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Journal homepage: http://www.journalijar.com
INTERNATIONAL JOURNAL
OF ADVANCED RESEARCH
RESEARCH ARTICLE
A TAXONOMIC REVISION OF EXACUM L. (GENTIANACEAE - EXACEAE) IN SOUTH INDIA.
*
Shahina P.M. & Santhosh Nampy.
Department of Botany, University of Calicut, Kerala, India.
Manuscript Info
Abstract
Manuscript History:
The paleotropic genus Exacum (Gentianaceae: Exaceae) is revised for South
India, recognizing twelve species and one variety. E. wightianum var.
uniflorum is synonymized under E. klackenbergii while E. grande is reduced
to the variety of E. tetragonum. Nine out of thirteen taxa (75%) are endemic
to the southern Western Ghats while one is critically endangered (E.
travancoricum), one endangered (E. tetragonum), one vulnerable (E.
courtallense) and six are rare (E. anamallayanum, E. atropurpureum, E.
klackenbergii, E. lawii, E. tetragonum var. grande and E. wightianum). The
problems in the typification of E. courtallense var. laxiflorum are dicussed.
Detailed taxonomic descriptions, photoplates and a key to the identification
of species in South India are provided.
Received: 14 January 2016
Final Accepted: 16 February 2016
Published Online: March 2016
Key words:
Exacum, Exaceae, Gentianaceae,
South India.
*Corresponding Author
Shahina P.M.
Copy Right, IJAR, 2016,. All rights reserved.
Introduction
The name Exacum was first used by Linnaeus (1747 a, b). But even before Linnaeus, Plukenet (1700) in his
Phytographia illustrated the species now known as E. pedunculatum. Linnaeus in 1753, described two species of
Exacum, namely, E. sessile and E. pedunculatum as well as Chironia trinervia (= Exacum trinervium). Though
different authors subsequently described several species of Exacum from South America, Africa, Europe, North
America and Asia, none of these are now referred to as Exacum. Roxburgh (1814, 1820) described five new species
and Wallich (1831) one species of Exacum from India. Among them, except E. teres and E. tetragonum, all others
became synonyms.
Grisebach (1838) recognized 13 species of Exacum in his Genera et species Gentianearum. More Asian species were
added in the mid to late 1800s by various authors such as Don (1837), Arnott (1839), Grisebach (1845), Thwaites
(1860), Beddome (1874) and Clarke (1883).
Klackenberg (1985) monographed Exacum and recognised 65 species in two sections. The sect. Exacum includes all
Asiatic species (21 sp. and 1 var.), majority of them occur in India and Sri Lanka. He (l.c.) created a new section
Africana to accommodate all the 44 African species distributed mainly in Madagascar, Socotra and African
mainland. Thulin (2001) reported three species from southern Arabian peninsula and the Island of Socotra. Based on
morphological and molecular data, Klackenberg (2006) transferred all species of Cotylanthera, which is represented
by four saprophytic species, to Exacum.
At present, Exacum is represented by seventy species and one variety including four new combinations from
Cotylanthera and two recently described species E. klackenbergi (Gopalan, 2002) and E. darae (Hul, 2010). In the
present treatment, E. grande is reduced to a variety of E. tetragonum. Madagascar is presently considered to be the
center of species diversity with 38 species and Western Ghats is the second most species-rich area with 12 species
and one variety.
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Materials and Methods
Specimens for the present study were collected through field trips across South India. Voucher specimens were
deposited at CALI. Morphological descriptions were recorded after consulting live and herbarium specimens.
Herbarium materials from BLAT, BSD, BSI, CAL, CALI, DD, DEV, FRC, JCB, KFRI, MH, RHT, RRLB, SNC,
SKU and TBGT were examined (abbreviations follow Holmgren et al. (1990)). Identification of each species was
done in consultation with type and protologue. Type images of species were procured from the virtual data bases of
foreign herbaria like BM, E, G-DC, HAL, K, K-W, L, LINN, S, U and W. The details on chromosome number,
distribution and uses were procured from literature and colour photographs were prepared using Leica EZ4HD
Stereo Microscope.
Results & Discussion
Systematic Treatment
Exacum L., Sp. Pl. 1: 122. 1753; Klack., Opera Bot. 84:1. 1985. Type: Exacum sessile L.
Chondropsis Rafin., Fl. Tellur 3: 29. 1836. Type: C. trinervis (L.) Raf. (= Exacum trinervium (L.) Druce).
Paracelsea Zoll. & Moritzi, Natuur. Geneesk. Arch. Ned. Indie 2: 18. 1845. Type: P. amoena Zoll. & Moritzi
Annual, erect or trailing, glabrous herbs or subshrubs. Stems terete, 4-angular, 4-winged or 4-lineolate. Radical
leaves rosette, spathulate; cauline leaves sessile-subsessile or petiolate, ovate-lanceolate, elliptic, 3–5-nerved at base;
acute or acuminate at apex, amplexicaul, cuneate or truncate at base. Cymes axillary or terminal, lax or dense,
dichasial, 1–5 flowered. Flowers 4–5 merous, blue-violet or white, tubular; bracts foliaceous. Calyx green,
persistent, tubular, winged or wingless; lobes 4–5, ovate-lanceolate, 3-nerved. Corolla tubular, salver shaped or
subrotate, contorted in bud; lobes 4–5, ovate-elliptic, oblong or lanceolate, 3-nerved, acute at apex. Stamens-4–5,
isomorphic; filaments linear, anthers oblong, tetragonal, declinate, basifixed, emarginate at base, recurved or erect,
dehiscing by apical pores or later by lateral slits. Ovary bicarpellary, syncarpous, bilocular, globose; style filiform,
declinate; stigma subcapitate, 2-lobed. Capsules globose, dehisces longitudinally. Seeds yellowish-reddish brown,
numerous, minute; testa scorbiculate.
Distribution: A paleotropical genus found in tropical regions of Africa, Asia and Madagascar (Klackenberg, 2006).
Habitat: In grasslands, road side cuttings, rock crevices and forests, from sea level to c. 2800 m elevation. Most
species occur in lowland and montane rainforests, although they usually grow in full sun.
Etymology: The name „Exacum‟ is derived from its property of expelling pollens through apical pores of anthers.
Key to the species of Exacum
1a. Flowers tetramerous .................................................................................................... ……………. 2
1b. Flowers pentamerous ....................................................................................................................... 7
2a. Leaves with a distinct petiole; calyx wings enlarging in fruit, with prominent
veins. ................................... ………………………………………………………….7. E. petiolare
2b. Leaves sessile-subsessile; calyx wings not enlarging in fruit, without
prominent veins………………………………………………………………………...………..3
3a. Leaf base not amplexicaul; petals bicoloured ...................................................... 10. E. tetragonum
3b. Leaf base amplexicaul; petals single coloured ................................ 11. E. tetragonum var. grande
4a. Calyx winged ................................................................................................................................... 5
4b. Calyx without wings ........................................................................................................................ .6
5a. Cymes never clustered, often solitary or 1–3 flowered ...............................................8. E. pumilum
5b. Cymes often clustered, 1–5 flowered. .............................................................. 6. E. pedunculatum
6a. Flowers sessile-shortly pedicellate, pedicels 0.5–1.5 cm long; central flower
drooping .......................................................................................................................... 9. E. sessile
6b. Flowers always long pedicellate, pedicels 2–4.5 cm long; flowers not drooping .............................. .
…. . …………………………………………………………………………………….5. E. lawii
7a. Stems 4-angular, winged; anthers papillate; fruits drooping ............................... .13. E. wightianum
7b. Stems terete, woody; anthers not papillate; fruits not drooping. ....................................................... 8
8a. Leaves petiolate .................................................................................................. 4. E. klackenbergii
8b. Leaves sessile-subsessile .................................................................................................................. 9
9a. Leaf base amplexicaul; lamina coriaceous ...................................................... 1. E. anamallayanum
9b. Leaf base not amplexicaul; lamina non coriaceous ........................................................................ 10
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10a. Anthers rectangular ....................................................................................... 2. E. atropurpureum
10b. Anthers bottle shaped ................................................................................................................... 11
11a. Habit cushion type; leaves succulent ............................................................ 12. E. travancoricum
11b. Habit non cushion type; leaves not succulent ......................................................3. E. courtallense
1. Exacum anamallayanum Bedd., Icon. Pl. Ind. Or. 1: 33. t. 154. 1874; Klack., Opera Bot. 84: 69. 1985;
Sasidh., Biodivers. Doc. Kerala 6: 297. 2004. Exacum atropurpureum var. anamallayanum (Bedd.) C.B. Clarke in
Hook.f., Fl. Brit. India 4: 97. 1883. Type: Anamallays, s. die, Beddome 5332 (lecto, BM!).
Exacum beddomei C.B. Clarke, J. Linn. Soc., Bot. 14: 427. 1875. Type: Pulney hills, s. die, Beddome 49 (lecto,
CAL!).
Exacum saulierei Dunn, Bull. Misc. Inform. Kew 30. 1914. Type: South India, Madura district, Sauliere 69 (lecto,
K!).
Figure 1
Herbs, 35–90 cm tall. Stems terete but 4-angular when young, woody, moderately-much branched basally and
apically. Leaves sessile; lamina broadly ovate-lanceolate, 3–8 × 1.5–4 cm, 3–5-nerved at base, coriaceous, acute or
mucronate at apex, amplexicaul at base. Cymes terminal or axillary, 1–5 flowered; bracts ovate, 0.3–2 × 0.2–1 cm;
pedicels 1–4 cm long. Calyx green, persistent but not accrescent in fruit, dorsally winged; wings thick, without
prominent veins, 1–1.5 mm wide, narrow at apex, truncate at base; lobes-5, ovate-lanceolate, 7–15 × 2–3.5 mm,
acute-acuminate at apex. Corolla tube white, 0.5–0.8 cm long; lobes-5, violet, yellow at throat, obovate-elliptic, 2–4
× 0.5–1.8 cm, cuspidate. Stamens-5; filaments short, pale green-yellow, 1.5–3 mm long; anthers orange yellow,
linear, erect, sagittate, 5–12 mm long, papilla indistinct, seen on the dorsal side near the apex; dehiscence through
apical pores, later widen to slits. Ovary green, ovate, 0.25–0.8 × 0.2–0.3 cm; style greenish white, longer than the
stamens, 0.5–2.5 cm long, deflexed; stigma simple, rounded, faintly 2-lobed; lobes 0.1 cm long. Capsules brown,
oblong-ovate, 1–2 × 0.2–0.35 cm, unilocular, dehisces longitudinally. Seeds many, irregular or tetrahedral with
shallowly sunken sides, 0.25–0.4 × 0.1–0.2 mm; testa brown.
