations are
0.1–0.2%. Large-scale collection has resulted in the decline of L. aestivum and further collection could lead to the disappearance of the
plant from its natural habitats (Uherčíková, 1998; Ayan et al., 2004;
Çiçek et al., 2007; Berkov et al., 2008). Turkey exports up to 6 million
bulbs every year collected from natural populations for the production of galanthamines (Ayan et al., 2004). However, methods for the
in vitro cultivation of the plant have recently been developed and
may reduce the pressure on natural populations. Another threat
to L. aestivum is the destruction of habitats. Due to the intensification of agriculture, many wetlands have been drained in the last
decades and the habitats of L. aestivum have been destroyed.
L. aestivum is widely cultivated as an ornamental plant in gardens and flowerbeds of temperate regions of the world, also outside
of its natural range (e.g. in the USA), since L. aestivum is an attractive plant that can be easily transplanted and cultivated. A widely
cultivated horticultural variety is “Gravetye Giant”, which grows
more vigorously and has larger flowers than the wild type.
Conservation status
L. aestivum is not a very rare plant, but in recent decades it has
declined due to the destruction of wetlands and harvesting for alkaloid production (Geneletti, 2007; Berkov et al., 2008). L. aestivum
is included in several national red data lists. According to the IUCN
Categories and Criteria (IUCN, 2001) it is listed as “Vulnerable” in
the Carpathian area (Witkowski et al., 2003), Romania (Mardari
et al., 2009) and Switzerland (Moser et al., 2002), and as “Least Concern” in Italy and Britain (Conti et al., 1997; Cheffings and Farrell,
2005). It is also included in the Russian Red Data Book (Iliashenko
and Iliashenko, 2000), in the Red Data Book of Ukraine (ShelyagSosonko et al., 1996) and in the list of threatened species of the
Pyrenees (Largier, 2003) that, however, do not use the IUCN criteria.
Globally, it is probably not threatened yet.
L. aestivum is legally protected in several countries and regions,
such as Italy (Lombardy and Emilia-Romagna), Slovakia (Slovak
Commission for Education and Culture, 1958) and France (Crellin,
2005), in Ramsar sites of Hungary (Central Agricultural Office,
2008), in Switzerland, Germany and Bulgaria. Here, since 1998 the
harvesting of the plant is allowed only to obtain genetic material
(Gussev et al., 2003). L. aestivum is not specifically mentioned in
the most important international conventions (i.e. Berne, CITES,
“Habitats” Directive), but some habitats where the species occurs
are listed in the Ramsar Convention and in the “Habitats” Directive
(see plant communities).
Recently, as part of practical conservation efforts, L. aestivum has
been used to restore wetland habitats (Rossi and Dominione, 2005).
Plants propagated ex situ in the botanical garden of the University
of Pavia have been used successfully to create new populations
and reinforce existing ones in N-Italy (Leonardi and Rossi, 2001;
Rossi and Dominione, 2005). Since native plants are not commonly
marketed, in 2010 the Lombardy Region has funded the project
“POT PLANT”, with the aim of creating a production chain of wild
plants (including L. aestivum) to be used for gardening or translocation activities. In Bulgaria, to ensure a sustainable use of natural
populations, ex situ conservation efforts were developed to assess
the possibility of using seventeen natural populations as donors of
germplasm, and to improve in vitro techniques and field cultivation practices like rapid bulb multiplication, and breeding of high
reproductive clones (Gussev et al., 2003). For some pilot areas of
southeastern France like the Port-Cros National Park, a dynamic
management has been proposed to conserve L. aestivum subsp.
pulchellum (Médail et al., 1995).
328
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
Acknowledgements
The authors are grateful to Dr. A. Mondoni (LSB – University
of Pavia) for useful suggestions regarding the seed germination
tests and for critical comments on the manuscript, to Dr. Erik
Welk who kindly provided the distribution map of Fig. 2 (AG
Chorology, Institute for Biology/Geobotany Halle, Germany), and
to two anonymous reviewers for their valuable comments to the
manuscript and their constructive suggestions. We also thank C.
