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Plant Ecology and Evolution 147 (2): 237–255, 2014
http://dx.doi.org/10.5091/plecevo.2014.927
Eight new species of Ixora (Ixoreae - Rubiaceae) from Madagascar
Petra De Block
Botanic Garden Meise, Nieuwelaan 38, BE-1860 Meise, Belgium
E-mail: petra.deblock@br.fgov.be
INTRODUCTION
With an estimated 530 species (Davis et al. 2009), Ixora L.
is one of the largest genera of the Rubiaceae. The genus is
badly known taxonomically. No worldwide monograph ex-
ists, but some recent ora treatments or regional revisions
(e.g., Bridson 1988, 2003, De Block 1998) were published.
Ixora has a pantropical distribution with c. eighty species in
Africa (continental Africa and Madagascar) and c. fty spe-
cies in the Neotropics (Govaerts et al. 2011), but the centre
of diversity is Asia and the Pacic.
Recently, Ixora was the focus of detailed molecular
studies. Mouly et al. (2009) placed Captaincookia N.Hallé,
Doricera Verdc., Myonima Comm. ex A.Juss. and Versteegia
Valeton into synonymy with Ixora and continued the broad-
ening of the genus concept already started by Guédès (1986)
so that Ixora now also includes species with multilocular
ovaries. A detailed study of the phylogeny and biogeography
of the Madagascan Ixora species was also recently published
(Tosh et al. 2013).
Ixora is a genus of shrubs and trees widely distributed
in Madagascar, growing in humid or, more rarely, in (semi-)
deciduous dry forest. The genus is easily recognized by the
following characters: petioles articulate; inorescences ter-
minal; inorescence branching trichotomous, articulate;
owers narrowly tubular, 4-merous; aestivation contorted;
stigma with 2, 3 or 4 lobes; ovary bi-, tri- or tetralocular with
a single ovule per locule; fruits drupaceous; seeds with a
large adaxial excavation (De Block 1998).
In Madagascar, Ixora is represented by c. forty species,
a number that is slightly higher than for continental Africa
(De Block 1998). All but two species, I. platythyrsa Baker
and I. cremixora Drake, are endemic to the great island and
no species are in common with Continental Africa. In the
past, fourteen Madagascan Ixora species were recognized
by Arènes (1960), Baker (1885, 1890), de Candolle (1901),
Drake del Castillo (1897a, 1897b), Hochreutiner (1908), Oli-
ver (1892) and Guédès (1986). More recently, seven species
were newly described (De Block 2007, 2008, 2014). As is
the case with many Madagascan plant groups, a high number
of species remain unnamed, but the author’s revision of the
Madagascan species is underway.
In comparison to continental Africa, Ixora has under-
gone a rare differentiation in Madagascar. Flower size varies
greatly with corolla tubes between 0.4 and 23 cm long (De
Block 2007). The number of owers per inorescence is also
variable: six species have solitary owers and several others
are pauciorous (De Block 2008), whereas in other parts of
the distribution area most Ixora species have inorescences
with numerous owers. Multilocular ovaries, a rare charac-
ter within the genus, occur in four Madagascan species (De
Block 2014). This character is correlated with the presence
of large, thick-walled fruits and small seeds. However, large
fruits also occur in other Madagascan Ixora species, such as
I. siphonantha Oliv. (De Block 1998) or I. foliicalyx Guédès
(De Block & Van De Kerckhove 2009). Despite this differ-
entiation, several Ixora species in Madagascar are difcult to
distinguish. Capuron (1973) wrote: “Le genre Ixora consti-
tue, à Madagascar, un groupe très homogène, où la distinc-
tion des espèces devra se baser sur des caractères de faible
importance tels que la taille des eurs, forme et taille des
lobes calicinaux, stipules etc. ...”.
In this paper, eight new species of Ixora are described,
bringing the number of named species up to 29. Most of the
new species are known from relatively few herbarium speci-
mens. Recent collecting programmes from institutes such as
Missouri Botanical Garden or Conservatoire et Jardin bota-
niques de Genève targeted undercollected regions, such as
All rights reserved. © 2014 Botanic Garden Meise and Royal Botanical Society of Belgium – ISSN 2032-3921
REGULAR PAPER
Background and aims – Ixora L. is one of the largest genera of the Rubiaceae, and badly known
taxonomically. New species are described as a precursor to the author’s revision of Ixora in Madagascar.
Methods – Methods follow normal practice of herbarium taxonomy.
Key results – Eight new Ixora species from Madagascar are recognized. Detailed descriptions, illustrations
and distribution maps are provided for each species.
Key words – Ixora decaryi, Ixora fuscovenosa, Ixora gautieri, Ixora longipedicellata, Ixora masoalensis,
Ixora pallens, Ixora pedalis, Ixora ripicola, Madagascar, Rubiaceae.
238
Pl. Ecol. Evol. 147 (2), 2014
Masoala Peninsula (MBG) or Antsiranana (G). This resulted
in the collection of several new species previously not rep-
resented in herbaria, such as I. fuscovenosa, I. gautieri and
I. pallens. These recent collecting activities also added pre-
cious herbarium material to other undescribed species previ-
ously only known from one or a few specimens, e.g. I. peda-
lis, I. longipedicellata and I. masoalensis, nally allowing
their formal description. Intensive collecting clearly is still
necessary in many regions in Madagascar. This is certainly
the case for the Sambirano Region, two species of which are
described here. Ixora decaryi is unfortunately only known
from historical material, I. longipedicellata from a single
historical and one recent specimen. Difcult access to the lo-
calities where they occur, e.g. Tsaratanana Mountain, is cer-
tainly a reason for the undercollecting.
MATERIAL AND METHODS
Herbarium material of the following institutions was stud-
ied: BR, G, K, MO, P, TAN, TEF, UPS, WAG and Z. Extra
plant material and alcohol preserved samples were collected
during eld work in Madagascar. Terminology follows Rob-
brecht (1988) but leaf shape is described according to the
terminology of simple symmetrical plane shapes (Anony-
mous 1962). Methods follow normal practice of herbarium
taxonomy (de Vogel 1987). In the descriptions, inorescence
size does not include the corollas. Colours and sizes are giv-
en for herbarium specimens (dried plant parts). Colours of
the living plants are given separately. Flowering and fruiting
periods are based on dates given on the labels of herbarium
material.
Specimens are cited per province and alphabetically by
collector. Localities are cited as given by the collectors on
the specimen labels, with region added for information. Co-
ordinates of localities were determined using the online Gaz-
etteer to Malagasy Botanical Collecting Localities (Schatz et
al. 2003). Also, 1:500.000 maps from the Malagasy Institut
National de Géodésie et Cartographie were used. Distribu-
tion maps were drawn using Arcmap 9.2.
Abbreviations used: v., Fivondronana (district); fok.,
Fokotany (canton).
TAXONOMIC TREATMENT
Ixora decaryi De Block, sp. nov.
Foliarum laminis parvis et inorescentias paucioris sessili-
bus Ixora microphylla similis, sed ab ea specie removenda
foliarum laminis apice obtusis vel subacuti (nec acuminatis),
pedicellis brevioribus [0.2–2.5(–3) mm longis versus 2–12
mm], calycibus minoribus (0.8–1.5 mm longis versus 1.5–
3.5 mm), corollae tubis lobisque brevioribus [tubis (0.5–)
0.8–1.1 cm longis versus (2.2–)2.8–4 cm; lobis 3.5–5.5 mm
longis versus 7–12 mm] atque alabastris apice obtusis (vel
rariore ± acutis versus acuminatis in I. microphylla). – Type:
Madagascar, province Antsiranana, Sava, Maromandia, Be-
manevika, 23 Sep. 1922, Decary 1032 (holo-: P).