Chromosome number: Not reported.
Flowering & fruiting: March–July.
Habitat: It is a higher elevation plant (1700–2700 m alt.) found in grasslands.
Distribution: This is rare and endemic to southern Western Ghats, occuring in Anamalais, Munnar and Palnis.
Specimens examined: Kerala, Idukki district, Anamudi hills, 31.03.1912, C.E.C. Fischer 3314 (CAL), Ibid.,
19.03.1986, B. Gurudev Singh 12209 (FRC); Devikolam, 17.04.1966, B.V. Shetty 2525 (MH); Munnar, Silent
Valley, 13.04.2013, A.J. Robi & K.M. Manudev 4982, Ibid., 02.05.2013, P.M. Shahina & Santhosh Nampy 4985
(CALI). Tamil Nadu, Dindigul district, Kodaikanal, 29.07.1913, Sauliere 817 (CAL); Palni hills, s. die, Beddome
s.n., Ibid., 02.1898, A.G. Bourne 321 (CAL), Ibid., 05.06.1899, J.S. Gamble s.n. (MH). Theni district, High wavy
mountains, 05.1917, Blatter & Hallberg 5 (CAL).
Notes: Beddome (1874) described E. anamallayanum as the loveliest species of this genus. It is close to E.
atropurpureum but differs by its broadly ovate, coriaceous, distinctly amplexicaul leaves and cuspidate petals.
2. Exacum atropurureum Bedd., Icon. Pl. Ind. Or. 1: 24. pl. 119. 1874; Klack., Opera Bot. 84: 71. 1985.
Lectotype: Icon. Pl. Ind. Or. 1: 24. pl. 119. 1874.
Figure 2
Herbs, 20–65 cm tall. Stems 4-lineolate at young but terete and woody when mature, moderately branched basally
and apically; internodes usually shorter than the leaves. Leaves sessile, stem clasping but not amplexicaul; lamina
broadly ovate-suborbicular or elliptic, 3–10 × 1.5–3 cm, 3–5 nerved at base, coriaceous, acuminate at apex, rounded
at base. Cymes terminal or axillary, 1–5 flowered; bracts ovate, 1–1.5 × 0.3–0.6 cm; pedicels 1–3 cm long. Calyx
green, edges hyaline, persistent, prominently winged; wings without prominent veins , not accrescent in fruit,
semicordate, 2–4 mm wide; lobes-5, ovate, 10–15 × 2–3.5 mm, acuminate at apex. Corolla tube pale blue-white,
0.4–0.7 cm long; lobes-5, blue-violet, ovate-oblong, 1.5–3.5 × 0.5–1.3 cm, acute-acuminate at apex. Stamens-5;
filaments short, pale green-yellow, 1.5–2.5 mm long; anthers orange yellow, linear-ovate, erect, sagittate, 6–10 mm
long, dehiscence through apical pores later widen to slits, small papilla present near the apex on the dorsal side.
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Figure 1:. Exacum anamallayanum Bedd.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened; E. Apical
pore of stamens; F. Gynoecium; G. Fruit; H. Seeds (from Robi A.J. & Manudev K.M. 4982).
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Ovary green, ovate, 0.25–0.5 × 0.2–0.3 cm; style greenish white, often longer than the stamens, 0.4–1.2 cm long,
deflexed; stigma simple, rounded, faintly 2-lobed; lobes c. 0.1 cm long. Capsules brown, elliptic-oblong, 1–2.5 ×
0.2–1 cm. Seeds many, irregular or tetrahedral with shallowly sunken sides, 0.2–0.4 × 0.1–0.25 mm; testa brown.
Chromosome number: 2n = 34 (Mallikarjuna et al. 1987).
Flowering & fruiting: January–December.
Habitat: In higher elevation grasslands.
Distribution: It is a rare species endemic to southern Western Ghats. Klackenberg (1985) recorded it as a local
endemic, restricted to Tirunelveli hills, but it also occurs in Dindigul, Idukki and Wayand districts.
Specimens examined: Kerala, Idukki district, Kurisumala, 20.12.1993, E.S. Santhosh Kumar 19157 (TBGT).
Thiruvananthapuram district, Chimunji, 14.03.2007, A. Nazarudheen 34199 (TBGT), Ibid., 11.04.1898, Beddome
935 (CAL). Wayanad district, Periya, Gurukula Botanical Sanctuary 14.01.2013, P.M. Shahina & Santhosh Nampy
4993 (CALI). Tamil Nadu, Dindigul district, Kodaikanal, Silver Cascade, 14.02.1974, Beddome 2692 (CALI),
Ibid., 1940, s.coll. 2733 (RHT); s.loc., 14.02.1974, B.K. Nayar & K. Unnikrishnan s.n. (CALI). Kanyakumari
district, Kuttiyar, 25.05.1988, R. Gopalan 88642; Upper Kodayar, 30.09.1980, A.N. Henry 68873 (CAL).
Tirunelveli district, Tirunelveli, 22.05.1908, C.A. Barber 289 (CAL).
Notes: E. atropurpureum is closely allied to E. anamallayanum but differs in the texture and clasping nature of
leaves, prominently winged calyx and ovate-oblong petals. Klackenberg (1985) remarked that E. atropurpureum
exhibits wide variation in leaf shape and size and considered them as normal infraspecific variations. We have seen
4-lineolate condition in younger plants but never petiolate leaves.
3. Exacum courtallense Arn., Ann. Sci. Nat., Bot. sér. 2, 11: 175. 1839; Klack., Opera Bot. 84: 66. 1985.
Type: Courtallum, 1835, Wight 553 (lecto, E!).
Exacum courtallense var. laxiflorum Gamble, Fl. Madras 2: 873. 1923; A.N. Henry & Swamin., J. Bombay Nat.
Hist. Soc. 80: 458. 1983. Type: Travancore, 1873, Beddome s.n. (lecto, MH!).
Exacum courtallense var. boneccordense (as bonnecordensis) M. Mohanan in M. Mohanan & A.N. Henry, Fl.
Thiruvananthapuram 305. 1994. Type: Thiruvanathapuram district, Bonacaud, s. die, M. Mohanan 63225 (holo,
CAL).
Figure 3
Herbs, 25–70 cm tall. Stems pale green, terete, woody, 4-lineolate when young, dichotomously much branched
basally and apically; internodes usually shorter than the leaves. Leaves sessile-subsessile, waxy coated; lamina
oblong-lanceolate, 2–7 × 1–4 cm, 3-nerved at base, acuminate at apex, cuneate at base. Cymes terminal or axillary,
1–5 flowered; bracts lanceolate, 1–3 × 0.5–1 cm; pedicels 1–3.5 cm long. Calyx green, persistent, winged; wings 1–
1.6 mm wide; lobes-5, ovate-narrowly lanceolate, 10–15 × 2–3.5 mm, distinctly nerved, fused 1/4th of its length,
slightly accrescent in fruits, acute-acuminate at apex. Corolla tube 0.4–0.7 cm long; lobes-5, blue, white at throat,
elliptic-obovate, 1–1.2 × 0.3–0.9 cm, obtuse-rounded at apex. Stamens-5; filaments short, yellow, fused to the
corolla, 1.5–3 mm long; anthers yellow, bottle shaped, straight, 3–6 mm long, opening by apical pores, later widen
to slits, papilla absent. Ovary green, ovate, 0.4–0.6 × 0.2–0.35 cm; style greenish white, 0.6–1 cm long, often longer
than the stamens, curved; stigma simple, rounded, faintly 2-lobed; lobes c. 0.1 cm long. Capsules brown, ovateelliptic, 1–1.5 × 0.6–0.95 cm. Seeds many, irregular or tetrahedral with shallowly sunken sides, 0.3–0.5 × 0.2–0.4
mm; testa reddish brown.
Chromosome number: 2n = 34 (Mallikarjuna et al., 1987).
Flowering & fruiting: September–April.
Habitat: In grasslands, at an elevation of 500–1200 m.
Distribution: It is vulnerable and endemic to South India. Klackenberg (1985) reported E.courtallense as a
local endemic, restricted to Tirunelveli hills. But it is much more common than the previous species and also
recorded from many districts in Kerala.
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Figure 2:.Exacum atropurpureum Bedd.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened;
E. Gynoecium; F. Stigma; G. Fruit; H. Seed (from Shahina P.M. & S anthosh Nampy 4993 ).
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Specimens examined: Kerala, Idukki district, Kulamav, 07.06.1984, N. Mohanan 82012 (MH); Vagamon,
17.08.2011, K.M. Manudev & P.M. Shahina 4992, Ibid., 17.08.2013, A.J. Robi & K.M. Manudev 135339 (CALI).
Pathanamthitta, district, Chuttippara hills, 15.05.1979, C.N. Mohanan 68363 (CAL, MH). Thiruvananthapuram
district, Agasthyamala, 24.04.1990, N. Mohanan & T. Shaju 02055 (TBGT), Ibid., 17.02.2011, K.M. Manudev, P.M.
Shahina & Santhosh Nampy 4913 (CALI); Athirumala, 12.10.1988, N. Mohanan 4215; Bonacaud, 18.05.1991, N.
Mohanan 10818, Ibid., 30.10.1992, E.S. Santhosh Kumar & M. Abdul Jabbar 14727 (TBGT), Ibid., s. die, N.
Mohanan 58823, Ibid., 01.10.1973, J. Joseph 44484 (MH), Ibid., 22.03.1978, M. Mohanan 54736 (CAL);
Chemungi, 05.02.1991, N. Mohanan 10325; Karamanayar, 30.07.1991, N. Mohanan 10704; Meenmutti, 06.11.1990,
N. Mohanan 10147; Thovazhu hill, s. die, K. Narayana Iyer 01445 (TBGT); Travancore, s. die, Bourdillion s.n.
(MH), Ibid., 08.1913, C.C. Calder & M.S. Ramaswami 858 (CAL). Wayanad district, Periya, Gurukula Botanical
Sanctury, 14.01.2013, P.M. Shahina & Santhosh Nampy 4976 (CALI). Tamil Nadu, Kanyakumari district, Way to
Muthukuzhivayal, 31.08.1976, A.N. Henry 48174 (CAL, MH). Theni district, High wavy mountain, 05.1917, Blatter
& Hallberg 496 (CAL).