Amosso (Biella), J. Belotti (University of Pavia), P. Cauzzi (University of Pavia), S. Ciappetta (Domodossola), G. Decanis (Imperia),
V. Dominione (Pavia), Dr. R. Gentili (University of Milan-Bicocca),
A. Morini (Pavia), A. Podrini (University of Rome, La Sapienza), E.
Vegini (University of Pavia) for their aid during field and laboratory
work. We thank also Pepi Bareka (University of Patras), Patrick Grillas (Tour du Valait), Frédéric Médail (University of Marseille), Fred
Rumsey (Natural History Museum, London), Arne Strid (University
of Copenhagen), Gianluigi Bacchetta (University of Cagliari), Riccardo Guarino (University of Palermo), Harald Pauli and Michael
Gottfried (University of Vienna) for information on the distribution
of L. aestivum. The authors are grateful to Odile Weber and Paul
Wilkin (R.B.G. Kew) and Fred Rumsey (Natural History Museum,
London) for information about the type species. We thank Dr.
Bruno Foggi (University of Firenze) for his help in the taxonomical interpretation of the subsp. pulchellum. We thank N. Ardenghi
(University of Pavia) for the original drawings on Leucojum, and A.
Picco and M. Rodolfi (University of Pavia) for the determination of
pathogenic fungi.
Last but not least, we thank F. Bonali (Cremona), G. Brusa
(Varese), F. Giordana (Cremona), A. Petraglia (University of Parma),
F. Pistoja (Pavia), P. Rovelli (Milano) and A. Truzzi (Mantova) for
reporting locations of Leucojum populations in N-Italy.
References
Aizpuru, I., Aperribay, J.A., Garin, F., Oianguren, I., Olariaga, I., Vivant, J., 2001. Contribuciones al conocimiento de la flora del País Vasco. Munibe 51, 41–58.
Athanasiadis, N., Drossos, E., 1992. Leucojo-Fraxinetum parvifoliae Glavac 59 and
Pruno-Fraxinetum Oberdorfer 53 of the Thessalian Pinios Delta (Greece). Bot.
Helv. 102, 159–170.
Ayan, K.A., Sait Kurtal, E., Cüneit, C., Kevseroğlu, K., 2004. Bulb yield and some
plant characters of summer snowflake (Leucojum aestivum L.) under shading
as affected by GA3 and NAA at different concentrations. J. Agron. 3, 296–300.
Baker, J.G., 1888. Handbook of the Amaryllidaceae. London.
Bareka, P., Kamari, G., Phitos, D., 2003. Cytogeographic study of the genus Leucojum
(Amaryllidaceae) in Greece. Bocconea 16, 529–536.
Bareka, P., Kamari, G., Phitos, D., 2006. Acis ionica (Amaryllidaceae), a new species
from the Ionian area (W Greece, S Albania). Willdenowia 36, 357–366.
Baričevič, D., Bernáth, J., Maggioni, L., Lipman, E., compilers, 2004. Report of a working group of medicinal and aromatic plants. First Meeting, 12–14 September
2002, Gozd Martuljek, Slovenia. International Plant Genetic Resource Institute,
Rome, Italy.
Barros-Neves, J., 1939. Contribution à l’étude caryologique du genre Leucojum. Bol.
Soc. Broteriana 13, 545–572.
Bergmeier, E., 1988. Floristic notes on the Kato Olimbos area (NE Thessaly, Greece).
Willdenowia 17, 37–58.
Berkov, S., Codina, C., Viladomat, F., Bastida, J., 2008. N-alkylated galanthamine
derivatives: potent acetylcholinesterase inhibitors from Leucojum aestivum.
Bioorg. Med. Chem. Lett. 18, 2263–2266.
Bogdanova, Y., Stoeva, T., Yanev, S., Pandova, B., Molle, E., Burrus, M., Stanilova, M.,
2009. Influence of plant origin on propagation capacity and alkaloid biosynthesis
during long-term in vitro cultivation of Leucojum aestivum L. In Vitro Cell. Dev.
Plant. 45, 458–465.
Bolòs, O., Vigo, J., 2001. Flora dels Països Catalans 4. Fund. Jaume I and Barcino,
Barcelona.
Bondev, I. (Ed.), 1995. Chorological Atlas of Bulgarian Medicinal Plants. Pensoft, Sofia,
272pp.
Buxbaum, F., 1934. Leucojum. In: Wangerin, W., Schröter, C. (Eds.), Lebensgeschichte
der Blütenpflanzen Mitteleuropas, Bd. 1, Abt. 3. Ulmer, Stuttgart, pp. 745–765.
Čarni, A., Franjiċ, J., Škvorc, Ž., 2004. Crataegus nigra Waldst. et Kit. dominated community in the flooded Danube River Area in Croatia. Hacquetia 3/2, 81–90.