Small shrub; young internodes brown, smooth; older in-
ternodes grey, corky or aking; all external parts glabrous
or, more rarely, young shoots, midribs below, stipules, in-
orescence axes, pedicels, bracts and bracteoles, ovaries,
calyces and corollas moderately to densely covered with
very short erect hairs (Perrier de la Bâthie 15058). Leaves
mostly grouped terminally on short lateral shoots, petioles
0.2–0.4 cm long; blades elliptic, somewhat obovate or ovate,
1.5–4.2 × 0.6–2 cm, papyraceous, drying brown above,
greyish green to pale brown below; apex obtuse to suba-
cute, base attenuate to cuneate; 7–10 pairs of lateral nerves,
higher order venation coloured darker on lower leaf surface.
Stipules: sheath 1–2 mm long, awn (1–)1.5–3.5 mm long.
Inorescences sessile or more rarely subsessile, lax, with
5–25 owers, articulate throughout, 0.7–2.5 cm wide and
0.7–2.5 cm long; modied inorescence-supporting leaves
absent; central rst order axis 0.2–1 cm long, lateral rst or-
der axes 0.4–1.5 cm long; rst order bracts with stipular parts
fused to an ovate blade with a central awn and foliar parts
forming small leaves; higher order bracts with stipular parts
reduced and foliar parts broadly (basally in inorescence) to
narrowly triangular (higher up in inorescence) and vaulted
or liform (terminally in inorescence), c. 1 mm long. Ul-
timate ower triads: owers subsessile to shortly pedicel-
late; pedicels 0.2–2.5(–3) mm long, pedicels of central and
lateral owers not differing much in length; bracteoles usu-
ally present, opposite at the base of the ovary, narrowly tri-
angular to liform, up to 1(–2) mm long. Flowers: ower
bud with obtuse or acute apex; calyx 0.8–1.5 mm long, tube
up to 0.5 mm long, lobes triangular or narrowly triangular,
0.3–1 mm long, apices acute, smaller interstitial lobes some-
times present; corolla tube (5–)8–11 mm long; corolla lobes
3.5–5.5 mm long, 2–3 mm wide, apices blunt; stamens
spreading at anthesis, laments up to 1 mm long, anthers
3.5–4 mm long; ovary bilocular, c. 1 mm long; style exsert-
ed 3–4 mm, stigmatic lobes 1–2.5 mm long. Fruits slightly
wider than high, bilobed, 0.7–0.8 cm wide, 0.6–0.7 cm long;
fruit wall thin; mature seeds unknown. Fig. 1.
Habitat – Mid-altitude to montane humid forest, altitude:
700–1700 m.
Distribution – Only known from the Soa and Diana Re-
gions in northwestern Madagascar (provinces Antsiranana
and Mahajanga). Fig. 2A.
Phenology – Flowers: September; fruits: February.
Living colours – Corolla white or white tinged pink.
Critical remarks – This species is only known from four
historical specimens. The most recent one was collected in
1951. Collecting efforts in the distribution area of this spe-
cies should be undertaken in order to ascertain its conserva-
tion status. – All material of this species has glabrous veg-
etative and generative parts except for Perrier de la Bâthie
15058. In this specimen the young shoots, stipules, midribs
on the lower leaf surfaces, inorescence axes and pedicels,
ovaries, calyces and corollas are moderately to densely cov-
ered with very short hairs. – The name Ixora decaryi is an
unpublished name taken from herbarium collections at P
(Decary 1057). The author of the name could not be deter-
mined. – Ixora decaryi is most likely to be confused with
one of the other new species, I. longipedicellata, and with I.
microphylla. These three species possess small to relatively
small leaves, and few-owered inorescences. When ower-
ing, the species are easily distinguishable from each other:
239
De Block, Eight new Ixora species from Madagascar
Figure 1 – Ixora decaryi: A, owering branch; B, stipules; C, inorescence (corollas removed); D, bracteole, ovary and calyx; E, corolla,
stamens, style and stigma (A–E, from Perrier de la Bâthie 15058). Drawn by Roger Lala Andriamiarisoa.
240
Pl. Ecol. Evol. 147 (2), 2014
Figure 2 – Distribution maps. A, Ixora decaryi; B, Ixora fuscovenosa; C, Ixora gautieri; D, Ixora longipedicellata.
241
De Block, Eight new Ixora species from Madagascar
I. microphylla, by the long owers with acuminate lobes;
I. longipedicellata, by the small owers (corolla tube 4–5
mm long) with blunt corolla lobes, the oblong to somewhat
foliaceous calyx lobes up to 2.5 mm long and the long pedi-
cels; and, I. decaryi, by the owers of intermediate length
[corolla tubes (5–)8–11 mm long] (table 1). The leaves of I.
microphylla differ from those of both other species by their
somewhat larger size and by the acuminate or apiculate apex.
While the three species occur in the same region, northwest-
ern Madagascar, I. microphylla is a lowland species with a
preference for calcareous soil, whereas the known specimens
of I. decaryi and I. longipedicellata have a submontane to
montane distribution.
Other collections examined – Madagascar: Mahajanga: Soa,
Maromandia, Sandrakota, 23 Sep. 1922, Decary 1057 (P); Soa, de
la Haute Maevarano au Bas Sambirano par Bealanana et la Haute
Sandrakota, 20–25 Feb. 1951, Humbert & Capuron 25432 (K, P);
Soa, environs de Mandritsara, Sep. 1922, Perrier de la Bâthie
15058 (P).
Ixora fuscovenosa De Block, sp. nov.
Ixora emirnensi ob inorescentias pedunculatas corol-
lae tubis potius brevibus similis, sed notabilis calycis
tubis lobisque multo longioribus (1.5–2 mm longis versus
0.3–0.4 mm), corolla tubis alignot longioribus (25–28 mm
longis versus 10–15 mm) et alabastris apice acuminatis. –
Type: Madagascar, Province Antsiranana, Diana, Ambilobe,
commune rurale Beramanja, Chaîne Galoka, mont Galoke,
fok. Anketrabe-Belinta, Galoka relevé 1, 18 Feb. 2005,
Wohlhauser, Tonga, Ravokatra, Lang, Manasse, Claude &
Bocksberger 741 (holo-: G; iso-: BR, K, MO, P, TAN).
Shrub, to 4 m tall; young internodes brown, smooth;
older internodes greyish or greyish brown, corky; all exter-
nal parts glabrous, except for peduncle and inorescence
axes which may be glabrous or sparsely to moderately cov-
ered with very short hairs. Leaves: petioles 0.4–0.8 cm long;
blades elliptic or obovate, 8–12 × 2–4 cm, papyraceous, dry-
ing brown above, somewhat paler below; apex acuminate
with acumen 0.8–2 cm long; base cuneate or acute; 12–18
pairs of lateral nerves, higher order venation coloured darker
and somewhat raised on lower leaf surface. Stipules: sheath
1.5–2.5 mm long, awn 2–5 mm long. Inorescences pedun-
culate, lax, with 5–18 owers, articulate throughout, 4–6 cm
wide and 2–3 cm long; modied inorescence-supporting
leaves present, blades sessile to shortly petiolate (petioles
up to 2 mm long), elliptic to obovate, 2–4 × 1.5–2 cm, base
cordate to rounded; peduncle 2–3 cm long; central rst or-
der axis 1–2 cm long, lateral rst order axes 1.5–3 cm long;
rst order bracts with stipular parts absent and foliar parts
triangular and vaulted; higher order bracts with stipular parts
absent and foliar parts narrowly triangular, up to 2 mm long.