Notes: E. courtallense is easily recognized by its delicate bottle shaped anthers, which is also found in E.
travancoricum, but the latter is separated by its short cushion like habit and succulent leaves.
Gamble (1923) described the variety laxiflorum based on Beddome‟s specimens from Travancore hills. There are
two sheets in MH and one sheet in Kew. Henry and Swaminathan (1983) selected one of the sheets in MH as the
lectotype (Acc. No. 33198). Unknowingly, Klackenberg (1985) selected the Kew specimen as the lectotype. Hence,
the lectotype designated by Henry and Swaminathan in 1984 will serve as the type of this variety.
4. Exacum klackenbergii Gopalan, J. Bombay Nat. Hist. Soc. 99(2): 271. 2002. Type: Tamil Nadu,
Tirunelveli district, Sangumuthirai, way to Pothigaimalai, Agasthyamalai, 05.02.1989, R. Gopalan 88726 (holo,
CAL!; iso, MH!).
Exacum wightianum var. uniflorum A.N. Henry & Swamin., J. Bombay Nat. Hist. Soc. 80: 459. 1983, syn. nov.
Type: Tamil Nadu, Tirunelveli district, Agastyamalai, 27.05.1963, A.N. Henry 16335 (holo, CAL!).
Figure 4
Herbs, 40–120 cm tall. Stems terete-4-lineolate, woody, much branched basally and apically. Petiole 0.4–1.2 cm
long; lamina elliptic-lanceolate, 3–8 × 1–15 mm, 3-nerved at base, acuminate at apex; attenuate at base. Cymes often
terminal, 1–3 flowered, or rarely solitary and axillary; bracts elliptic, 1–3 × 0.5–2.8 cm; pedicels 4-lineolate, 1–4 cm
long. Calyx green, persistent, dorsally winged; wings semi cordate at base, 1–1.5 mm wide, veins not prominent, not
accrescent in fruit; lobes-5, ovate-lanceolate, 8–15 × 3–5 mm, acuminate at apex. Corolla tube 6–9 mm long; lobes5, blue, yellow at throat, broadly elliptic, 1.5–3.5 × 0.7–2 cm, margins wavy, cuspidate. Stamens-5; filaments pale
green-yellow, 2–3 mm long; anthers yellow, linear, erect, oblong, 6–9 × 1–2 mm long, dehiscence through apical
pores that later widen to slits, papilla not distinct. Ovary green, oblong, 4–8 × 2–4 mm; style greenish white, 5–12
mm long, curved; stigma simple, rounded, faintly 2-lobed; lobes 1–1.3 mm long. Capsules brown, oblong-globose,
8–15 × 3–8 mm, unilocular. Seeds many, irregular, 0.3–0.5 × 0.1–0.3 mm; testa brown.
Chromosome number: Not reported.
Flowering & fruiting: February–August.
Habitat: Exposed wet grassy slopes in hill tops, about 1500 m. altitude.
Distribution: It is a local endemic, restricted to Tirunelveli hills, rare.
Specimens examined: Tamil Nadu, Tirunelveli district, Agastyamalai hills, 01.07.1964, Henry & Chandrabose
19181; Kalivayalpil, 01.06.1901, Barber 3023 (CAL, MH).
Notes: Exacum klackenbergii shows resemblance to E. wightianum but easily distinguished by its petiolate, ellipticlanceolate leaves, 4-lineolate-woody stem and larger flowers.
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Figure 3. Exacum courtallense Arn.: A. Habit; B. Plant in natural habitat; C. Flower; D. Calyx; E. Corolla opened;
F. Gynoecium; G. Anthers; H. Stigma; I. Apical pore of stamens; J. Fruit; K. Seeds (A from Manudev K.M. &
Shahina P.M. 4992; B-K from Shahina P.M. & Santhosh Nampy 4976).
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Figure 4. Exacum klackenbergii Gopalan: A. Flowering twig; B. Calyx; C. Dehisced anther; D. Flower; E. Stamen
(from N. Sasidharan s.n.).
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Henry and Swaminathan (1983) described E. wightianum var. uniflorum from Tirunelveli hills, differentiated from
the typical variety wightianum in having few, mostly solitary flowers. On critical study in consultation with the type
and protologue, it is found that it is conspecific to E. klackenbergii and is here reduced to the synonymy of the latter.
5. Exacum lawii C.B. Clarke in Hook.f., Fl. Brit. India 4: 98. 1883; Gamble, Fl. Madras 2: 874. 1923; Klack.,
Opera Bot. 84: 53. 1985; Manilal, Fl. Silent Valley 182. 1988. Type: Baba Budan hills, s. die, Law s.n. (lecto, K;
iso, K!).
Figure 5
Herbs, 3–30 cm tall. Stems pale green, 4-angular, minutely winged-4-lineolate, unbranched to sparsely branched;
branches confined to the upper part of the stem; internodes much longer than the leaves. Leaves sessile; lamina
ovate-orbicular, 0.3–1 × 0.7–1.3 cm, 3-nerved at base, acute-obtuse at apex, cuneate at base. Flowers solitary or few
in terminal or axillary lax cymes; bracts ovate, 0.3–0.5 × 0.2–0.4 cm; pedicels 0.5–5.5 cm long, slender, terminal
one often longer and slightly curved than the axillaries. Calyx green, persistent, wingless; lobes-4, elliptic-broadly
ovate, fused towards the very base, 1.8–3.5 × 2–3.5 mm, prominently nerved, accrescent in fruit; acute-acuminate at
apex. Corolla tube white, 0.4–1 mm long; lobes-4, blue-violet, broadly obovate, 0.3–1.2 × 0.3–0.7 cm, acute-obtuse
at apex. Stamens-5; filaments short, white, fused to the corolla, 1–2 mm long; anthers yellow, erect, rectangular,
opening by apical pores that later do not widen to slits, papilla absent, 0.5–1.5 mm long. Ovary green, ovate, 0.3–
0.6 × 0.2–0.35 cm; style bluish white, 2–3 mm long, straight as long as the stamens or a little beyond; stigma simple,
capitate, faintly 2-lobed; lobes c. 0.1 cm long. Capsule brown, globose, 0.4–0.8 × 0.4–0.6 cm. Seeds many, irregular
or tetrahedral with shallowly sunken sides, 0.2–0.5 × 0.2–0.3 mm; testa reddish brown.
Chromosome number: 2n = 56 (Mallikarjuna et al. 1987).
Flowering & fruiting: October–December.
Habitat: In higher elevation grasslands.
Distribution: India, fairly common in Maharashtra but rare in South India.
Uses: It is used as a laxative. Powdered plants are used against kidney disorders and plants boiled with oil used
for eye diseases (Struwe et al. 2002).
Specimens examined: Kerala, Idukki district, Anamalai, 10.10.1901, C.A. Barber 3729 (MH); Vagamon,
17.08.2013, A.J. Robi & K.M. Manudev 135338 (CALI); Vengoli peak, 30.09.1912, C.E.C. Fischer 3488 (CAL).
Kozhikode district, Vellarimala, 17.10.1997, A.K. Pradeep 56140, Ibid., 14.11.1997, A.K. Pradeep 56163 (CALI).
Palakkad district, Silent valley, Dam site, 04.12.1981, C. Satheesh Kumar 10207 (CALI). Wayanad district,
Chembra peak, 24.11.2012, P.M. Shahina & Santhosh Nampy 4958 (CALI). Tamil Nadu, Tirunelveli district,
Mahendrahill, s. die, s.coll. s.n. (MH).
Notes: E. lawii and E. sessile are difficult to distinguish easily. These are the only south Indian species having no
wings on calyx. But E. lawii can be separated by its long pedicellate flowers and prominently nerved calyx.
6. Exacum pedunculatum L., Sp. Pl. 112. 1753; Klack., Opera Bot. 84: 48. 1985. Type: The drawing in
Plukenet, Phytographia, Almagesti botanici mantissa. t. 343. f. 43. pl. 3. 1700 (holo!)
Exacum punctatum L.f., Suppl. Pl. 124. 1782. Type: India, 1777, Koenig s.n. (LINN!)
Exacum carinatum Roxb., Fl. Ind. 1: 415. 1820. Sabaea carinata (Roxb.) Spreng., Syst. Veg. 1: 426. 1825. Type:
Roxb. Icon No. 1210 (lecto!)
Exacum sulcatum Roxb., Fl. Ind. 1: 415. 1820. Sabaea sulcata (Roxb.) Spreng., Syst. Veg. 1: 426. 1825. Type:
India, s. die, Roxburgh s.n. (lecto, BM!).
Exacum pedunculare Arn., Ann. Sci. Nat. Bot. 11: 176. 1839; Wight, Icon. Pl. Ind. Orient. 2: 336. 1843. Type:
Wallich Cat. No. 4359 (holo!)
Figure 6
Herbs, 4–45 cm tall. Stems pale green, 4-angular, 4-lineolate, usually much branched. Leaves sessile-subsessile;
lamina oblong-elliptic, lanceolate, 3–7 × 0.7–2 cm, 3–nerved at base, acute at apex, attenuate at base. Cymes
terminal or axillary, often clustered, 1–5 flowered; bracts ovate-lanceolate, 0.5–2 × 0.3–0.6 cm; pedicels 0.5–3.5 cm
long. Calyx green, persistent, dorsally winged; wings semi cordate, 0.6–1.8 mm wide; lobes-4, hyaline towards the
edge, broadly ovate, 4–6.5 × 2–3.5 mm, fused 1/3rd of its length, not accrescent in fruits, acute or acuminate at apex.
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Figure 5. Exacum lawii C.B. Clarke: A. Plants in natural habitat; B. Flowering twigs; C. Flower; D. Calyx;
E. Corolla opened; F. Stamens; G. Gynoecium; H. Fruit; I. Seeds (A, D from Manudev K.M. 134732; B-C, E-I
Shahina P.M. & Santhosh Nampy 4958).