Cater, M., Kutnar, L., Accetto, M., 2001. Slovenian lowland and floodplain forests. In:
Klimo, E., Hager, H. (Eds.), The Floodplain Forests in Europe: Current Situation
and Perspectives. Brill, Leiden, pp. 233–248.
Čejka, T., Horsák, M., Némethová, D., 2008. The composition and richness of Danubian floodplain forest land snail faunas in relation to forest type and flood
frequency. J. Mollus. Stud. 74, 37–45.
Central Agricultural Office, 2008. Second Country Report Concerning the State of
Plant Genetic Resources for Food and Agriculture. Ministry of Agriculture and
Rural Development, Hungary.
Cheffings, C.M., Farrell, L. (Eds.), 2005. The Vascular Plant Red Data List for Great
Britain. Joint Nature Conservation Committee, Peterborough.
Chiappini, M., 1964. Il Leucojum aestivum L. v. pulchellum (Salisb.) in Sardegna. Note
critiche ed areale sardo. Archiv. Geobot. Biogeograf. Ital. 40, 298–307.
Chiappini, M., Scrugli, A., 1970. Ricerche citotassonomiche in Leucojum aestivum L.
Morisia 2, 17–28.
Çiçek, E., Aslan, M., Tilki, F., 2007. Effect of stratification on germination of Leucojum
aestivum L. seeds, a valuable ornamental and medicinal plant. Res. J. Agric. Biol.
Sci. 3, 242–244.
Çirak, C., Ayan, A.K., Kurtar, E.S., Kevs Eroglu, K., Çamas, N., 2004. The effects of
different N doses and harvesting times on bulb yield and some plant characters
of summer snowflake (Leucojum aestivum L.). Asian J. Plant Sci. 3, 193–195.
Contandriopoulos, J., 1962. Recherches sur la flore endémique de la Corse et sur ses
origines. Ann. Fac. Sci. Marseille 32, 1–354.
Conti, F., Abbate, G., Alessandrini, A., Blasi, C., 2005. An Annotated Check-list of the
Italian Vascular Flora. Palombi editore, Roma.
Conti, F., Manzi, A., Pedrotti, F., 1997. Liste Rosse Regionali delle Piante d’Italia. WWF
Italia, Società Botanica Italiana, CIAS, Università di Camerino, Camerino.
Cowling, R.M., Rundel, P.W., Lamont, B.B., Kalin Arroyo, M., Arianoutsou, M.,
1996. Plant diversity in mediterranean-climate regions. Trends Ecol. Evol. 11,
362–366.
Crellin, J., 2005. www.amaryllidaceae.org/Leucojum (accessed September 2010).
Cummins, G.B., 1971. The Rust Fungi of Cereals, Grasses and Bamboos. SpringerVerlag, New York.
D’Amato, G.F., Bianchi, G., 1999. The chromosome banding of some Italian Amaryllidaceae. Caryologia 52, 87–92.
Davis, L.G., 1966. Systematic Embryology of the Angiosperms. Wiley, New York.
Denk, T., Frotzler, N., Davitashvil, N., 2001. Vegetational patterns and distribution of
relict taxa in humid temperate forests and wetlands of Georgia (Transcaucasia).
Biol. J. Linn. Soc. 72, 287–332.
Diadema, K., Médail, F., Affre, L., Castagné, H., Torre, F., 2004. Ecology and demography of two endangered narrow endemic plants (Leucojum, Amaryllidaceae) in
southern France. In: Arianoutsou, M., Papanastasis, V.P. (Eds.), Ecology, Conservation and Management of Mediterranean Climate Ecosystems. Milpress,
Rotterdam, pp. 1–9.
Diop, M.F., Hehn, A., Ptak, A., Chrétien, F., Doerper, S., Gontier, E., Bourgaud, F., Henry,
M., Chapleur, Y., Laurain-Mattar, D., 2007. Hairy root and tissue cultures of Leucojum aestivum L. – relationships to galanthamine content. Phytochem. Rev. 6,
137–141.
Dobeš, C., Hahn, B., Morawetz, W., 1997. Chromosomenzahlen zur GefäßpflanzenFlora Österreichs. Linzer Biol. Beitr. 29, 5–43.
Duchaufour, P., 1995. Pédologie. Sol, Vegetation, Environnement. Masson, Paris.
Eichhorn, J., Takada, T., Kita, Y., Zenk, M.H., 1998. Biosynthesis of the Amaryllidaceae
alkaloid galanthamine. Phytochemistry 49, 1037–1047.
Ekici, N., Dane, F., 2008. Cytological and histological studies on female gametophyte
of Leucojum aestivum (Amaryllidaceae). Biologia 63, 67–72.