Ultimate ower triads: owers subsessile to shortly pedicel-
late; pedicels 0.5–2 mm long or up to 5 mm long in case of
reduction, pedicels of central and lateral owers not differ-
ing much in length; bracteoles present, opposite at the base
of the ovary or somewhat lower on the pedicel, liform,
0.5–1.25 mm long. Flowers: ower bud with acuminate
apex; calyx 2.5–3.5 mm long, tube c. 1.5 mm long, lobes
oblong or slightly foliaceous, somewhat keeled, 1.5–2 mm
long, apices obtuse to rounded; corolla tube 25–30 mm long;
corolla lobes 8–9 mm long, c. 3 mm wide, apices acuminate;
stamens spreading at anthesis, laments 1–1.5 mm long, an-
thers 2.5–3 mm long; ovary bilocular, c. 1 mm long; style
exserted 2–3 mm, stigmatic lobes 0.75–1 mm long. Fruits:
mature fruits and seeds unknown. Fig. 3.
Habitat – Low-altitude evergreen humid forest, altitude: c.
300 m.
Distribution – Only known from the Chaîne Galoka region
near Ambilobe (province Antsiranana). Fig. 2B.
Phenology – Flowers and young fruits: February.
Living colours – Peduncle, inorescence axes, pedicels,
bracts and bracteoles red; ovary red, calyx whitish; corolla
white; anthers and laments white; style white (based on
photographs by S. Wohlhauser).
Critical remarks – This species is only known from the
type. As a result the description may need to be updated
when more material becomes available. – In dried condition,
the higher order venation is somewhat raised and coloured
darker than the lower leaf surface, hence the species epi-
thet. – Ixora fuscovenosa is characterized by relatively small
leaves, pedunculate inorescences with a moderate number
of owers and relatively short corolla tubes, just as I. gaut-
ieri, I. pallens, I. emirnensis Baker and I. mangabensis Aug.
DC. Amongst these species, I. fuscovenosa is recognized by
the long calyx tube (c. 1.5 mm) and leaf-like, keeled calyx
lobes 1.5–2 mm long, the long stipular awns (2–5 mm long)
and acuminate ower buds and corolla lobes (table 2).
I. decaryi I. longipedicellata I. microphylla
Leaf blade 1.5–4.2 × 0.6–2 cm 1.2–3 × 0.6–1.5 cm 2.5–8.5 × 1.2–3.5 cm
Leaf apex obtuse to subacute obtuse to rounded
acuminate, acumen ≤ 1(–1.5)
cm long or more rarely
apiculate
Pedicel length 0.2–2.5(–3) mm 7–25 mm 2–12 mm
Flower bud apex obtuse or acute obtuse acuminate
Calyx lobes triangular or narrowly
triangular, 0.3–1 mm long
oblong to somewhat foliaceous,
(1–)1.5–2.5 mm long triangular, 0.5–1.5 mm long
Corolla tube length (5–)8–11 mm 4–5 mm (22)–28–35(–40) mm
Corolla lobe length 3.5–5.5 mm 3–4 mm 7–12 mm
Table 1 – Distinguishing characters for Ixora decaryi, I. longipedicellata and I. microphylla.
242
Pl. Ecol. Evol. 147 (2), 2014
Figure 3 – Ixora fuscovenosa: A, vegetative branch; B, owering branch; C, ultimate ower triad (corollas removed); D, bracteole, ovary and
calyx; E, corolla, stamens, style and stigma (A–E, from Wohlhauser et al. 741). Drawn by Antonio Fernandez.
243
De Block, Eight new Ixora species from Madagascar
Ixora gautieri De Block, sp. nov.
Ixora fuscovenosa similis inorescentiis breviter peduncu-
latis, foliarum laminis potius parvis et calycis lobis potius
longis, sed ab illa differt foliarum laminis valde coriaceis et
apice obtusis; praeterea inorescentiis congestioribus et ala-
bastris apice rotundis bene diagnoscenda. – Type: Madagas-
car, province Antsiranana, Sava, sous-préfecture de Vohemar,
commune rurale Daraina, Daraina, forêt d’Antsahabe, 880 m
du point côté 1088, 20 Nov. 2004, Gautier 4705 (holo-: G;
iso-: BR).
Shrub, 2–4 m tall; young internodes brown, smooth;
older internodes greyish or brown, corky; all external parts
glabrous. Leaves: petioles 0.1–0.2(–0.4) cm long; blades el-
liptic or broadly elliptic, more rarely somewhat ovate or obo-
vate, 3–8 × 1.2–3.5 cm, strongly coriaceous, drying brown
and somewhat glossy above, brown below; apex obtuse; base
acute to cuneate; 11–13 pairs of lateral nerves; secondary
and higher order venation somewhat raised on both surfaces.
Stipules: sheath 1–2 mm long, awn 1–2 mm long. Inores-
cences shortly pedunculate or more rarely subsessile, mod-
erately compact, with 15–30 owers, articulate throughout
except sometimes between ovary and pedicel; 1–2.5 cm wide
and 1–2 cm long; modied inorescence supporting leaves
present, blades subsessile, not differing in shape from veg-
etative ones, 0.4–1.5 × 0.15–0.7 cm; peduncle 0.1–1.2 cm
long; central rst order axis 0.1–1 cm long, lateral rst order
axes 0.4–1.8 cm long; rst order bracts with stipular parts
reduced or absent and foliar parts narrowly triangular and
vaulted, up to 2 mm long (in pedunculate inorescences),
or more rarely (in subsessile inorescences) stipular parts
fused to an ovate sheath with a central awn and foliar parts
forming small leaves; higher order bracts with stipular parts
absent, foliar parts narrowly triangular, 1.5–2 mm long. Ulti-
mate ower triads: owers subsessile to shortly pedicellate;
pedicels 0.5–3 mm long, pedicels of central owers often
somewhat shorter than those of lateral owers; bracteoles
present, opposite at the base of the ovary, narrowly trian-
gular, 1–1.5 mm long. Flowers: ower bud with rounded
apex; calyx 1.2–2 mm long, drying paler than the ovary, tube
0.5–0.6 mm long, lobes ovate or broadly ovate, often some-
what unequal within one ower, 0.8–1.2 mm long, apices
rounded; corolla tube 22–26 mm long; corolla lobes 4–7 mm
long, 3–3.5 mm wide, apices blunt; stamens spreading at an-
thesis, laments 1–1.5 mm long, anthers 3–4 mm long; ovary
bilocular, c. 0.8 mm long, drying blackish; style exserted
I. fuscovenosa I. pallens I. gautieri I. emirnensis I. mangabensis
Pubescence of
peduncle and
inorescence axes
present or absent absent absent absent present or absent
Petiole length 0.4–0.8 cm 0.6–1.5 cm 0.1–0.2(–0.4) cm 0.2–1(–1.5) cm 0.1–0.7 cm
Leaf base cuneate or acute cuneate or rarely
acute acute to cuneate
cuneate to acute
or rounded, rarely
attenuate
acute, obtuse,
rounded or cordate
Leaf blade colour brown pale greenish or
pale brownish brown (dark) brown (dark) brown
Leaf blade texture papyraceous papyraceous strongly coriaceous papyraceous or
subcoriaceous
papyraceous, more
rarely coriaceous
Leaf blade apex acuminate, acumen
0.8–2 cm long
acuminate, acumen
0.4–1.6 cm long obtuse acuminate, acumen
up to 1 cm long
acuminate, acumen
0.4–2 cm long
Higher order veins darker on lower
leaf surface not discolourous not discolourous darker on lower
leaf surface
darker on lower
leaf surface
Stipular awn length 2–5 mm 0.5–1(–2) mm 1–2 mm 1–3 mm 1.5–6 mm
Peduncle length 2–3 cm 6–8 cm 0.1–1.2 cm 2–10 cm 1.5–16 cm
Pedicel length 0.5–2(–5) mm 2–8 mm, up to
15 mm in fruit 0.5–3 mm 0–3 mm 1–4(–7) mm
Bracteoles liform,
0.5–1.25 mm long
liform,
0.5–1 mm long
narrowly triangular,
1–1.5 mm long
liform,
0.25–0.8 mm long
liform,
0.5–2.2 mm long
Calyx tube length c. 1.5 mm 0.2–0.4 mm 0.5–0.6 mm 0.2–0.3 mm 0.2–0.5 mm
Calyx lobes
oblong or slightly
foliaceous,
1.5–2 mm long
broadly triangular
or broadly ovate,
0.3–0.5 mm long
ovate or broadly
ovate, 0.8–1.2 mm
long
triangular,
0.3–0.4 mm long
triangular or
narrowly triangular,
0.5–1 mm long
Calyx lobes apices obtuse to rounded rounded rounded obtuse to rounded acute
Corolla tube length 2.5–3 cm 2–2.6 cm 2.2–2.6 cm 1–1.5 cm 2–2.6(–3.2) cm
Corolla lobes length 0.8–0.9 cm 0.6–0.7 cm 0.4–0.7 cm 0.3–0.5 cm 0.5–0.7 cm
Filament length 1–1.5 mm 0.5–1 mm 1–1.5 mm 0.7–1 mm c. 0.5 mm
Flower bud acuminate obtuse rounded acute acuminate
Table 2 – Distinguishing characters for Ixora fuscovenosa, I. pallens, I. gautieri, I. emirnensis and I. mangabensis.