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Figure 6: Exacum pedunculatum L.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened; E. Apical pore of
stamens; F. Gynoecium; G. Stigma; H. Fruit; I. Seeds (from Shahina P.M. & Santhosh Nampy 134733).
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Corolla tube white, 0.4–1 mm long; lobes-4, blue, pale green-yellow at throat, elliptic-broadly ovate, 4–10 × 3–7
mm, cuspidate. Stamens-4; anthers yellow, erect, more or less bottle shaped, 2–3.5 mm long, opening by apical
pores that later do not widen to slits, papilla absent; filaments white, fused to the corolla, 0.5–1.2 mm long. Ovary
green, ovate-orbicular, 0.3–0.5 × 0.2–0.4 cm; style white, 5–7 mm long, deflexed; stigma simple, capitate, faintly 2lobed; lobes 0.1–0.3 mm long. Capsules brown, globose, 0.4–0.8 × 3–6 mm. Seeds many, round or tetrahedral with
shallowly sunken pits, 0.15–0.35 × 0.1–0.25 mm; testa reddish brown.
Chromosome number: 2n = 62 (Mallikarjuna et al., 1987).
Flowering & fruiting: January–December.
Habitat: This is one of the common species of Exacum in South India and occurs both in the eastern and
western Ghats. It is recorded from forests margins, open grasslands and banks in marshy fields.
Distribution: India, Sri Lanka and Bangladesh.
Specimens examined: Andhra Pradesh, Anantapur district, Anantapur, s. die, Tiruvenkatachari s.n. (FRC).
Chittoor district, Chittoor, 22.02.1918, s.coll. 426 (FRC); Kuppam, 30.04.1914, s.coll. 10310 (MH). Cuddapah
district, Bale Palle, 21.07.1962, J.L. Ellis 14318 (CAL). Krishna district, Bellamkonda, 1887, Gamble 18638 (CAL).
Kurnool district, Kurnool, 02.1953, C. Rajasekar Mudaliar 94406, 32619; Kristnachullypally, 06.1883, Gamble
10960 (DD); Nandyal, 1953, Rajasekar Mudaliar 94406 (MH). Nellore district, Nellore, 03.02.1929, K.C. Jacob
18527, Ibid., 03.1901, Ruiz 33249; Nepilogunta, 11.02.1916, s.coll. 12762; Tada, 13.03.1901, Sharmishta Gupta
33231 (MH), Ibid., 11.03.1962, D.C.S. Raju 201, Ibid., 26.02.1971, A.R.K. Sastry 770 (CAL). (MH). Visakapatanam
district, Visakapatanam, 03.12.2011, P.M. Shahina & Santhosh Nampy 134733 (CALI). Karnataka, Bellary
district, Siruguppa, 1952, Krishna Swamy 94241 (MH). Bengaluru district, Bengaluru, 02.1988, s.coll. 33246 (MH).
Chamarajanagar district, Sivasamudram, 12.05.1914, s.coll. 10402 (MH). Chickmagalur district, Chickmagalur,
1979, Kesava Murthy & Ramesh 6284 (CAL). Chitradurga district, Hosadurga-Holalkera road, 1979, Ramesh &
Sreenath s.n. (CAL). Dharwar district, Dharwar, 1978, Saldanha & Prakash 3426; Hugli, 02.1919, Sedgwick & Bell
5345 (CAL). Nallamalais, 26.11.1969, J.L. Ellis 32619 (MH), Ibid., 28.11.2013, S. Syam Radh, P.G. Arun Kumar &
P.M. Shahina 134739 (CALI). Mysore district, Bandipur, 1965, B.D. Naithani 23191; Mysore, 27.01.1965, B.D.
Naithani 23191, Ibid., 11.1987, s.coll. 33230 (MH). Tamil Nadu, Chennai district, Chennai, s.coll. 33242; M.C.C.
Campus, 07.11.1985, D. Narasimhan 936 (MH). Chengalpatt district, Kambakkam hills, 02.1914, s.coll. 10243
(MH). Coimbatore district, Coimbatore, 24.02.1924, K.C. Jacob 17376, Ibid., 28.01.1932, M. Rathnavel 201;
Siruvani, 25.08.1960, A.N. Henry 646; Sivasamudram, 24.02.1924, K.C. Jacob 17376 (CAL, MH). Kancheepuram
district, Vandalur, 06.02.1915, s.coll. 11450 (MH). Nagapattinam district, Caleroon river, 11.11.1976, K.M.
Matthew 6139, Ibid., 19.02.1977, K.M. Matthew 6719, Ibid., 21.02.1978, Rajendran & Diravium 12150, Ibid.,
24.02.1978, Rajendran & Diraviam 12234; Kollidam, 15.11.1969, K.M. Matthew 10575, Ibid., 29.12.1969, K.M.
Matthew 10734, Ibid., K.M. Matthew 14723, Ibid., 30.07.1970, K.M. Matthew 11990 (RHT). Namakkal district,
Namakkal, 10.12.1978, K.M. Matthew 19963 (MH). Salem district, Attur, 20.02.1979, T.S. Jayaseelan 26520;
Salem, 05.01.1978, V. Alphonse 10793, Ibid., 27.06.1978, N. Venugopal 14409 (RHT), Ibid., 10.2000, K.C. Jacob
18042 (MH). South Arcot district, South Arcot, 07.04.1978, K.M. Matthew 12872, Ibid., 30.01.1980, K.M. Matthew
26196 (RHT); Perugudinedu, 02.1898, s.coll 33254 (MH); Takarai R.F. 04.02.1931, V. Narayanaswamy 5064, Ibid.,
19.01.1978. K. Ramamurthy 52844 (RHT, CAL). Thanjavur district, Thamarankottai, 07.03.1989, S. Regupathy
1028; Thanjavur, s. die, s.coll. 33247 (MH). Tiruchirappalli district, Erattamalai, 23.03.1984, K.M. Matthew 29901;
Kondayampettai, 06.02.1969, K.M. Matthew 9972; Lalgudi, 17.02.1978, Perianayagam 11966; Oosipalayam,
28.12.1976, K.M. Matthew 5672, Ibid., 23.01.1998, K.M. Matthew 9779; Peramangalam, 15.01.1982, K.M.
Matthew, John Britto & N. Rani 28995; Srirangam island, 19.01.1979, S. Perianayagam 21133, Ibid., 02.04.1979,
C. Manoharan 22633, Ibid., 23.01.1980, K.M. Matthew 25992, Ibid., 26.01.1980, S. Perianayagam & R. Natarajan
26153, Ibid., 07.03.1992, C.D.K. Cook 30758; Tiruchirappalli, 17.03.1969, K.M. Matthew 10089, Ibid., 26.02.1976,
C. Rajamani 1278; Ibid., 30.07.1990, K.M. Matthew 11990; Thuraiyur, 20.03.1978, K.M. Matthew 12549 (CAL,
RHT), Ibid., 20.03.1978, K.M. Matthew 12552, Ibid., 24.07.1978, K.M. Matthew & N. Venugopal 15529, Ibid.,
27.11.1978, K.M. Matthew & V.S. Manickam 19340, Ibid., 06.01.1979, A. Diraviam & Xavier 20712 (RHT).
Tirunelveli district, s.loc., 04.09.1963, A.N. Henry 17449 (MH). Villupuram district, Kalpadai, 21.12.1926, S.R.
Raju & Nagathan 17843 (MH). Telangana, Karim Nagar district, Recha palli, 22.12.1964, G.V. Subba Rao 21897,
Ibid., 28.02.1959, K. Subramanyam 7811 (MH). Medak district, Medak, 1959, Sebastian 8004 (CAL, MH).
Notes: Exacum pedunculatum is a beautiful plant, usually with terminal/axillary, profuse cymes. It is often confused
with E. petiolare but differs by its subsessile-sessile, oblong-elliptic or lanceolate leaves, basally fused stamen
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filaments and fruits without enlarging calyx. This is one among the four species of Exacum in South India having
strict poricidal dehiscence, in which the pores do not widen in to slits.
Linnaeus (1753) cited Plukenet‟s (1700) drawing in Mantissa for E. pedunculatum and hence it is the holotype of the
species.
7. Exacum petiolare Griseb. in A. DC., Prodr. 9: 46. 1845; Klack., Opera Bot. 84: 54. 1985. Exacum
pedunculatum var. petiolare (Griseb.) Trimen, Handb. Fl. Ceylon 3: 182. 1895. Type: Asia, s. die, Hugel s.n. (lecto,
W!).
Figure 7
Herbs, 10–50 cm tall. Stems 4-angular, winged, sparsely-much branched. Petiole 2.5–5 cm long; lamina broadly
ovate, 2.5–7 × 0.7–3.5 cm, 3–5 nerved at base, acute at apex, attenuate at base. Cymes terminal or axillary, 1–5
flowered; bracts ovate, 1–3 × 0.8–1.5 cm; pedicels 0.5–2.5 cm long. Calyx green, hyaline towards the edge,
persistent, prominently winged; wings cordate, prominently nerved, 1.8–3 mm wide; lobes-4, ovate, 3–5.5 × 2–3.5
mm, fused 1/3rd of its length, accrescent in fruits with prominent veins, acuminate at apex. Corolla tube pale green,
0.8–1.5 mm long; lobes-4, pale blue or white, pale green at throat, elliptic-broadly ovate, 6–10 × 2.3–7 mm, acute at
apex. Stamens-4; filaments pale green, fused to the corolla, 0.6–1.2 mm long; anthers yellow, erect, linear-ovate,
1.8–2.5 mm long, opening by apical pores, later widen into slits, papilla absent. Ovary green, ovate-orbicular, 1.5–
2.5 × 1–3 mm; style white, 4.5–7 mm long, deflexed; stigma simple, capitate, faintly 2-lobed; lobes 0.25–0.4 mm
long. Capsules brown, globose, 6–10 × 3–6 mm. Seeds many, tetrahedral with shallowly sunken pits, 0.15–0.35 ×
0.1–0.25 mm; testa reddish brown.
Chromosome number: 2n = 62 (Mallikarjuna et al. 1987).
Flowering & fruiting: July–December.
Habitat: Road side cuttings and moist places in grass or on damp rocks, usually in shade.
Distribution: India and Sri Lanka. It is fairly common in South India, distributed both in the eastern and
western Ghats.