Ellenberg, H., 1988. Vegetation Ecology of Central Europe, 4th ed. Cambridge University Press, Cambridge.
Ellenberg, H., Weber, H.E., Düll, R., Wirth, V., Werner, W., Paulißen, D., 2001. Zeigerwerte von Pflanzen in Mitteleuropa, Scripta Geobotanica Band 18, Göttingen.
Ellenberg, H., Klötzli, F., 1972. Waldgesellschaften und Waldstandorte in Schweiz.
Mitt. Anst. Forstl. Vers., 930.
European Commision, 2007. Interpretation Manual of European Union Habitats.
Bruxelles.
FAO, 1998. World Reference Base for Soil Resources by ISSS-ISRIC-FAO. World Soil
Resources Report 84, Rome.
Farrell, L., 1979. The distribution of Leucojum aestivum L. in the British Isles. Watsonia
12, 325–332.
Farrell, L., 1982. The distribution of Leucojum aestivum L. in Ireland. Ir. Nat. J. 20, 483.
Fischer, M., Oswald, K., Adler, W., 2008. Exkusionsflora für Österreich, Liechtenstein,
Südtirol. 3. Auflage. Biologiezentrum der Oberösterreichischen Landesmuseen,
Linz. pp. 427–429.
Fitter, A.H., 1978. An Atlas of the Wild Flowers of Britain and Northern Europe.
Collins, London.
Gay, M.J., 1859. Note sur une anomalie bulbaire du Leucojum aestivum. Bull. Soc. Bot.
Fr. 6, 266–267.
Geneletti, D., 2007. An approach based on spatial multicriteria analysis to map the
mature conservation value of agricultural land. J. Environ. Manage. 83, 228–235.
George, A.S., 1987. Leucojum. In: George, A.S. (Ed.), Flora of Australia 45. Australian
Government Publishing Service, Canberra, pp. 380–382.
Georgiev, V., Berkov, S., Georgiev, M., Burrus, M., Codina, C., Bastida, J., Ilieva,
M., Pavlov, A., 2009. Optimized nutrient medium for galanthamine production in Leucojum aestivum L. in vitro shoot system. Z. Naturforsch. 64,
219–224.
Georgieva, L., Berkov, S., Kondakova, V., Bastida, J., Viladoma, F., Atanassov, A., Codina, C., 2007. Alkaloid variability in Leucojum aestivum from wild populations. Z.
Naturforsch. 62, 627–635.
Girmen, M., Zimmer, K., 1987. In-vitro-Kultur von Leucojum aestivum L. Gartenbauwissenschaft 52, 149–151.
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
Grabherr, G., Mucina, L., 1993. Die Pflanzengesellschaften Österreichs, Teil II. Natürliche waldfreie Vegetation. Gustav Fischer Verlag, Jena, Stuttgart, New York.
Guinea Lopez, E., Ceballos Jimenez, A., 1974. Elenco de la flora vascular Española.
Icona, Madrid.
Guinochet, M., de Vilmorin, R., 1978. Flore de France. Centre National de la Recherche
Scientifique, Paris.
Gussev, C., Uzunov, D., Bosseva, Y., Stoeva, T., Stanilova, M., Burrus, M., 2003. Conservation of Leucojum aestivum (Amaryllidaceae) in Bulgaria. Bocconea 16 (2),
815–821.
Harley, J.L., Harley, E.L., 1987. A check-list of mycorrhiza in the British flora –
addenda, errata and index. New Phytol. 107, 741–749.
Healy, A.J, Edgar, E., 1980. Amaryllidaceae. Flora of New Zealand, 3. P. D. Hasselberg.
Government Printer, Wellington.
Heinrich, M., Lee Teoh, H., 2004. Galanthamines from snowdrop – the development
of a modern drug against Alzheimer’s disease from local Caucasian knowledge.
J. Ethnopharmacol. 92, 147–162.
Hess, H.E., Landolt, E., Hirzel, R., 1967. Flora der Schweiz. Birkhäuser Verlag, Basel
und Stuttgart.
Hill, M.O., Preston, C.D., Roy, D.B., 2004. PLANTATT – Attributes of British and Irish
Plants: Status, Size, Life History, Geography and Habitats. CEH Publication Sales,
Wallingford.
Horvat, I., Glavač, V., Ellenberg, H., 1974. Vegetation Südosteuropas. Gustav Fischer
Verlag, Stuttgart.