244
Pl. Ecol. Evol. 147 (2), 2014
Figure 4 – Ixora gautieri: A, owering branch; B, node below inorescence, showing stipules and petioles of vegetative leaf pair, stipules
and small leaf blades of inorescence-supporting leaves and base of peduncle; C, ultimate ower triad (corollas removed); D, bracteole,
ovary and calyx; E, fruit (A–D, from Gautier 4705; E, from Ranirison & Nusbaumer 1140). Drawn by Mia Scheerlinck.
245
De Block, Eight new Ixora species from Madagascar
3.5–4 mm, stigmatic lobes 1–1.5 mm long. Fruits bilobed;
mature fruits and seeds unknown. Fig. 4.
Habitat – Mid-altitude forest, often on mountain ridges, alti-
tude: 900–1060 m.
Distribution – Only known from the region of Daraina in
northern Madagascar (province Antsiranana). Fig. 2C.
Phenology – Flowers: November; fruits: immature fruits re-
corded in January.
Living colours – Corolla white, tips of corolla lobes pink in
bud.
Critical remarks – Ixora gautieri ressembles I. fuscovenosa
and other species by the relatively small leaves, the pedun-
culate inorescences with a moderate number of owers and
the relatively short corolla tubes. Amongst these species,
I. gautieri can be differentiated by the strongly coriaceous
leaves with obtuse tips, by the not-discolourous higher or-
der venation, and by the rounded tips of the ower buds (ta-
ble 2).
Other collections examined – Madagascar: Antsiranana: Sava,
sous-préfecture de Vohemar, commune rurale Daraina, fok. Anki-
jabe, forêt de Binara, camp 1, 1.8 km SW du camp, 10 Nov. 2001,
Gautier & Ravelonarivo 4158 (BR, G); Sava, sous-préfecture de
Vohemar, commune rurale Daraina, Daraina, forêt d’Antsahabe,
550 m du point côté 1099, 29 Jan. 2006, Ranirison & Nusbaumer
1140 (BR, G).
Ixora longipedicellata De Block, sp. nov.
Foliis parvis et inorescentiis paucioris laxis Ixora micro-
phylla afnis, sed differt corollae tubis lobisque multo bre-
vioribus (tubis 4–5 mm longis versus 22–40 mm in I. mi-
crophylla; lobis 3–4 mm longis versus 7–12 mm), alabastris
apice obtusis (versus acuminatis) et foliorum laminis obtu-
sis vel rotundis (versus acuminatis). – Type: Madagascar,
Province Mahajanga, Betsiboka, environs de Montagne de
Tsaratanana, Sep. 1912, Perrier de la Bâthie 3745 (holo-: P;
iso-: P).
Shrub; young internodes brown, smooth, sparsely to
moderately covered with short erect hairs; older internodes
greyish, corky; all external parts glabrous except for young
internodes, inorescence axes and pedicels. Leaves grouped
terminally on short lateral shoots; petioles 0.1–0.3 cm long;
blades obovate or broadly obovate, 1.2–3 × 0.6–1.5 cm,
papyraceous, drying brownish above, paler brown or grey-
ish green below; apex obtuse to rounded; base cuneate; 5–8
pairs of lateral nerves. Stipules caducous; sheath c. 1 mm
long, awn 1.5–5 mm long (only visible in youngest stipule
pairs). Inorescences sessile, very lax, with 3–5(–9) ow-
ers, articulate throughout, 2.5–5 cm wide and 1.2–3 cm long;
modied inorescence-supporting leaves absent; inores-
cence axes sparsely to moderately covered with short erect
hairs; central rst order axis 0.2–0.6 cm long, lateral rst or-
der axes 1–2.5 cm long; rst order bracts with stipular parts
fused to an ovate sheath with a central awn and foliar parts
absent or forming small leaves; higher order bracts either as
rst order bracts but somewhat reduced or with stipular parts
absent and foliar parts triangular and vaulted, somewhat m-
briate or liform, up to 2 mm long. Ultimate ower triads:
owers long pedicellate; pedicels 7–25 mm long; pedicels
of central and lateral owers not differing much in length;
bracteoles present, opposite on the pedicel below the ovary,
more rarely at the base of the ovary, liform, 1–2 mm long.
Flowers: ower bud with obtuse apex; calyx 1.5–2.75 mm
long, tube c. 0.3 mm long, lobes oblong to somewhat folia-
ceous, (1–)1.5–2.5 mm long, apices obtuse to rounded; co-
rolla tube 4–5 mm long; corolla lobes 3–4 mm long, c. 2 mm
wide, apices obtuse; stamens spreading at anthesis, laments
1–1.5 mm long, anthers c. 2.5 mm long; ovary bilocular, c.
1 mm long, drying dark brown or blackish; style exserted
3–4.5 mm, stigmatic lobes 1.25–2 mm long. Fruits subglo-
bose, 0.4–0.5 cm in diameter; fruit wall thin; seeds unknown.
Fig. 5.
Habitat – Forest, altitude: 1100–1350 m.
Distribution – Only known from the Soa and Betsiboka
Regions (province Mahajanga). Fig. 2D.
Phenology – Flowers: September – November; fruits: Sep-
tember.
Living colours – Corolla white; fruits red.
Critical remarks – The specimen collected by Perrier de la
Bâthie was annotated as I. longipedicellata in P, but no au-
thor is indicated and the name was never published. – The
fruit dimensions given here are provisional. Although Perrier
de la Bâthie indicated the fruits as red, i.e. mature, they seem
very small for Ixora. Since there is only one fruit available,
the maturity could not be checked. – For almost one hun-
dred years the type specimen was the only material known
for I. longipedicellata. Only recently a second specimen
was collected, indicating that this species is not extinct. – I.
longipedicellata can be confused with I. decaryi and I mi-
crophylla, both species with small leaves and few-owered
inorescences. Table 1 gives the characters to distinguish
them.
Other collections examined – Madagascar: Mahajanga: Soa,
Bealanana, forêt de moyenne altitude située à 7 km NE de la com-
mune rurale de Mangindrano, Nov. 2005, Rakotovao 2606 (BR,
MO, P, TAN).
Ixora masoalensis De Block, sp. nov.