Specimens examined: Andhra Pradesh, Visakapatanam district, near Sileru approach, 24.10.1972, G.V. Subba
Rao 42713 (MH). Kurnool district, way to Diguvatta, 24.10.1964, J.L. Ellis 22193; s.loc., 12.1880, J.S. Gamble
8847 (MH). Karnataka, Bengaluru district, on the way to Ramanagaram, 23.02.1978, S.R. Ramesh 263 (JCB).
Chickmagalur district, Charmadi ghat, 13.11.1978, C.J. Saldanha & P. Prakash s.n. (CAL, JCB). Mysore district,
Chianthapura, 10.1908, A. Meebold 9809 (CAL). Dakshina Kannada district, Dakshina Kannada, 10.11.1962, R.K.
Arora 1128 (CAL). Shimoga district, Hosur-Sagar road, 26.09.1978, K.P. Sreenath & K.R. Keshava Murthy 2909;
Hulical ghat, 10.10.1962, R.S. Raghavan 83129 (CAL, JCB); Mattiga, near Yedur, 06.10.1962, R.S. Raghavan
83010, Ibid.,16.10.1964, R.S. Raghavan 90465 (CAL); Kudajadri, 08.11.2013, P.M. Shahina, A.P. Janeesha & H.S.
Ashwini 134717 (CALI). Uttara Kannada district, Dandeli, 29.09.1978, K.P. Sreenath & K.P. Keshava Murthy 3066;
Uttara Kannada, 09.1887, W.A. Talbot 155 (CAL). Kerala, Idukki district, Anamalais, 1838, Beddome 38;
Thekkady, 29.08.1912, C.E.C. Fischer 3479 (CAL). Palakkad district, Mukkali, 15.10.1979, N.C. Nair 64665 (CAL,
MH); Parambikulam, 11.1909, A. Meebold 12380 (CAL), Ibid., 24.09.2013, A.P. Janeesha & P.M. Shahina 4999
(CALI); Walayar Dam, 25.10.1963, J. Joseph 17869 (MH). Kannur district, Paithalmala, 27.09.2012, P.M. Shahina,
A. Anna Ancy Antony & Santhosh Nampy 4929, 4934 (CALI). Tamil Nadu, Coimbatore district, Mount Stouert,
27.10.1961, J. Joseph 13342 (CAL). Nilgiris district, Nilgiris, 11.1884, J.S. Gamble 15438 (CAL).
Notes: E. petiolare and E. klackenbergii are the only two south Indian species having distinct petioles on leaves.
The former is distinct from the latter in having tetramerous flowers and prominently winged calyx which is
prominently nerved and accrescent in fruits. E. petiolare is also easily differentiated from E. sessile, E. lawii and E.
pumilum by its prominently winged, accrescent calyx and petiolate leaves.
8. Exacum pumilum Griseb. in A. DC., Prodr. 9: 46. 1845; Klack., Opera Bot. 84: 50. 1985. Type: Bombay,
Salsetta, s. die, Graham s.n. (lecto, W!).
Figure 8
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Figure 7. Exacum petiolare Griseb.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened; E. Apical pores of
stamen; F. Gynoecium; G. Stigma; H. Fruit; I. Seeds (from Shahina P.M., Anna Ancy Antony A. & Santhosh
Nampy 4929).
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Slender herbs, 5–40 cm tall. Stems green, 4-angular, 4-lineolate, branched. Leaves sessile; lamina broadly oblonglinear lanceolate, 0.3–7 × 0.2–3 cm, 1 or 3–nerved at base, obtuse at apex; cuneate at base. Cymes lax, terminal or
axillary, 1–5 flowered; bracts linear lanceolate, 0.5–1.5 × 0.2–0.5 cm; pedicels 1–3.5 cm long. Calyx green, hyaline
towards the edge, persistent, winged; wings cordate, 1.8–3 mm wide; lobes-4, ovate, subulate, 4–6.5 × 1–2.5 mm,
fused 1/3rd of its length, without prominent veins, not accrescent in fruits, acute-acuminate at apex. Corolla tube
white, 0.4–1 mm long; lobes-4, blue-violet, broadly ovate, cuspidate, 6–9.5 × 3–6 mm. Stamens-4; filaments bluish
white, fused to the corolla, 0.8–1.6 mm long; anthers yellow, erect, rectangular, 1–2.5 mm long, opening by apical
pores that later do not widen to slits, papilla absent. Ovary green, oblong, 4–5.5 × 3–4 mm; style white, as long as
the stamens or longer, 3.5–6 mm long, deflexed; stigma simple, capitate, faintly 2-lobed; lobes 0.25–0.4 mm long.
Capsules brown, globose, 3–7 × 2–4 mm. Seeds many, tetrahedral with shallowly sunken pits, 0.15–0.25 × 0.1–0.25
mm; testa reddish brown.
Chromosome number: n = 31 (Mallikarjuna et al. 1987).
Flowering & fruiting: September–December.
Habitat: On grassy slopes, banks of streams and also on wet rocks.
Distribution: India, in the eastern and western Ghats.
Specimens examined: Karnataka, Chitradurga district, Lokadolalu Hosadurg, 21.09.1979, B.R. Ramesh & K.P.
Sreenath 7249 (CAL). Hassan district, Devalkarai, 13.09.1970, S. Suresh 35 (JCB). Shimoga district, Eduvanji
sagar-jogroad, 27.09.1978, K.R. Kesava Murthy & K.P. Sreenath 2958 (CAL). Kerala, Palakkad district, Anamooly,
25.09.1997, R. Ansari 51484 (CAL); Below Ayyapankoil area, 26.10.1976, E. Vajravelu 48704; Mampara,
05.10.2013, K.M. Prabhu Kumar 4986; Nelliyampathy, 03.11.2011, P.M. Shahina & Santhosh Nampy 134731
(CALI); s.loc., s. die, Stocks law s.n. (CAL, MH).
Notes: Exacum pumilum is related to E. pedunculatum, E. sessile and E. lawii in having the stamen filaments basally
fused and the anthers opening by apical pores that later do not widen to slits to the base. From E. pedunculatum,
differs by its more slender habit and smaller, rectangular anthers and from E. sessile and E. lawii, by its oblonglinear lanceolate leaves and winged or keeled calyx.
9. Exacum sessile L., Sp. Pl. 1: 112. 1753; Klack., Opera Bot. 84: 50. 1985; Manilal, Fl. Silent Valley 182.
1988. Type: Centaurium zeylanicum minus, flore luteo, Herb. Hermann Vol. 3. p. 42. (lecto, BM!).
Exacum dichotomum Wall., Num. List 152. 1831. nom. nud. Type: Wallich Cat. No. 4359 F (!).
Exacum macrantherum Miq., Anal. Bot. Ind. 3: 10. 1852. Type: Metz 582 (lecto, U!).
Figure 9
Herbs, 5–45 cm tall. Stems 4-angular, winged (wings 1–3 mm broad). Leaves sessile; lamina ovate-orbicular, 0.5–
1.5 × 0.7–1.3 cm, 3–nerved at base, acute-obtuse at apex, cordate at base. Flowers often terminal solitary or axillary,
lax cymes, sessile-pedicellate; bracts ovate, 0.3–0.8 × 0.3–0.5 cm; pedicels short, 0.5–1.5 cm long, drooping. Calyx
green, persistent, wingless; lobes-4, elliptic-broadly ovate, fused to the very base, 3–4.5 × 2–3.5 mm, prominently
nerved, not accrescent in fruit, acute at apex. Corolla tube white, 0.6–1.5 mm long; lobes-4, blue-violet, broadly
obovate, 0.3–1 × 0.2–0.7 cm, acute-obtuse at apex. Stamens-4; filaments short, white, fused to the corolla, 0.3–0.6 m
long; anthers yellow, erect, rectangular, 0.5–1.2 mm long, opening by apical pores that later do not widen to slits,
papilla absent. Ovary green, ovate-obovate, 0.5–2.5 × 3–4.5 mm; style bluish white, as long as or slightly longer
than the stamens, 2–4 mm long, straight; stigma simple, capitate, faintly 2-lobed; lobes c. 0.1 cm long. Capsules
brown, globose, 4–8 × 4–6 mm. Seeds many, irregular or tetrahedral with shallowly sunken sides, 0. 1–0.25 × 0.2–
0.3 mm; testa reddish brown.
Chromosome number: n = 31 (Mallikarjuna et al. 1987).
Flowering & fruiting: October–December.
Habitat: On wet rocks, in wet open grasslands and moist places.
Distribution: India and Sri Lanka, fairly common in South India.
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Figure 8. Exacum pumilum Griseb.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened; E. Apical pore of
stamen; F. Gynoecium; G. Stigma; H. Fruit; I. Seeds (A-B from Shahina P.M. & Santhosh Nampy 134731; C-I
from Prabhu Kumar K.M. 4986).
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Figure 9. Exacum sessile L.: A. Flowering twigs; B. & C. Flower; D. Calyx; E. Gynoecium; F. Corolla opened; G.
Stamens; H. Stigma; I. Fruit; J. Seeds (from Shahina P.M. & Santhosh Nampy 3302).
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Specimens examined: Karnataka, Chickmagalur district, Baba Budan hills, 07.11.2013, P.M. Shahina, A.P.
Janeesha & H.S. Ashwini 134716 (CALI). Hassan district, Bannuhalla, 10.10.1969, C.J. Saldanha 15289; Bisle
ghat, 18.08.1969, C.J. Saldanha 15098; Devarunde, 16.09.1969, C.J. Saldanha 177935; Devanangaundi,
13.09.1970, N. Sathyananda 12; Shiradi ghat, Panorama point, 03.09.1969, C.J. Saldanha 15159 (JCB). Kerala,
Ernakulam district, Malayattoor, 18.08.1913, M. Rama Rao 476; Kavalay, 11.1909, A. Meebold 12334; Killan hills,
01.09.1913, M. Rama Rao 1553 (CAL). Idukki district, Dhanas valley, 17.10.1989, P. Bhargavan 90996; Kulamav,
20.08.1977, K. Vivekananthan 50433, Ibid., 08.10.1982, C.N. Mohanan 74521 (MH), Ibid., 12.10.1982, C.N.