Hurrel, J.A., Delucchi, G., 2007. Amaryllidaceae adventicias en la Argentina. Bol. Soc.
Argent. Bot. 42, 313–319.
Iliashenko, V.Y., Iliashenko, E.I., 2000. Krasnaya kniga Rossii: pravovye akty (Red
Data Book of Russia: Legislative Acts). State Committee of the Russian Federation
for Environmental Protection, Moscow.
Irmisch, T., 1860. Beiträge zur Morphologie der Amaryllideen. H.W. Schmidt, Halle.
Ito, M., Kawamoto, A., Kita, Y., Kurita, S., 1999. Phylogeny of Amaryllidaceae based
on matK sequence data. Jpn. J. Res. 112, 207–216.
IUCN, 2001. IUCN Red List Categories. Version 3.1. IUCN Species Survival Commission Re-introduction Specialist Group, World Conservation Union, Gland,
Switzerland, Cambridge, UK.
Jarvis, C.E., 2010. The Linnaean plant name typification project and cultivated
plants. http://www.nhm.ac.uk/research-curation/research/projects/linnaeantypification/ (accessed September 2010).
Jordan-Pla, A., Estrelles, E., Boscaiu, M., Soriano, P., Vincente, O., Mateu-Andrés, I.,
2009. Genetic variability in the endemic Leucojum valentinum. Biol. Plantarum
53, 317–320.
Jovanović, S., Tomović, G., Lakušić, D., Niketić, M., Pavlović, M., Boža, P., 2009. Genus
Leucojum L. (Amaryllidaceae) – distribution and threatened status in Serbia. Bot.
Serb. 33, 45–50.
Knuth, P., 1898–1904. Handbuch der Blütenbiologie, vols. 1, 2.1 and 2.2. Wilhelm
Engelmann, Leipzig.
Knuth, P., 1909. Handbook of Flower Pollination (J.R. Ainsworth Davis, Trans.), vol.
3. Clarendon Press, Oxford.
Kohut, E., Ördögh, M., Jámbor-Benczúr, E., Máthé, Á., 2007. Results with the
establishment of in vitro culture of Leucojum aestivum. J. Hortic. Sci. 13,
67–71.
Küenburg, B., Czollner, L., Fröhlich, J., Jordis, U., 1999. Development of a pilot scale
process for the anti-Alzheimer drug (−)-galanthamine using large scale phenolic
oxidative coupling and crystallisation-induced chiral conversion. Org. Process
Res. Dev. 3, 425–431.
Kutbay, H.G., Kilinç, M., 1993. An autoecological study on Leucojum aestivum L. Turk.
J. Bot. 17, 1–4.
Kutbay, H.G., Kilinç, M., Kandemir, A., 1998. Phytosociological and ecological structure of Fraxinus angustifolia subsp. oxycarpa forests in the central Black Sea
Region. Turk. J. Bot. 22, 157–162.
Lambinon, J., Delvosalle, L., Duvigneaud, J., 2004. Nouvelle Flore de la Belgique, du
G.-D. de Luxembourg, du Nord de la France et des régions voisines. 5e ed., Jardin
Botanique National de Belgique.
Largier, G., 2003. Liste rouge provisoire des espèces rares ou menacées de la flore
vasculaire de Midi-Pyrénées. Conservatoire botanique pyrénéen/CBN de MidiPyrénées, Tarbes.
Landolt, E., 1977. Ökologische Zeigerwerte zur Schweizer Flora. Geobotanisches
Institut der ETH, Stiftung Rübel, Heft 64. Zürich.
Lauber, K., Wagner, G., 2000. Flora Helvetica. Haupt, Berne.
Lazowski, W., 2001. Waldgesellschaften der burgenländischen Leithaniederung.
Linzer Biol. Beitr. 33, 827–875.
Leonardi, A., Rossi, G., 2001. La gestione delle piante rare in Pianura Padana: Leucojum aestivum L. in prati e boschi umidi. Inform. Bot. Ital. 33, 244–247.
Linhart, G., 1882. Fungi hungarici exsiccati. Cent. I. mit 19 Tafeln. UngarischAltenburg.
Linnaeus, C., 1753. Species Plant. 1, 289.
Lledó, M.D., Davis, A.P., Crespo, M.B., Chase, M.W., Fay, M.F., 2004. Phylogenetic
analysis of Leucojum and Galanthus (Amaryllidaceae) based on plastid matK and
nuclear ribosomal spacer (ITS) DNA sequences and morphology. Plant Syst. Evol.
246, 223–243.