Foliarum laminis magnis crassisque in sicco stramineis Ixora
crassipedi afnis, a qua differt corollarum tubis breviori-
bus (10–12 cm longis versus 17–22.5 cm) et inorescentiis
paucioris solummodo 8–25 (versus 15–50) oribus muni-
tis. – Type: Madagascar, Province Toamasina, Analanjirofo,
Masoala Peninsula, north trail, N of Androka River, climb-
ing hills E of Ambanizana, 17 Dec. 1990, Schatz & Modeste
3068 (holo-: MO; iso-: K, P, TAN).
Shrub or tree, 0.5–7 m tall; young internodes orange or
reddish brown, smooth, older internodes dark brown, some-
what corky; all external parts glabrous. Leaves: petioles
1–2.5 cm long; blades ovate or elliptic to narrowly elliptic,
15–30 × 4.5–11.5 cm, coriaceous or subcoriaceous, drying
yellowish or pale greenish above, somewhat paler below;
apex obtuse to acute; base attenuate; 14–25 pairs of lateral
nerves. Stipules: sheath 3–4 mm long, awn very short, hard-
ly exceeding sheath. Inorescences sessile, lax, with 8–25
owers, articulate throughout, 1.5–6 cm wide and 2–4 cm
long; modied inorescence-supporting leaves absent; cen-
tral rst order axis 0.1–1 cm long, lateral rst order axes
246
Pl. Ecol. Evol. 147 (2), 2014
Figure 5 – Ixora longipedicellata: A, owering branch; B, bracteole, ovary and calyx; C, corolla, stamens, style and stigma (A–C, from
Perrier de la Bâthie 3745). Drawn by Antonio Fernandez.
247
De Block, Eight new Ixora species from Madagascar
Figure 6 – Ixora masoalensis: A, owering branch; B, ultimate ower triad (corollas removed); C, fruit (A & B, from Schatz & Modeste
3068; C, from Zjhra & Hutcheon 323). Drawn by Antonio Fernandez.
0.5–2.5 cm long; rst (and sometimes also second) order
bracts with stipular parts fused into a blade with central awn
and foliar parts absent or forming small leaves; higher or-
der bracts with stipular parts absent, foliar parts triangular
and vaulted, or, higher up in the inorescence, mbriate or
linear. Ultimate ower triads: owers sessile to shortly pedi-
cellate; pedicels 0–1(–1.5) mm long, up to 15 mm long in
case of reduction, pedicels of central and lateral owers not
differing much in length; bracteoles usually present, oppo-
site at the base of the ovary, narrowly triangular to liform,
up to 1 mm long. Flowers: ower bud with rounded apex;
calyx c. 1 mm long, tube 0.5–0.8 mm long, lobes triangular,
somewhat unequal, 0.3–0.6 mm long, apices acute, obtuse or
rounded; corolla tube 10–12 cm long; corolla lobes 1.7–3 cm
long, 0.3–0.4 cm wide; apices rounded; stamens sessile,
anthers not spreading at anthesis but remaining erect (their
bases included in the corolla tube over a length of c. 4 mm),
8–11 mm long; ovary bilocular, c. 2 mm long; style exserted
7–10 mm, stigmatic lobes 2.5–5 mm long. Fruits subglobose,
slightly wider than high, bilobed, 1.1–1.3 cm wide, 1–1.2 cm
long; fruit wall thin; seeds c. 0.85 cm long, c.0.6 cm wide.
Fig. 6.
Habitat – Lowland humid eastern forest, altitude: 200–700
m.
Distribution – Northern Madagascar. Known from the Sam-
bava-Marojejy region and from Masoala Peninsula (provinc-
es Antsiranana and Toamasina). Fig. 7A.
Phenology – Flowers: October – February; fruits: May –
June.
Living colours – Ovary and calyx green, sometimes calyx
lobes tinged reddish near margin; corolla greenish near the
base, white higher up; stamens white; style and stigma white.
Flowers fragrant.
Vernacular names – Vongabe; vorigo.
Critical remarks – Ixora masoalensis is similar to I. cras-
sipes Boivin ex De Block by the large, pale-drying, coria-
ceous leaves, the short-awned stipules, the robust inores-
cence axes, the small ovaries and reduced calyx, bracts and
248
Pl. Ecol. Evol. 147 (2), 2014
Figure 7 – Distribution maps. A, Ixora masoalensis; B, Ixora pallens; C, Ixora pedalis; D, Ixora ripicola.
249
De Block, Eight new Ixora species from Madagascar
bracteoles. The two species differ in e.g. inorescence size,
articulation in the inorescence, corolla tube length, pedicel
length, presence/absence and size of bracteoles, size and po-
sition of stamens (table 3).
Other collections examined – Madagascar: Antsiranana: Sava,
Sambava, 21 May 1956, coll. ignot. 7963-RN (P); Sava, district
Sambava, canton Maroambihy, Andranomadiokely, 16 Jun. 1957,
coll. ignot. 9007-RN (P); Sava, Sambava, 21 May 1956, coll. ignot.
17593-SF (P); Sava, Ambatomenavava, Bezavona, forêt d’Ampira-
naomby, 25 Oct. 2010, Ravelonarivo & Raharivelo 3581 (BR, MO,
P, TAN); Sava, district Andapa, Parc National de Marojejy, near
entrance of park, 4 Feb. 2006, Razamandimbison & Ravelonari-
vo 654 (S, TAN). – Toamasina: Analanjirofo, Maroantsetra, Parc
National de Masoala, piste de Tampolo à l’ICOS II, Ambodifora-
ha, 22 Nov. 2001, Sauquet, Rabevohitra & Rakotonasolo 52 (P);
Analanjirofo, Masoala Peninsula, Ambanizana, trail A behind MBG
House, Jun. 1993, Zjhra & Hutcheon 323 (MO, P).
Ixora pallens De Block, sp. nov.
Ixora emirnensi similis ob inorescentias potius paucioras,
ovaria calycesque parvos, sed ab illa differt pedicellis lon-
gioribus (2–8 mm longis versus 0–3 mm), corollarum tubis
lobisque etiam longioribus (tubis 2–2.6 cm longis versus
1–1.5 cm; lobis 0.6–0.7 cm longis versus 0.3–0.5 cm) atque
foliarum laminis in sicco pallescentibus. – Type: Madagas-
car, Province Toamasina, Analanjirofo, Masoala Peninsula,
south trail, S of Androka River, climbing into hill SE of Am-
banizana, 30 Dec. 1990, Schatz & Modeste 3106 (holo-: MO;
iso-: P, TAN).
Shrub, 1–3 m tall; young internodes brown, smooth;
older internodes dark brown, smooth; all external parts
glabrous. Leaves: petioles 0.6–1.5 cm long; blades elliptic
or more rarely narrowly elliptic, 6.5–14 × 2.5–5 cm, pa-
pyraceous, drying pale greenish or pale brownish above,
somewhat paler below; apex acuminate with acumen
4–16 mm long; base cuneate or rarely acute; 10–20 pairs
of lateral nerves. Stipules caducous, sheath 3–4 mm long,
awn 0.5–1(–2) mm long. Inorescences pedunculate, lax,
with 20–30 owers, articulate except sometimes between
ovary and pedicel, 6–8 cm wide and 3–4.5 cm long; modied
inorescence-supporting leaves present, blades subsessile
(petioles 1–2 mm long), elliptic to oblong, 0.8–2 × 0.2–0.8
cm, base obtuse to rounded; peduncle 6–8 cm long; central
rst order axis 0.5–1.8 cm long, lateral rst order axes 1.5–
2.2 cm long; rst order bracts with stipular parts absent and
foliar parts triangular or mbriate, up to 2 mm long; higher
order bracts with stipular parts absent and foliar parts nar-
rowly triangular, up to 1 mm long. Ultimate ower triads:
owers pedicellate; pedicels 2–8 mm long but up to 15 mm
long in fruiting material, pedicels of central and lateral ow-
ers not differing much in length; bracteoles usually present,
opposite or sometimes sub-opposite at the base of the ovary
or somewhat lower on the pedicel, liform, 0.5–1 mm long.