Mohanan 74589, Ibid., 03.10.1983, C.N. Mohanan 79965, Ibid., 26.09.1981, C.N. Mohanan & B. Ramanjujan
72001 (CALI); Kurisumala, 23.08.1975, J. Joseph 46506; Painavu-kulamvu, 21.08.1986, K. Vivekananthan & V.S.
Raju 71740 (MH); Thenkanchi, 23.09.1972, B.D. Sharma 40855; Vagamon, 17.08.2013, A.J Robi. & K.M. Manudev
135338 (CALI). Kannur district, Paithal mala, 27.09.2012, P.M. Shahina & Santhosh Nampy 4933 (CALI). Kollam
district, Chittar, 31.07.1978, C.N. Mohanan 58351 (CAL, MH); Chuttipara hills, 15.05.1980, C.N. Mohanan 68370
(MH). Kottayam district, Kuttikanum-Perumade, 25.09.1964, K. Vivekanathan 21372 (MH). Kozhikode district,
Kaatulla mala, 29.07.2010, P.M. Shahina & Santhosh Nampy 3302; Kakkayam, 19.09.2013, A.P. Janeesha & S.
Syam Radh 134702; Thampuran kolli, 30.10.2013, P.M. Shahina & Santhosh Nampy 4989 (CALI). Palakkad
district, Aruvanpara forest, 08.10.1979, N.C. Nair 64415 (MH, CAL), Ibid., 05.12.1982, T. Sabu 11047 (CALI).
Thrissur district, Athirapally, 13.09.1976, K. Ramamurthy 48497 (CAL, MH); Mudiyankunnu, 13.12.2013, A.P.
Janeesha & S. Syam Radh 5000 (CALI); Thrissur, 08.1884, J.S. Gamble 14718 (CAL). Thiruvananthapuram
district, Bonacaud, 24.11.1984, s.coll. s.n. (CALI), Ibid., 09.10.1973, J. Joseph 44648; Meenmutty, 02.10.1983,
C.N. Mohanan 79919; Ponmudi, 13.09.1977, N.C. Nair 51402 (MH), Ibid., 16.10.1959, K.M. Matthew 1334, Ibid.,
20.09.1968, K.M. Matthew 9259, Ibid., 11.09.1970, K.M. Matthew 12345, Ibid., 12.09.1970, K.M. Matthew 12383,
Ibid., 15.09.1985, K.M. Matthew 18581 (RHT), Ibid., 16.08.1980, M. Mohanan 69215 (MH), Ibid., 16.08.1980, M.
Mohanan 69215 (CALI), Ibid., 28.11.2012, P.M. Shahina & Santhosh Nampy 4965 (CALI). Vallakadavu,
04.10.1976, K. Vivekananthan 48594 (CAL, MH); s.loc., 1873, Beddome s.n. (MH). Wayanad district, Churam,
07.10.2012, K.M. Manudev & P.M. Shahina 4935 (CALI); Manikkunnu, 18.11.2012, P.M. Shahina & Sheba M.
Joseph 4953 (CALI). Tamil Nadu, Coimbatore district, Pandavarimalai, Cinamalai hills, 04.11.1914, C.E.C.
Fischer 11434 (MH). Dindigul district, Palamalai, 12.01.1987, K.M. Matthew 48321; Dindigul, 30.12.1987, K.M.
Matthew 52368 (RHT). Kanyakumari district, 11.09.1969, B.V. Shetty 32347; Kodayar, 07.08.1977, A.N. Henry
49649 (CAL, MH); Kuliratti, 26.01.1984, N. Parthasarathy 668; Mahendragiri, 11.09.1969, B.V. Shetty 32347;
Muthukuzhivayal, 09.09.1976, A.N. Henry 48310; Paralai, Anamalai, 07.11.1901, C.A. Barber 3981 (MH). Nilgiris
district, Nilgiris, 18.11.1886, s.coll. 18417 (MH). Salem district, Namakkal, 12.01.1986, K.M. Matthew & John
Britto 28916 (RHT). Telangana, Medak district, Medak, 28.01.1992, B.R.P. Rao & C. Prabhakar 11419 (SKU).
Nisamabad district, Gundaram R.F., 11.02.1990, B.R.P. Rao & K. Hanumanthappa 9680; Manchippa, 05.04.1989,
K. Hanumanthappa 554, Ibid., 05.04.1989, Ravi Prasad Rao & K. Hanumanthappa 9039; Naparam, 10.03.1990,
B.R.P. Rao 9709 (SKU).
Notes: Exacum sessile closely resembles to E. lawii. Both are small herbs with ovate-cordate leaves and without
calyx wings. From E. lawii, it is easily separated by its sessile-shortly pedicellate, drooping flowers at the junction
of branching stem where as in E. lawii, the flowers are always long pedicellate (2–4.5 cm long).
10. Exacum tetragonum Roxb., Fl. Ind. 1: 413. 1820; Klack., Opera Bot. 84: 37. 1985. Type: Herb.
Roxburgh, Wallich 4356 A (lecto, K-W!).
Exacum bicolor Roxb., Fl. Ind. 1: 413. 1820. Exacum tetragonum var. bicolor (Roxb.) Hook.f., Bot. Mag. 73: t.
4340. 1847. Type: Cuttack, Roxburgh (n.v.).
Exacum grandiflorum Wall. ex G. Don, Gen. Hist. 4: 212. 1838. nom. illeg. Type: Courtallum, Wallich 4358 (lecto,
K-W!).
Exacum stylosum Wall. ex G. Don, Gen. Hist. 4: 212. 1838. E. tetragonum Roxb. var. stylosa (Wall. ex G. Don)
C.B. Clarke in Hook.f., Fl. Brit. India 4: 95. 1883. Type: Prome, 1826, Wallich 4355 (lecto, K-W!).
Exacum perrottetii Griseb. in A. DC., Prodr. 9: 45. 1845. 1923. Type: 1840, Perrottet s.n. (holo, G-DC!).
Exacum bellum Lindl. ex Hance, London J. Bot. 7: 472. 1848. Type: Victoria peak, Hongkong, Hance 505 (lecto,
BM!).
Exacum horsfieldianum Miq., Fl. Ned. Ind. 2: 556. 1857. Type: Java, Priangan, Horsfield s.n. (lecto, BM!).
Exacum metzianum Hohen. ex C.B. Clarke in Hook.f., Fl. Brit. India 4: 96. 1883. Type: India, Mangalore,
Hohenacker 857 (holo, HAL!).
Exacum sulcatum Wight ex C.B. Clarke in Hook.f., Fl. Brit. India 4: 96. 1883. Type: Wight 96 (K!).
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Exacum cambodianum Dop, Bull. Soc. Bot. France 59: 145. 1912. Type: Cambodge, Mont de Pursat, Godefroy 445
(lecto, P).
Figure 10
Herbs, 15–120 cm tall. Stems 4-anglular, winged (wings 0.2–0.4 cm broad), branched basally and apically. Leaves
sessile-subsessile; lamina broadly elliptic-ovate, spathulate or linear lanceolate-broadly oblong, 4–16 × 1.5–2.5 cm,
3–5 nerved at base, acute at apex, cuneate at base. Cymes dichasial, terminal or axillary, lax-dense, 1–5 flowered;
pedicels 0.5–3 cm long. Calyx green, persistent, dorsally winged; wings 3–5 mm wide; lobes-4, ovate-lanceolate, 1–
1.5 × 0.3–0.5 cm, acute-acuminate at apex. Corolla tube yellowish white, 0.5–1 cm long; lobes-4, violet at the apex
and white the rest, yellow at throat, obovate-elliptic, 3–5 × 1–2 cm, cuspidate. Stamens-4; filaments pale greenyellow, short, 0.3–1.5 cm long; anthers orange yellow, linear, curved, sagittate, 1–1.8 cm long, dehiscence through
apical pores, later widen to slits. Ovary green, ovate, 0.5–1.5 × 0.3–0.8 cm; style greenish white, 1–2 cm long,
deflexed; stigma simple, rounded, faintly 2-lobed; lobes c. 0.15 cm long. Capsule brown, oblong-ovate, 1–2 × 0.8–1
cm, unilocular. Seeds many, tetrahedral, 0.2–0.35 × 0.1–0.2 mm; testa reddish brown.
Chromosome number: 2n = 62 (Mallikarjuna et al. 1987).
Flowering & fruiting: January–December.
Habitat: It occurs in exposed grasslands and occasionally at road cuttings.
Distribution: E. tetragonum is distributed in India, Philippines, New Guinea and northern Australia
(Klackenberg, 1985). It is the most widespread species of this genus in India, distributed from sea level to about
2000 m altitude.
Local name: Kannanthali (Malayalam).
Uses: Uses as a substitute for other gentians and an antidiabetic, stomachache and antifungal agent (Kirtikar &
Basu, 1935; Sreelatha et al. 2007).
Specimens examined: Andhra Pradesh, East Godavari district, Sukumarai hill, J.S. Gamble 16871 (CAL).
Karnataka, Chickmagalur district, Baba Budan hills, 10.1908, A. Meebold 19599, Ibid., 22.10.1965, R.K. Arora
5210 (CAL). Dakshina Kannada district, Uppinangadi, 12.11.1960, R.K. Arora 3448; Kaskal, 07.11.1960, R.K.
Arora 3356 (CAL). Shimoga district, Kudajadri, 08.11.2013, P.M. Shahina, A.P Janeesha. & H.S. Ashwini 134718
(CALI). Uttara Kannada district, Uttara Kannada, 1880, W.A. Talbot s.n. (DD). Kerala, Idukki district, Anamalai
hills, 30.12.1911, C.E.C. Fischer 3235 (CAL); Chinnar, Marayur, Ibid., 24.02.1903, Roshni Balakrishnan 89915, K.
Reesha 89430, Smitha 89130, Ibid., 25.02.1903, N. Shylaja 88329, Ibid., 25.02.1903, K. Nishitha 90430, Ibid.,
24.02.1903, M.B. Reena 89014, N. Divya 90515, Ibid., 24.02.2003, K.V. Radhika 88615, A.M. Dhanya 89615
(CALI); Idukki-kattapana, 08.11.1981, B. Ramanjujan 72417; Kulamavu, 11.10.1982, C.N. Mohanan 74549, Ibid.,
07.06.1984, C.N. Mohanan 82013; Kurisumala, 08.11.1984, Fr. Kadavil 928; Meenmutty, 04.10.1983, C.N.