Maelicke, A., Samochocki, M., Jostok, R., Feherbacher, A., Ludwig, J., Albuquerque,
E.X., Zerlin, M., 2001. Allosteric sensitization of nicotinic receptors by galantamine, a new treatment strategy for Alzheimer’s disease. Biol. Psychiat. 49,
279–288.
Magulaev, A.J., 1986. Chromosome numbers in some species of flowering plants of
the Crimea and Caucasus floras. Bot. Zurn. 71, 1575–1578.
329
Makra, O., Zalatnai, M., 2006. Vegetation types of mosaic-complexes in the MiddleTisza region. Tiscia 35, 73–84.
Marco, L., do Carmo Carreiras, M., 2006. Galanthamine, a natural product for the
treatment of Alzheimer’s disease. Recent Pat. CNS Drug. Discov. 1, 105–111.
Mardari, C., Tănase, C., Oprea, A., Stănescu, I., 2009. Plant species with decorative
value from Romanian Red Lists cultivated in “Anastasie Fătu” Botanic Garden of
Iaşi. J. Plant Develop. 16, 49–54.
Marushevsky, D., 2003. Directory of Azov-Black Sea Coastal Wetlands: Revised and
Updated. Wetlands International, Kiev.
Matthews, V., 1994. The New Plantsman, vol. 1. Royal Horticultural Society, London.
Mazhari, N., 2004. Flora of Iran. Nos. 46,47: Ixioliriaceae, Amaryllidaceae. RIFR, Isfahan.
Médail, F., Ponel, P., Barbero, M., 1994. Les prairies humides de la Garde et du Pradet:
leur rôle dans le maintien de la biodiversité botanique et entomologique du
département du Var (France). Bull. Soc. Linn. Prov. 45, 49–68.
Médail, F., Loisel, R., Rolando, C., 1995. Eléments pour une gestion dynamique des
populations de quatre végétaux protégés des Îles d’Hyères (Var, France). Sci.
Rep. Port-Cros Nation. Park. 16, 19–24.
Médail, F., Verlaque, R., 1997. Ecological characteristic and rarity of endemic plants
from southeast France and Corsica: implication for biodiversity conservation.
Biol. Conserv. 80, 269–281.
Meerow, A.W., Fay, M.F., Guy, C.L., Li, Q.-B., Zaman, F.Q., Chase, M.W., 1999. Systematics of Amaryllidaceae based on cladistic analysis of plastid rbcL and trnL-F
sequence data. Am. J. Bot. 86, 1345–1352.
Meerow, A.W., Francisco-Ortega, J., Kuhn, D.N., Schnell, R.J., 2006. Phylogenetic relationships and biogeography within the Eurasian clade of Amaryllidaceae based
on plastid ndhF and nrDNA ITS sequences: lineage sorting in a reticulate area?
Syst. Bot. 31, 42–60.
Molinier, R., Tallon, G., 1970. Prodrome des unités phytosociologiques observées en
Camargue. Bull. Mus. Hist. Nat. Marseille 30, 5–110.
Moorman, J., 1999. US Patent 5643905 pharmaceutical composition for treating
nicotine dependence.
Mori, G., Kawabata, H., Imanishi, H., Sakanishi, Y., 1991. Effects of temperature on
flower initiation and development in Leucojum aestivum and L., and L. autumnale
L. J. Jpn. Soc. Hortic. Sci. 59, 833–838.
Mori, G., Kawabata, H., Imanishi, H., Sakanishi Y, 1991a. Growth and flowering of
Leucojum aestivum L. and L. autumnale L. grown outdoors. J. Jpn. Soc. Hortic. Sci.
59, 815–821.
Mori, G., Kawabata, H., Imanishi, H., Sakanishi Y, 1991b. Effects of temperature on
flower initiation and development in Leucojum aestivum L. and L. autumnale L. J.
Jpn. Soc. Hortic. Sci. 59, 833–838.
Moser, D.M., 1999. Leucojum aestivum. In: Käsermann, C., Moser, D.M. (Eds.), Merkblätter Artenschutz. Blütenpflanzen und Farne. BUWAL, Bern, pp. 182–183.
Moser, D., Gygax, A., Baumler, B., Wyler, N., Palese, R., 2002. Lista Rossa delle felci
e piante a fiori minacciate della Svizzera. Ufficio Federale Ambiente, Foreste e
Paesaggio, Berna, Centro Rete Svizzera di Floristica, Chambésy, Conservatoire et
Jardin botaniques de la Ville de Genève, Chambésy.