Flowers: ower bud with obtuse apex; calyx 0.6–0.8 mm
long, tube 0.2–0.4 mm long, lobes broadly triangular or
broadly ovate, somewhat keeled, 0.3–0.5 mm long, apices
rounded; corolla tube 20–26 mm long; corolla lobes 6–7
mm long, c. 3 mm wide, apices blunt; stamens spreading at
anthesis, laments 0.5–1 mm long, anthers 2–2.5 mm long;
ovary bilocular, 0.8–1 mm long; style exserted c. 2 mm, stig-
matic lobes 0.8–1 mm long. Fruits slightly wider than high,
bilobed, 0.8–1.2 cm wide and 0.9–1 cm long; fruit wall thin;
seeds c. 8.5 mm long and 6.5 mm wide. Fig. 8.
Habitat – Low and mid-altitude evergreen humid eastern
forest, altitude: 0–700 m.
Distribution – Only known from the Masoala Peninsula
(province Toamasina). Fig. 7B.
Phenology – Flowers: December – January; fruits: June –
August.
Living colours – Peduncle, inorescence axes, pedicels,
bracts and bracteoles green; corolla white; ovary and calyx
green; fruits red.
Critical remarks – The species epithet refers to the pale
colour of the dried specimens. – Another species with rela-
tively small leaves, pedunculate inorescences with a mod-
erate number of owers and relatively short corolla tubes,
I. pallens distinguishes itself by the pale drying colour of the
leaves, the not-discolourous higher order venation, the ob-
tuse ower bud and the relatively long pedicels (table 2).
Other collections examined – Madagascar: Toamasina: Anal-
anjirofo, Parc National de Masoala, sur la route d’Ambanizana
à Analambolo, 25 km N de la ville d’Ambanizana, c. 6 km NE
d’Ambanizana, v. Maroantsetra, 24 Jan. 1996, Aridy, Rahajasoa &
Moïse 76 (MO, P); Analanjirofo, Ambanizana, Masoala Peninsula,
trail A behind MBG house, Jun. 1993, Zjhra & Hutcheon 325 (MO,
P); Analanjirofo, Ambanizana, Masoala Peninsula, along Androka
River, S of MBG house, Jun. 1993, Zjhra & Hutcheon 377 (MO);
I. masoalensis I. crassipes
Leaf apex obtuse to acute shortly acuminate, acumen 0.5–1 cm long
Leaf base attenuate cuneate, acute, rounded
Inorescences articulate throughout,
1.5–6 cm wide, 2–4 cm long
not articulate just below the ovary,
9–13 cm wide, 6–9 cm long
Pedicel length 0–1(–1.5) mm (2–)5–15 mm long
Bracteoles usually present, liform, up to 1 mm long usually absent, if present,
then liform, < 0.5 mm long
Calyx with triangular lobes, 0.3–0.6 mm long truncate
Corolla tube 10–12 cm long 17–22.5 cm long
Stamens erect at anthesis, sessile, anthers 8–11 mm long spreading at anthesis, laments 2–3 mm long,
anthers 6–8 mm long
Table 3 – Distinguishing characters for Ixora masoalensis and I. crassipes.
250
Pl. Ecol. Evol. 147 (2), 2014
Figure 8 – Ixora pallens: A, owering branch; B, ultimate ower triad (corollas removed); C, bracteole, ovary and calyx; D, corolla, stamens,
style and stigma; E, fruit (A–D, from Schatz & Modeste 3106; E, from Zjhra & Hutcheon 391). Drawn by Antonio Fernandez.
Analanjirofo, Andronobe, Masoala Peninsula, transect 2, 0–3 km E
from coast, Jun.–Aug. 1993, Zjhra & Hutcheon 391 (MO, P).
Ixora pedalis De Block, sp.nov.
Ab plerusque alteris speciebus Madagascariensibus habitu
suffruticoso (plantae solummodo 25 cm altae) et inores-
centiis paucioris primo adspectu differt; praeterea foliorum
laminis potius magnis [(5–)6.8–15 × 1.5–5.5 cm], oribus
parvis (tubis 0.4–1.2 cm longis) et staminum lamentis lon-
gis (2 mm longis) singularis. – Type: Madagascar, Province
Antsiranana, Sava, Réserve Naturelle de Marojejy, western
slopes of Montagne de Beondroka, 23–24 Oct. 1989, Miller
& Randrianasolo 4397 (holo-: MO; iso-: K, P, TAN).
Small subshrub up to 25 cm tall; young internodes brown,
smooth; older internodes brown to dark brown, somewhat
corky; all external parts glabrous, except rarely the inores-
cence axes. Leaves: petioles 0.2–1 cm long; blades elliptic
or narrowly elliptic, more rarely somewhat obovate or ovate,
(5–)6.8–15 × 1.5–5.5 cm, papyraceous to subcoriaceous,
drying pale or yellowish green, green or brown, somewhat
251
De Block, Eight new Ixora species from Madagascar
paler below; apex acuminate with acumen up to 2 cm long;
base cuneate to attenuate or rarely acute; 10–16 pairs of lat-
eral nerves. Stipules caducous, sheath 1.5–3 mm long, awn
1–1.5 mm long. Inorescences sessile, compact to lax, with
(3–)5–18 owers, not articulate throughout, 0.7–3.5 cm wide
and 0.5–3 cm long; modied inorescence-supporting leaves
absent; axes glabrous or more rarely sparsely pubescent with
very short hairs; central rst order axis 0–1.5 cm long, lateral
rst order axes 0–2 cm long; rst order bracts with stipular
parts fused into a blade with a central awn and foliar parts
absent or forming small leaves; higher order bracts rarely
similar to rst order bracts but reduced, but usually with stip-
ular parts absent and foliar parts triangular and vaulted, nar-
rowly triangular, somewhat mbriate or linear, up to 2 mm
long. Ultimate ower triads: owers (sub)sessile to shortly
pedicellate; pedicels 0–3 mm long, pedicels of central ow-
ers (up to 0.5 mm long) shorter than those of lateral ow-
ers (0.5–3 mm long); bracteoles usually absent, if present
then opposite at the base of the ovary, narrowly triangular
or liform, up to 1 mm long. Flowers: ower bud with ob-
tuse apex; calyx c. 1 mm long, tube 0.3–0.5 mm long, lobes
variable in shape, triangular, ovate or truncate with central
acumen, 0.3–0.5 mm long, apices obtuse or acute, smaller
interstitial lobes often present; corolla tube 4–12 mm long;
corolla lobes 3.5–6 mm long, c. 2 mm wide, apices obtuse;
stamens spreading at anthesis, laments c. 2 mm long, an-
thers c. 2.5 mm long; ovary bilocular, 0.75–1 mm long; style
exserted 2–4 mm, stigmatic lobes 0.75–1.5 mm long. Fruits
subglobose, 0.8–1 cm in diameter when bilocular, but ovoid,
0.5–0.6 cm wide, 0.8–1 cm long when unilocular; fruit wall
thin; seeds c. 0.7 cm long, c. 0.4 cm wide. Fig. 9.
Habitat – Lowland and mid-altitude humid eastern forest,
altitude: 150–850 m.
Distribution – North-eastern Madagascar: known from
Masoala Peninsula and the Sambava-Andapa-Marojejy re-
gion (provinces Antsiranana and Toamasina). Fig. 7C.
Phenology – Flowers: October – November; fruits: April –
July.
Living colours – Inorescence axes green tinged red; ovary
and calyx greenish or whitish tinged red; corolla white, white
tinged pink or pink; stamens white; fruits red.