Mohanan 79974 (CAL, MH); Munnar, 13.12.1970, M.K. Sreedharan Nambiar 222 (CALI); Painavu, 08.11.1981,
C.N. Mohanan 71212, V.S. Raju 71213; Rajamalai, 26.12.1983, A.G. Pandurangan 66500; Vallakadavu, 3.09.1972,
B.D. Sharma 40841 (CAL, MH). Kannur district, Chandanathode, 08.11.1978, V.S. Ramachandran 58615 (CAL,
MH); Kannur, 31.10.1965, J.L. Ellis 25783 (MH); s.loc., s. die, N.L. Bor s.n. (DD). Kasaragod district, Bela,
01.10.1982, R. Ansari 74421 (MH). Kollam district, Pamba dam-Anathode, 15.12.1974, K. Vivekananthan 45283
(CALI), Ibid., 09.11.1975, K. Vivekananthan 46579 (CAL, CALI). Kozhikode district, Chelannur, 23.09.2010, P.M.
Shahina, Johny & Santhosh Nampy 3431; Kurichiar mala, 28.10.2013, A.P. Janeesha & P.M. Shahina 4988 (CALI).
Malappuram district, Calicut University Campus, 05.07.1976, Majeed 20693, Ibid., 04.02.1977, E. Saradamma s.n.,
Ibid., 10.12.1981, A. Rajani 156, Ibid., 28.03.1982, Egy T. Paul 200, Ibid., 30.11.1982, Shanthi K. Nair 2010; Ibid.,
11.09.1984, Raja Lakshmi K. 2285, Ibid., 10.10.1984, Mary Princy 1886, Ibid., 30.10.1985, P.A. Naseem 5443,
M.P. Anitha 5141, Ibid., 05.10.1986, Jaison Lal 4398, Ibid., 12.08.1987, Kutty Sankaran 103, Ibid., 08.03.1990,
Betsy K. Mathai 1782, Kadalundi, 26.08.1998, Ravindra Kurup 24630 (CALI). Palakkad district, Poochipara,
10.12.1980, N.C. Nair & P. Bhargavan 69501 (CAL); Silent valley, 24.09.1977, R. Ansari 51462, Ibid., 04.10.1979,
N.C. Nair 64441, Ibid., 09.10.1979, N.C. Nair 64250 (CAL), Ibid., 04.12.1981, T. Sabu 10005; KunthipuzhaPoochipara, 10.12.1980, M.C. Nair 69501; Way to Valiyaparathode, 20.01.1980, P. Bhargavan 65607 (CALI).
Pathanamthitta district, Kakki, Coodrical Foreset, 25.12.1988, N. Anilkumar 1330 (CAL, CALI). Kottayam district,
Pamba, 24.06.1968, D.B. Deb 30305 (MH). Thrissur district, Peruvan mala, 06.11.2010, P.M. Shahina, Alfred Joe &
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Figure 10. Exacum tetragonum Roxb.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened; E. Stamens;
F. Gynoecium; G. Fruit; H. Stigma; I. Seeds (from Alfred Joe & Shahina P.M. 3961).
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Sandhya 3961; Ibid., 03.10.2011, P.M. Shahina & Santhosh Nampy 4901; Vilangan kunnu, 02.10.2010, P.M.
Shahina & Santhosh Nampy 3061 (CALI). Wayanad district, Chembra, 24.11.2012, P.M. Shahina, A.P. Janeesha &
Satheesh 4959; Manikkunnu, 18.11.2012, P.M. Shahina & Sheba M. Joseph 4954; Wayanad, 22.11.1909, C.A.
Barber 8507 (CALI). Tamil Nadu, Coimbatore district, Siruvani, 18.12.1956, K. Subramanyam 10478 (CAL).
Nilgiris district, Benne forest, 19.07.1960, K. Subramanyam 1796; Brahmagiris, 06.12.1907, C.E.C. Fischer 225;
Gudalur, 09.01.1903, s.coll. 5561, Ibid., 18.11.1958, K.M. Sebastine 7397; Naduvattam, 10.1886, J.S. Gamble
18315; Nilgiris, 1880, W.A. Talbot s.n. (DD), Ibid., 1887, M.A. Lawson s.n., Ibid., 10.1884, J.S. Gamble 14873
(CAL).
Notes: The south Indian populations are usually known under the name E. bicolor. Klackenberg (1985) in his
monograph on Exacum, considered E. bicolor and E. tetragonum as conspecific (both published at the same time)
and chose the latter epithet for this species, being the best known and widely used name.
Exacum tetragonum is the only species with bi-coloured petals (blue to violet or white at the base with violet tips),
but single coloured populations also met with. The petals also change their color with age. In South India, the plants
are tall and flowers are large with long, curved anthers and broader calyx lobes which tapering abruptly to a long
point at the apex.
Klackenberg (1985) considered E. tetragonum as the most widely distributed and variable species in this genus. E.
tetragonum closely resembles to E. tetragonum var. grande but differs by its non-amplexicaul leaves, usually curved
anthers and 2-coloured petals. Roxburgh (1832) stated that “this is one of the most elegant plant, the flowers not
only numerous, large and beautiful but retaining their beauty and expansion for many days, which is a rare
circumstance in an Indian plant”.
11. Exacum tetragonum var. grande (Klack.) Shahina & Nampy, stat. nov. E. grande Klack., Oper. Bot. 84:
43. 1985. Type: India, Karnataka, Chickmagalur district, Baba budan hills, along road from Chickmagalur Dattatrepyapeeta, 09.10.1982, Klackenberg & Lundin 321 (holo, S!).
Exacum perrottetii sensu auct. Wight, Icon. Pl. Ind. Orient. 4: 7. t. 1322. 1850, C.B. Clarke in Hook.f., Fl. Brit. India
4: 95. 1883, Gamble, Fl. Madras 872. 1935, non Griseb. 1845.
Figure 11
Herbs, 15–50 cm tall. Stems 4-angular, winged (wings c. 0.2 cm broad), branched apically. Leaves sessile; lamina
elliptic-ovate, 5–12 × 1.5–6 cm, 3–5 nerved at base, acute at apex, amplexicaul at base. Flowers terminal or axillary,
few-many, lax-dense dichasial cymes; bracts ovate, 3–6 × 1–2 cm; pedicels 1–5 cm long. Calyx green, persistent,
dorsally winged; wings 1–1.5 mm wide, not distinctly nerved, fused 1/5 th of its length, not accrescent in fruit; lobes4, ovate-lanceolate, 7–15 × 2–3.5 mm, acute-acuminate at apex. Corolla tube white, 0.5–0.8 cm long; lobes-4, violet,
yellow at throat, obovate-elliptic, 2–4 × 0.5–1 cm, cuspidate. Stamens-4; filaments short, pale green-yellow, 1.5–3
mm long; anthers orange yellow, linear, straight-bent, sagittate, 5–8 mm long, dehiscence through apical pores that
later widen to slits, papilla absent. Ovary green, ovate, 0.25–0.5 × 0.2–0.3 cm; style greenish white, longer than the
stamens, 0.4–0.8 cm long, deflexed; stigma simple, rounded, faintly 2-lobed; lobes c. 0.1 cm long. Capsules brown,
elliptic-ovate, 1–2 × 0.4–0.8 cm, unilocular. Seeds many, irregular or tetrahedral with shallowly sunken sides, 0.25–
0.4 × 0.1–0.2 mm; testa brown.
Chromosome number: Not reported.
Flowering & fruiting: August–November.
Habitat: In open grasslands and in road side earth cuttings.
Distribution: It is a rare species endemic to peninsular India, Klackenberg (1985) cited a specimen from
Mahendragiri, Ganjam district in Orissa. Mahendragiri might be „Mahyandra hills‟ in Kanyakumari district and
hence the occurrence of this species in Orissa is doubtful.
Specimens examined: Andhra Pradesh, East Godavari district, Sukumari Hill, s. die, Gamble 16071 (CAL).
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Figure 11. Exacum tetragonum var. grande (Klack.) Shahina & Nampy: A. Habit & Habitat; B. Flower;
C. Inflorescence (from Prabhu Kumar K.M. 7577).
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Karnataka, Chickmagalur district, Baba Budan hills, C.J. Saldanha s.n. (JCB). Kerala, Palakkad district, Dhoni
hills, 26.09.2013, K.M. Prabhu Kumar 7577 (CMPR). Wayanad district, Mananthavady, 08.1885, s.coll. s.n. (MH);
Periya, 26.11.2013, P.M. Shahina & Santhosh Nampy 4901 (CALI). Tamil Nadu, Coimbatore district, Dimbam,
1905, Fischer 630 (CAL). Nilgiris district, Coonoor, 1883, Gamble 12261 (CAL, DD). Salem district, Shevaroy
hills, s. die, Beddome s.n. (MH).
Notes: Klackenberg (1985) described E. grande to replace E. perrottetti sensu Wight (Icon. Pl. Ind. Orient. 4: 7. t.
1322. 1850) in South India. He (l.c.) separated his E. grande from E. tetragonum by its stem-clasping leaves, always
violet flowers and straight anthers against non-amplexicaul leaves, double coloured (white-violet) flowers and
declined anthers in the latter. However, in his description, the anthers are described as straight to some what curved
for E. grande. Similarly, the present study shows that the leaf character is also much variable in E. grande. Hence,
E. grande is reduced here to the variety of E. tetragonum.
12. Exacum travancoricum Bedd., Icon. Pl. Ind. Or. 1: 24. 1869; Klack., Opera Bot. 84: 68. 1985.
Exacum courtallense var. travancorica (Bedd.) C.B. Clarke in Hook.f., Fl. Brit. India 4: 97. 1883. Type:
Travancore hills, s. die, Beddome 47 (lecto, K!).