Mucina, L., Grabherr, G., Ellmauer, T., 1993a. Die Pflanzengesellschaften Österreichs.
Teil I. Anthropogene Vegetation. Gustav Fischer, Jena.
Mucina, L., Grabherr, G., Wallnöfer, S., 1993b. Die Pflanzengesellschaften Österreichs. Teil III. Wälder und Gebüsche. Gustav Fischer, Jena.
Oberdorfer, E., 2001. Pflanzensoziologische Exkursionsflora, 8th ed. Ulmer,
Stuttgart.
Onyshchenko, V.A., 2009. Forests of order Fagetalia sylvaticae in Ukraine. Msyakin,
Kiev.
Ottone, C., Rossetti, R., 1980. Condizioni termopluviometriche della Lombardia. Atti
Ist. Geol. Univ. Pavia 29, 28–48.
Özhatay, N., 2002. Diversity of bulbous monocots in Turkey with special reference.
Chromosome numbers. Pure Appl. Chem. 74, 547–555.
Parolo, G., Rossi, G., 2008. Studio popolazionistico di Leucojum aestivum L., specie
vegetale minacciata in Pianura Padana. Inform. Bot. Ital. 40, 173–174.
Pavlov, A., Berkov, S., Court, E., Gocheva, T., Teneva, D., Pandora, B., Georgiev, M.,
Georgiev, V., Yanev, S., Burnus, M., Ilieva, M., 2007. Galanthamine production by
Leucojum aestivum in vitro systems. Process Biochem. 42, 734–739.
Percival, M.S., 1955. The presentation of pollen in certain angiosperms and its collection by Apis mellifera. New Phytol. 54, 353–368.
Phillips, R., Rix, M., 1991. Perennials. Pan Books Ltd., London.
Pignatti, S., 1982. Flora d’Italia. Edagricole, Bologna.
Pinna, M., Uricchio, V.F., Aresta, M., Basset, A., 2007. Rivers and Citizens. Crossborder Experiences in Environmental Protection and Sustainable Development.
Università del Salento, Lecce.
Poldini, L., 1997. Alcune cenosi rare nel Friuli-Venezia Giulia. Gortiana – Atti Museo
Friul. di Storia Nat. 18, 93–110.
Preston, C.D., 2007. Which vascular plants are found at the northern or southern
edges of their European range in the British Isles? Watsonia 26, 253–269.
Rippey, E., Hislop, M.C., Dodd, J., 2007. Reassessment of the vascular flora of Rottnest
Island. J. Roy. Soc. Western Australia 86, 7–23.
Rivas-Martinez, S., Rivas-Sáenz, S., 2009. Sistema de Clasificación Bioclimática
Mundial, 1996–2009, Centro de Investigaciones Fitosociológicas, España.
http://www.ucm.es/info/cif (accessed September 2010).
Rossi, G., Dominione, V., 2005. Un’esperienza dell’Orto Botanico dell’Università di
Pavia. Reintroduzione di Leucojum aestivum L. in Pianura Padana. In: Rinaldi, G.,
Rossi, G. (Eds.), Orti botanici, conservazione e reintroduzione della flora spontanea in Lombardia. Consorzio Parco del Monte Barro, Galbiate, pp. 41–66.
Saccardo, P.A., 1899. Sylloge fungorum XIV, p. 346.
330
G. Parolo et al. / Perspectives in Plant Ecology, Evolution and Systematics 13 (2011) 319–330
Saccardo, P.A., 1913. Sylloge fungorum XXII.
Salisbury, R.A., 1807–1808. The Paradisus Londinensis. William Hooker, London.
Sârbu, A., 2007. Arii speziale pentru protecţia şi conservarea plantelor în România.
Victor B. Victor, Bucareşti.
Ščepánková, I., Hudák, J., 2004. Leaf and tepal anatomy, plastid ultrastructure and
chlorophyll content in Galanthus nivalis L. and Leucojum aestivum L. Plant Syst.
Evol. 243, 211–219.
Schuler, A., 2007. Contribution to the flora of northern and central Greece. Willdenowia 37, 229–241.
Schwikkard, S., van Heerden, F.R., 2002. Antimalarial activity of plant metabolites.
Natl. Prod. Rep. 19, 675–692.
Senel, G., Ozkan, M., Kandemir, N., 2002. A karyological investigation on some
rare and endangered species of Amaryllidaceae in Turkey. Pakistan J. Bot. 34,
229–235.