Critical remarks – Ixora pedalis shows a large variation in
the inorescence structure, from compact to lax. Inores-
cence axes may be completely reduced and all owers ses-
sile in certain specimens, whereas others have inorescence
axes up to 2 cm long. – The inorescence is not articulate
throughout, with articulation often absent in the ultimate
ower triads. Usually, lateral owers are articulate, central
ones are not. – The subshrub habit together with the few-
owered inorescences renders I. pedalis unique amongst
the Madagascan Ixora species. The only other species with
a subshrub habit have uniorous inorescences: I bemangi-
diensis Guédès and I. reducta Drake ex Guédès (De Block
2008).
Other collections examined – Madagascar: Antsiranana: Sava,
Analamanara, près du village de Tsaratanana, entre Antsirabe-Nord
et Sambava, 24 Oct. 1966, Capuron 24910-SF (P, TEF); Sava, can-
ton Doany, district Andapa, 29 Apr. 1957, coll. ignot. 8853-RN
(TEF); Sava, sous-préfecture d’Andapa, commune Doany, fok. Bet-
somanga, versant NW du Marojejy, 0,2 km E du camp 1, au point
003, 16 Oct. 2001, Gautier, Ravelonarivo & Andriamparany 3837
(BR, G). – Toamasina: Analanjirofo, Maroantsetra, SE of Ambani-
zana, along ridge SE of Androka River, SE of Maroantsetra, 15 Oct.
1986, Lowry, Rakotozafy & Nicoll 4128 (MO, TAN); Analanjirofo,
Masoala Peninsula, Ambanizana, south trail, S of Androka River
climbing into hills SE of Ambanizana, 1 Nov. 1992, Schatz, van
der Werff, Gray & Razamandimbison 3407 (MO); Analanjirofo,
Masoala Peninsula, Point Tompolo, Jul. 1993, Zjhra & Hutcheon
543 (MO).
Ixora ripicola De Block, sp. nov.
Corollis longis et fructibus magnis Ixora guillotii similis, sed
differt fructuum forma subspherica et pericarpio percrasso,
stipularum brevioribus (vaginae 1.5–3 mm longis versus
3–6 mm; aristae 1–1.5 mm longis versus 0.5–5 mm), brac-
teolarum brevioribus [≤ 1 mm longis versus 1–2(–3) mm],
lorum longioribus (1.5–3 mm longis versus 0.5–0.75 mm)
et corollarum lobis brevioribus [0.6–0.8(–0.9) cm longis ver-
sus 1–1.6 cm]. – Type: Madagascar, Province Antsiranana,
Diana, Réserve Naturelle Intégrale d’Ankarana, 18 May
1987, Nicoll & Abraham 675 (holo-: MO; iso-: BR, K, P, S,
TAN, WAG).
Tree or rarely shrub, up to 20 m tall, dbh up to
35(–80) cm; internodes often short, especially below the in-
orescences; young internodes brown, smooth; older inter-
nodes brown, somewhat corky; all external parts glabrous
except for inorescence axes and pedicels in some speci-
mens. Leaves: petioles 0.4–1 cm long; blades narrowly ellip-
tic, narrowly obovate or narrowly ovate, more rarely elliptic,
6–18 × 1.5–4 cm, coriaceous or subcoriaceous, drying brown
above, somewhat paler below; apex acute or shortly acumi-
nate, acumen up to 1 cm long; base cuneate, acute or obtuse,
often somewhat unequal; 12–20 pairs of lateral nerves. Stip-
ules: sheath 1.5–3 mm long, awn 1–1.5 mm long. Inores-
cences sessile or more rarely shortly pedunculate, lax, with
(15–)30–100 owers, articulate throughout, 2.5–9 cm wide
and 3.5–8.5 cm long; modied inorescence-supporting
leaves absent; peduncle 0.5–2 cm long; axes and pedicels
glabrous or sparsely to moderately pubescent with short erect
hairs; central rst order axis 0.5–2.2 cm long, lateral rst
order axes 1.2–3.5 cm long; rst (and rarely second) order
bracts with stipular parts forming a low sheath with a cen-
tral awn and foliar parts forming leaves similar in shape and
size to vegetative leaves (up to 3 × 8 cm); higher order bracts
with stipular parts absent, foliar parts broadly triangular and
vaulted, up to 3 mm long. Ultimate ower triads: owers
sessile to pedicellate; pedicels 0-8 mm long, central ow-
ers (sub)sessile (pedicels 0–1 mm long) and lateral owers
pedicellate (pedicels 1–7 mm long) but pedicels of central
and lateral owers 3–8 mm long in case of reduction; brac-
teoles usually absent on central owers but present on lateral
ones, opposite at the base of the ovary, broadly triangular,
up to 1 mm long. Flowers: ower bud with acute to obtuse
apex; ovary and calyx often drying dark brown or blackish
with calyx lobes or margins of calyx lobes paler brown; ca-
lyx 1–1.5 mm long, tube up to 0.5 mm long, lobes triangular
or broadly triangular, 0.75–1(–1.5) mm long, apices obtuse
to rounded; corolla tube (27–)34–90 mm long; corolla lobes
6–8(–9) mm long, 3–4 mm wide, apices obtuse to rounded;
252
Pl. Ecol. Evol. 147 (2), 2014
Figure 9 – Ixora pedalis: A, owering plant; B, ultimate ower triad (corollas removed); C, bracteole, ovary and calyx; D, corolla, stamens,
style and stigma (A–D, from Miller & Randrianasolo 4397). Drawn by Antonio Fernandez.
253
De Block, Eight new Ixora species from Madagascar
Figure 10 – Ixora ripicola: A, owering branch; B, leaf; C, ultimate ower triad (corollas removed); D, bracteole, ovary and calyx; E, fruit;
F, transverse section of fruit showing massive fruit wall (A, C & D, from Andrianantoanina et al. 805; B, from Ursch 244; E & F, from coll.
ignot. 10665-SF). Drawn by Antonio Fernandez.
stamens spreading at anthesis, laments 1.5–3 mm long, an-
thers 5–6 mm long; ovary bilocular, 1.5–2 mm long; style
exserted 4–7 mm, stigmatic lobes 1.5–2 mm long. Fruits sub-
globose, 2.5–3 cm in diameter; fruit wall 0.5–1 cm thick (in
dry fruits); seeds 1–1.2 cm long, 0.6–0.7 cm wide. Fig. 10.
Habitat – Dry semi-deciduous or deciduous western forest,
also in sublittoral forest; often on a river bank or bordering
a streambed; reported from very different soil types such as
sand, limestone, basalt, laterite and clay, altitude: 50–900 m.
Distribution – Western Madagascar; from the region of Mo-
rondava to the northernmost tip of the island (provinces Ant-
siranana, Mahajanga and Toliara). Fig. 7D.
Phenology – Flowers: May – July, Humbert 11421 from To-
liara owers in October; fruits: July – November.
254
Pl. Ecol. Evol. 147 (2), 2014
Living colours – Inorescence axes and pedicels green;
corolla white or white tinged pink, turning yellow with age;
fruits red. Flowers fragrant.
Vernacular names – Hazomena; hazompanenitra; mena-
hatra; motrobeantinianana; sohiala; tsintsarotsano, tsont-
sarakefotsy; vahirota.
Uses – Construction wood (poles for fences, huts, etc.).
Critical remarks – The name I. ripicola was rst used in P,
but remained unpublished; its author is unknown. – I. ripi-
cola possesses large subspherical fruits with a massive fruit
wall, similar to the fruits encountered in some Mascarene
Ixora species such as I. borboniae Mouly & B.Bremer in
which the number of locules vary between three and seven
(Verdcourt 1989, as Myonima obovata Lam.). – I. ripicola
ressembles I. cremixora Drake and I. guilotii Hochr. by the
large, lax or relatively lax inorescences [2.5–12.5(–30) cm
wide, 3–12(–20) cm long] and the owers of similar length
[(2.7–)3.4–9 cm long]. I. ripicola and I. cremixora have the
same distribution range and both occur in lowland to mid-
altitudinal semi-deciduous or deciduous dry western forest.