Figure 12
Small cushion herbs, 8–25 cm tall. Stems green, terete, highly branched. Leaves sessile-subsessile, succulent; lamina
spathulate, incurved, 2–4 × 0.5–1.2 cm, 3–nerved at base, acute at apex, truncate at base. Cymes often terminal or
axillary, solitary, pedicellate; pedicels 1–4.5 cm long. Calyx green, persistent, winged; wings semicordate, 1–3 mm
wide, tapering towards apex, prominently veined; lobes-4, elliptic-lanceolate, 1–2 × 0.5–1 cm, 3-nerved, acuteacuminate at apex. Corolla tube white, 3–5 mm long; lobes-5, blue, broadly elliptic-obovate, 1–2 × 0.6–1.5 cm,
obtuse at apex. Stamens-5; filaments short, pale green-white, 2–4 mm long; anthers yellow bottle shaped, erect,
opening by apical pores later widen to slits to the base, 1.5–2.5 mm long. Ovary green, obovate, 4–6.5 × 2.5–4.5
mm; style bluish white, 1–1.2 cm long, curved; stigma simple, capitate, faintly 2-lobed; lobes c. 0.1 cm. Capsule
brown, obovate, 4–10 × 4–6 mm. Seeds many, irregular or tetrahedral with shallowly sunken sides, 0.25–0.6 × 0.2–
0.4 mm; testa reddish brown.
Chromosome number: 2n = 68 (Mallikarjuna et al. 1987).
Flowering & fruiting: October–December.
Habitat: On wet rocks and open grasslands.
Distribution: Endemic to South India, critically endangered.
Specimens examined: Kerala, Thiruvananthapuram district, Agasthyamala, 06.02.1988, s.coll. 9476 (CALI), Ibid.,
01.07.1964, A.N. Henry 19189, Ibid., 06.10.1973, J. Joseph 44586 (MH); Ibid., 06.02.1988, N. Mohanan 9476,
Ibid., 19.10.1993, S. William Decruse 18402; Pongalapara, 25.08.1990, N. Mohanan 10043, Ibid., 14.11.1991, N.
Mohanan 10937 (TBGT); Travancore hills, s. die, R.K. Arora 3356 (CAL). Shimoga district, Kudajadri, 08.11.2013,
P.M. Shahina, A.P Janeesha. & H.S. Ashwini 134718 (CALI). Uttara Kannada district, Uttara s.coll. 33203, 33197
(MH). Wayanad district, Gurukula Botanical Sanctuary, 14.01.2013, P.M. Shahina & Santhosh Nampy 4975
(CALI). Tamil Nadu, Kanyakumari district, Muthukuzhivayal, 09.09.1976, A.N. Henry 48294 (MH).
Tinnevely district, Tinnevely, 22.05.1907, C.A. Barber 2888 (CAL).
Notes:- E. travancoricum is easily distinguished by its dense, cushion-like habit, succulent leaves and solitary
terminal flowers on long pedicels.
13. Exacum wightianum Arn., Ann. Sci. Nat., Bot. II, 11: 176. 1839; Klack., Opera Bot. 84: 74. 1985. Type:
Peninsula Indiae Orientalis, Wight s.n. (lecto, E!).
Exacum foliosum Griseb. in A. DC., Prodr. 9: 45. 1845. Type: Asia, Hugel (lecto, W!). Exacum atropurureum var.
palghatense Gamble, Fl. Madras 2: 874. 1923. Type: Palghat hills, s. die, Beddome 33 (lecto, MH!).
Figure13
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Figure 12. Exacum travancoricum Bedd.: A. Flowering twig; B. Flower; C. Calyx; D. Corolla opened; E. Stigma;
F. Fruit; G. Gynoecium; H. Stamens; I. Seeds (from Shahina P.M. & Santhosh Nampy 4975).
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Herbs, 20–120 cm tall. Stems 4-angular, winged (wings 2–6 mm broad), woody, branched basally and apically.
Leaves sessile; lamina broadly ovate, 2.5–8 × 1–3 cm, 3-nerved at base, acute-acuminate at apex; base attenuate.
Cymes usually terminal/axillary, 1–3-flowered; bracts ovate, 0.5–1.5 × 0.5–0.8 cm; pedicels 4-lineolate, 1–4 cm
long. Calyx green, persistent, dorsally winged; wings semi cordate at base, 1–1.5 mm wide; lobes-5, ovatelanceolate, 8–15 × 3–5 mm, acuminate at apex. Corolla tube white, 6–9 mm long, yellow at throat; lobes-5, blue,
broadly elliptic, 1.5–3.5 × 0.7–2 cm, margins wavy, cuspidate. Stamens-5; filaments pale green-yellow, 2–3 mm
long; anthers yellow, erect, linear, oblong, papillate, 6–9 × 1–2 mm long, dehiscence through apical pores. Ovary
green, oblong, 4–8 × 2–4 mm; style greenish white, 5–12 mm long, curved; stigma simple, rounded, faintly 2-lobed;
lobes c. 1 mm long. Capsule brown, drooping, oblong-globose, 8–15 × 3–8 mm, unilocular. Seeds many, irregular,
0.3–0.5 × 0.1–0.3 mm; testa brown.
Chromosome number: 2n = 68 (Mallikarjuna et al. 1987).
Flowering & fruiting: June–March.
Habitat: Along road sides, on road cuttings and in open grasslands, at altitudes above 1700 m.
Distribution: Endemic to southern Western Ghats, rare.
Uses: It is as an efficient antimicrobial therapeutic agent in acute anti inflammatory conditions (Arumugasamy,
2012).
Specimens examined: Karnataka, Mysore district, Nagavalli, 30.10.1969, S. Vijaya 16 (JCB). Kerala, Idukki
district, Devikolam, 27.12.1938, P. Kumara Pillai s.n. (TBGT); Idukki, 06.12.1987, P. Bharghavan 87353, Ibid.,
14.10.1989, P. Raghavan 90940 (MH); Kanthallur, 30.03.1978, Nambiar 00259 (KFRI); Maatupetti, 19.11.2012,
K.M. Manudev & P.M. Shahina 4957; Munnar, 05.11.1961, C.J. Saldanha 8042 (BLAT), Ibid., 15.06.1985, K.M.
Matthew 18469 (RHT), Ibid., 19.11.2010, Sheba M. Joseph 3973, Ibid., 15.11.2012, A.K. Pradeep 4950, Ibid.,
08.12.2010, P.M. Shahina & Santhosh Nampy 4119, Ibid., 21.01.2011, P.M. Shahina, Sandhya Vincent & Alfred
Joe 4167, Ibid., 18.11.2012, K.M. Manudev 4956; Silent Valley, 16.12.2012, K.M. Manudev & A.J. Robi 4968
(CALI). Kottayam district, Kottayam, 10.10.1963, K.M. Sebastine 17495, Ibid., 16.11.1965, B.V. Shetty s.n. (MH).
Thiruvananthapuram district, Ponmudi, 20.09.1968, K.M. Matthew 9258 (RHT). Tamil Nadu, Dindigul district,
Kodaikanal, 10.08.1959, C.J. Saldanha 4383 (BLAT), Ibid., 22.09.1956, K.M. Matthew 2668 (RHT), Ibid.,
15.02.1974, K.C. Sankaran 8867 (CALI), Ibid., 16.08.1975, K.M. Matthew 14812, Ibid., 26.09.1984, K.M. Matthew
40903, Ibid., 30.07.1985, S.J. Britto 41556, Ibid., 13.08.1985, K.M. Matthew 42004, Ibid., 06.09.1985, S.J. Britto
42162, Ibid., 28.11.1985, K.M. Matthew & N. Rajendran 43419, Ibid., 04.02.1986, K.M. Matthew & N. Rajendran
43961, Ibid., 13.06.1986, K.M. Matthew 45449, Ibid., 30.07.1986, K.M. Matthew 53701 (RHT); Pongalapara,
07.02.1988, s.coll. 9508 (CALI). Nilgiris district, Conoor, D.B. Deb 31728; Ebanad koil, Belta slopes, 15.09.1970,
G.V. Subba Rao 36621; Kodanad, 12.11.1970, E. Vajravelu 36853; Nilgiris, 09.12.1957, K.M. Sebastine 4848, Ibid.,
29.08.1970, B.D. Sharma 359114; Naduvatam, 29.08.1970, B.D. Sharma 35914 (MH). Kanyakumari district,
Anamalais, Akamalai, 15.12.1986, K.M. Matthew 18773; Kodayar, 18.01.1986, K.M. Matthew 18739;
Muthukuzhivayal, 20.10.1985, S. Sebastine 18639; Periyakulam, 09.02.1985, K.M. Matthew 40964 Subagun,
13.09.1959, s.coll. 1198; Tiger shola, 11.06.1986, K.M. Matthew 45430 (RHT). Tirunelveli district, 22.09.1916,
s.coll. 33188 (MH); Kaliyalpil, 01.06.1901, s.coll. 3023 (MH).
Notes:- Exacum wightianum is a showy plant with bright violet flowers. It is easily distinguished by its broadly
winged stem, sessile, leathery leaves, drooping fruits and anthers with a prominent papilla near the apex.
Acknowledgements:
We are thankful to Prof. K.M. Jayaram, Head, Department of Botany, University of Calicut for facilities; the
curators of BM, E, G-DC, HAL, K, K-W, L, LINN, S, U and W for the virtual images of type specimens and BLAT,
BSD, BSI, CAL, CALI, DEV, DD, FRC, JCB, KFRI, MH, RHT, RRLB, SNC, SKU and TBGT for permitting to
consult specimens; Dr. Jens Klackenberg (Stockholm) for kindly providing a copy of his monograph on Exacum;
Dr. N. Sasidharan (KFRI, Peechi) Mr. W.D. Theuerkauf (Gurukula Botanical Sanctuary, Periya), Dr. Sheba M.
Joseph (St. Mary‟s College, Bathery), Mr. Manudev K.M., Mr. Alfred Joe, Mrs. Janeesha A.P., Mr. Syam Radh S.,
Mr. Arun Kumar P.G. & Mr. Habeeb Rahman (Research Scholars, University of Calicut), Mr. Robi A.J., Mr. Dantas
K.J. (Research Scholar, KFRI), Mr. Prabhu Kumar K.M. (Scientist, CMPR, Kottakkal) and Ms. Ashwini H.S.
(Kuvempu University) for helping collections. SPM is thankful to the Kerala State Council for Science Technology
and Environment for Fellowship in Taxonomy (001/FSHP/09/CSTE).
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Figure 13. Exacum wightianum Arn.: A. Flowering twig; B. Flower; C. Calyx; D. Stamens; E. Corolla opened; F.
Gynoecium; G. Stigma; H. Fruit; I. Seed (A from Manudev K.M. & Robi A.J. 4968; B-I from Shahina P.M. &
Santhosh Nampy 4119)
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