Servigne, P., 2008. Etude expérimentale et comparative de la myrmécochorie: le cas
des fourmis dispersatrices Lasius niger et Myrmica rubra. Ph.D. Thesis, Université
libre de Bruxelles.
Shelyag-Sosonko, E., Kyiv, Yu.R., Bazhan, M., 1996. Ukrainian Red Data Book of
Ukraine. Plants. Ukrainian Encycklopedy Press, Kiev.
SILENE,
2006–2010.
Conservatoire
Botanique
National
Méditerranéen de Porquerolles, Conservatoire Botanique National Alpin.
http://flore.silene.eu/index.php?cont=accueil (accessed September 2010).
Slovak Commission for Education and Culture, 1958. Order of Commission
for Education and Culture from 23rd December 1958 by which the
protected plant species and conditions of their protection are determined. http://faolex.fao.org/docs/texts/slo43267.doc (accessed September
2010).
Somsak, L., 1992. Leucojum aestivum L. in the interior part of the Zahorska-Nizina
lowland. Biologia 47, 591–592.
Stace, C., 2010. New Flora of the British Isles, 3rd ed. Cambridge University Press,
Cambridge.
Stancic, Z., 2005. Oenantho silaifoliae Alopecuretum pratensis, a new association of
grassland vegetation in Croatia. Period. Biol. 107, 89–99.
Stanilova, M., Ilcheva, V., Zagorska, N., 1994. Morphogenetic potential and in vitro
micropropagation of endangered plant species Leucojum aestivum L. and Lilium
rhodopaeum. Delip. Plant Cell. Rep. 13, 451–453.
Stanilova, M., Hristova, L., Pandova, B., Molle, E., Burrus, M., Yanev, S., 2009. Stimulation of alkaloid biosynthesis in long-term in vitro cultures of Leucojum aestivum
L. (amaryllidaceae). C. R. Acad. Bulg. Sci. 62, 863–870.
Stefanov, J.D., 1990. Ecobiological and phytochemical investigations of natural populations and introduced origins of summer snowflake (Leucojum aestivum L.) in
Bulgaria. DSc Thesis, NIHFI Sofia.
Stern, F.C., 1956. Snowdrops and snowflakes. A study of the genera Galanthus and
Leucojum. Roy. Horticult. Soci. 16, 113–139.
Straley, G.B., Utech, F.H., 2002. Flora of North America. Oxford University Press, New
York.
Tan, K., Mullaj, A., Sfikas, G., Strid, A., 2004. An autumn-flowering Leucojum (Amaryllidaceae) in South Albania and Western Greece. Physe 107, 39–42.
Thomsen, T., Zendeh, H., Fisher, J., Kewitz, H., 1991. In vitro effects of various
cholinesterase inhibitors on acetyl- and butyrylcholinesterase of healthy volunteers Biochem. Pharmacolology 41, 139.
Tutin, T.G., Heywood, V.H., Burges, N.A., Valentine, D.H., 1980. Flora Europaea 5.
Cambridge University Press, Cambridge.
Uherčíková, E., 1998. Structure and dynamics of Leucojum aestivum L. populations in
floodplain forests at Danube river (Slovakia). In: Elias, P. (Ed.), Plant Population
Biology. V Sekos, Bratislava-Nitra. pp. 42–47.
Vladimirov, V., Dane, F., Stevanović, V., Tan, K., 2009. New floristic records in the
Balkans. Phytol. Balcan. 15, 431–452.
Welten, M., Sutter, R., 1982. Verbreitungsatlas der Farn-und Blütenpflanzen der
Schweiz. Birkhäuser Verlag, Basel.
Wendelbo, P., 1970. Flora Iranica (Amaryllidaceae) Akademische Druck-u. Verlagsanstalt Graz, Austria.
Wigginton, M.J., 1999. British Red Data Books 1: Vascular Plants, 3rd ed. JNCC, Peterborough.
Wink, M., 2009. Mode of action and toxicology of plant toxins and poisonous plants.
Mitt. Julius Kühn-Inst. 421, 93–112.
Witkowski, Z.J., Król, W., Solarz, W. (Eds.), 2003. Carpathian list of endangered
species. WWF and Institute of Nature Conservation. Polish Academy of Sciences,
Vienna, Krakow.
Zagorska, N., Stalinova, M., Ilcheva, V., Gadeva, P., 1997. Micropropagation of Leucojum aestivum (Summer Snowflake). In: Bajaj, Y.P.S. (Ed.), Biotechnology in
Agriculture and Forestry. Springer, New York, pp. 178–190.