But the two species differ by habit, pedicel length, presence/
absence and size of bractoles, size and shape of calyx lobes,
lament length, fruit size and thickness of fruit wall (table
4). I. guillotii occurs in littoral and sublittoral forest, mostly
in eastern Madagascar. This species differs from I. ripicola
by habit, pedunculate inorescences subtended by modied
inorescence-supporting leaves, shape and size of bractoles
and calyx lobes, lament length, size and shape of fruit and
thickness of fruit wall (table 4).
Other collections examined – Madagascar: Antsiranana: Diana,
Réserve Spéciale d’Ankarana, env. 108 km SW d’Antsiranana par
route, W de Mahamasina, 31 May 1995, Andrianantoanina, Beza-
na, Zjhra & Hutcheon 805 (BR, MO, P, TAN); Diana, Andavaka-
omby, canton Anivorano-Nord, 30 Aug. 1954, coll. ignot. 10665-SF
(P, TEF); Diana, exploitation Walzer, Tsarakibany, canton Anivora-
no-Nord, 17 Jun. 1955, coll. ignot. 15054-SF (BR, P, TEF); Diana,
jardin botanique 8, Ambondromifely, canton Anivorano-Nord, 23
Nov. 1955, coll. ignot. 15190-SF (BR, P, TEF); Diana, Anjanikely,
Andriaabe, 23 Sep. 1980, coll. ignot. 29950-SF (TEF); Diana,
forêt d’Ankarana, Ratsalahimango, v. Ambilobe, 20 May 1987,
coll. ignot. 31580-SF (TEF); Diana, Réserve Spéciale d’Ankarana,
22–26 Nov. 1992, Malcomber, Leeuwenberg, Van Bergen, Andria-
tiana & Randriamamapionona 1893 (BR, K, MO, P, TAN, WAG);
Sava, v. Vohemar, commune rurale Nossi-Be, fok. Anjiabe, forêt
d’Analabe, 11 May 2004, Rabehevitra, Razakamalala & Mathie
962 (BR, MO); Diana, v. Diego II, commune Ramena, fok. An-
davakoera, forêt d’Andranonakomba, montagne des Français, 8
Sep. 2004, Randrianaivo, Rakotondrajaona, Razatsalama, Ra-
kotondrafara, Benjara & Be 1083 (K, MO); Sava, v. Vohemar,
commune rurale Nossi-Be, forêt littorale d’Analabe près du vil-
lage d’Anaborano et du Lac Sahaka, 10 Jul. 2003, Razakamalala,
Rabevehitra & Rakotomamonjy 520 (BR, K, MO); Sava, v. Vo-
hemar, commune rurale Nossi-Be, forêt littorale d’Analabe près du
Lac Sahaka, 13 May 2004, Razakamalala, Rabevehitra & Mathieu
1244 (BR, MO); Diana, N de Joffreville, s.d., Ursch 244 (P). – Ma-
hajanga: Boeny, Réserve Naturelle Intégrale 8, Namoroka, An-
dranomavo, district Soalala, 29 Oct. 1952, coll. ignot. 4622-RN
(TAN); Soa, forêt Tsangitangina, Ambarijeby, canton Befandriana,
district Befandriana-Nord, 7 Sep. 1956, coll. ignot. 16089-SF (BR,
P); Soa, forêt entre les villages de Mevahiaka et Tsarahonenana,
village le plus proche Mevahiaka, canton Tsarahonenana, district
Refaridiana, 19 Oct. 1960, coll. ignot. 19800-SF (BR, P, TEF); So-
a, Analazezy, village Ankobakobaka, canton Befandriana-Nord,
28 Jul. 1970, coll. ignot. 30039-SF (P, TEF); Boeny, rive gauche de
la Mahavahy, environs de Itampika, Ambongo, Aug. 1904, Perrier
de la Bâthie 1753 (P); Boeny, plateau d’Antanimena, Jun. 1906,
Perrier de la Bâthie 3701 (P); Boeny, Ambongo, s.d., Perrier de la
Bâthie 3820 (P); Vakinankaratra, Belambo, environs Maevatanana,
Jul. 1900, Perrier de la Bâthie 3869 (BR, P). – Toliara: Menabe,
forêt de Marofandilia entre Morondava et la Tsiribihina, Oct. 1933,
Humbert 11421 (P) & 11422 (P). – Without locality: s.d., Homolle
24 (BR, P).
I. ripicola I. cremixora I. guilotii
Habit
Tree or rarely shrub,
up to 20 m tall,
dbh up to 35(–80) cm
Shrub or small tree,
2–10 m tall
Shrub or rarely small tree,
up to 5 m tall
Leaf blades 6–18 × 1.5–4 cm 5–23(–30) × 1.5–6(–8) cm 11–35 × 3–8 cm
Peduncle length 0–2 cm 0 cm (0.5–)1.5–6.5 cm
Modied inorescence-
supporting leaves absent absent 1–3 pairs
Pedicel length 0–8 mm (3.5–)6–20 mm 0–10 mm
Presence of bracteoles usually present
in lateral owers often absent usually present
in lateral owers
Bracteoles broadly triangular,
up to 1 mm long
liform or narrowly triangular,
up to 1 mm long
narrowly triangular,
1–2(–3) mm long
Calyx lobes
lobes triangular
or broadly triangular,
0.75–1(–1.5) mm long
lobes shortly triangular,
< 0.3 mm long
lobes triangular
or broadly triangular,
0.75–2.5(–3) mm long
Filament length 1.5–3 mm long 1–1.5 mm long 0.5–0.75 mm
Fruit size 2.5–3 × 2.5–3 cm 1–1.2 cm wide,
0.8–1 cm long
1.2–1.5 cm wide,
1.4–1.7 cm long
Fruit wall thick (0.5–1 cm in dry fruits) thin thin
Table 4 – Distinguishing characters for Ixora ripicola, I. cremixora and I. guilotii.
255
De Block, Eight new Ixora species from Madagascar
ACKNOWLEDGEMENTS
The herbarium curators of BR, G, K, MO, P, TAN, TEF,
UPS, WAG and Z are thanked for providing plant material
and for help extended during study visits. Prof. Dr. Elmar
Robbrecht is acknowledged for writing the Latin diagnoses. I
thank Ms. Mia Scheerlinck, Mr. Antonio Fernandez and Mr.
Roger Lala Andriamiarisoa for making the line drawings and
Ing. Marcel Verhaegen and Mr. Sven Bellanger for making
the distribution maps. Field work was conducted within the
framework of the Madagascar Research and Conservation
Program of Missouri Botanical Garden. I thank Dr. Lowry
for giving access to the MBG facilities. The MBG ofce staff
in Antananarivo is gratefully acknowledged for their hos-
pitality and help. I extend special thanks to Dr. Franck Ra-
kotonasolo, who provided invaluable help during the eld-
work. Dr. Steven Dessein, Dr. Inge Groeninckx, Dr. James
Tosh and Ms. Tiana Randriamboavonjy participated in part
of the eld work. I am grateful to Madagascar National Parks
(previously known as Association Nationale pour la Ges-
tion des Aires Protégées, ANGAP), the Ministère des Eaux
et Forêts and the Parc Botanique et Zoologique de Tsimba-
zaza (PBZT) for permission to collect in protected areas. The
eldwork was nancially supported by the Fund for Scien-
tic Research-Flanders (research project G.0250.05) and the
Percy Sladen Memorial Fund.
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Communicating Editor: Elmar Robbrecht.
