Revision of the subtribe Loxotidinae (Gesneriaceae) of Indian part of Eastern Himalaya.

Abstract

Loxotidinae is a very interesting group of the family Gesneriaceae. Loxotidinae belongs to the tribe Epithemateae under the
subfamily Didymocarpoideae. A total of three (3) species under the subtribe Loxotidinae have been recorded from Indian part of
Eastern Himalaya. Critical analysis of the recorded species shows some unusual morphology such as strong anisophylly, pseudoracemose
in

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Introduction
Loxotidinae belongs to the tribe Epithemateae under the subfamily
Didymocarpoideae of the family Gesneriaceae (Möller and Clarke,
2013). Gesneriaceae was traditionally divided into two subfamilies
viz. (i) Gesnerioideae (New World) with isocotylous seedling and
infer ior ovary and (ii) Cyrta ndroidea e ( Old Wo rld) with
anisocotylous seedling and superior ovary (Clarke, 1883).
Loxotidinae is a monotypic subtribe with only single genus
(Rhynchoglossum) and 10 species distributed worldwide (Möller
and Clarke, 2013). Gesneriad genera are generally restricted to
eit h er New W orl d o r Old W orl d e xce p t the g e ner a
Rhynchoglossum and Epithema. Although other species of
Rhynchoglossum are Old World in distribution, R. azureum has
been reported from New World (Central America to Venezuela). C.
B. Clarke in Flora of British India (vol 4, 1884) recorded only one
species R. obliquum from India. B. L. Burtt in 1962 merged the
genus Klugia into the Rhynchoglossum thus transferring the
Klugia ampliata to R. ampliatum. Rao and Joseph recorded R.
lazulinum from Arunachal Pradesh in 1967.
Old World gesneriads have a number of odd genera with unique
morphological features. Gesneriaceae is characterised by pair
owered cymose inorescence but in Rhynchoglossum it is
reduced to single ower with pseudoracemose inorescence.
Extreme anisophylly is noticed in this genus where one leaf from
each node is completely reduced while the other strongly
asymmetrical foliage leaf matures being placed in two almost
opposite ranks.
The three species of Rhynchoglossum from the Indian part of
Eastern Himalaya have been discussed critically with key and
comparative analysis.
Material and Methods
This work is based primarily on the morphological studies of
herbarium specimens as well as literature and fresh specimens
collected during eld survey. Important herbaria of Botanical
Survey of India visited for herbarium specimens included CAL,
BSHC, ASSAM, ARUN and LBG.
Taxonomic studies of Rhynchoglossum
Rhynchoglossum Blume Bijdr., Fl. Ned. India 741.1826; C.B.
Clarke, Commelyn. Cyrtandr. Bengal. 123.1874., in A. & C. de
Candolle, Monogr. Phan. 5: 161. 1883 & in Hook. f. Fl. Brit. India 4:
367. 1884; Wang et. al. in Fl. China 18: 399. 1998; O. M. Hillard in
Grierson and Long, Fl. Bhutan 2(3): 1327. 2001.
Type: Rhynchoglossum obliquum Blume
Perennial or annual monocarpic herbs, sparsely indumentum,
eshy-succulent. Leaves alternate or opposite, unequal sided,
short petiolate, lamina ovate-cordate, texture thin and delicate.
Inorescence unilateral terminal or axillary raceme, bracts
su bt en di ng , li ne ar, displaced on to the pe di ce ls . Ca ly x
campanulate, lobes 5, longer or shorter than tube. Corolla strongly
zygomorphic, tube cylindrical, bluish or bluish violet, limb strongly
bilabiate, upper 2-lobed, lower 3-lobed, larger. Stamens 2 or 4
fertile, included, anthers opposed in pairs, cells conuent. Disc
cupuled. Ovary ovoid, style linear, stigma obscurely bilobed.
Capsules included within calyx, ellipsoid, loculicidally 2-valved.
Seeds small, many, ellipsoid, minutely rugulate.
Distribution: Rhynchoglossum with ca 10 species (Möller and
Clarke, 2013) is distributed in Indo-Malayan region and tropical
region; 3 species have been recorded from North Eastern India
including West Bengal.
Habitat: On wet and shady rock, in forest or open shady places,
usually in lowlands.
Key to the species
1 a .
Stamens4……………………………………………………………
…………………….2
1b. Stamens
2…………………………………………………………………….3
R. obliquum
2a. Inorescen ce termi nal raceme; o wers showy bl ue-
violet..………………...2 R. lazulinum
2b. Inorescence axillary or terminal raceme; owers whitish
blue………...…1 R. ampliatum
1. Rhynchoglossum ampliatum (C. B. Clarke) B.L. Burtt Notes
Roy. Bot. Gard. Edinburgh 24. 168.1962; Klugia ampliata C. B.
Clarke, Monogr. Phan 160. 1883 and in Hook f., Fl. Brit. India 4:
367. 1884.
Type: Mis hmee Hi lls , As sam , Ind ia , W. Gr if th 3 84 6
(K000858040!)
Herbs, stem glabrous. Leaves ca. 15 x 8 cm, upper and lower
surface glabrous, petioles 1-4 cm long. Inorescence axillary or
terminal raceme, bracteole conspicuous, persistent, peduncles 1-2
Original Research Paper Biology
Revision of the subtribe Loxotidinae
(Gesneriaceae) of Indian part of Eastern Himalaya
Susmita Roy
Department of Botany, Netaji Nagar College for Women, Regent Estate,
Kolkata 700092
T K Paul
Botanical Survey of India, Howrah 711202
ISSN - 2250-1991 | IF : 5.761 | IC Value : 79.96
Volume : 6 | Issue : 3 | - 2017March
KEYWORDS
Rhynchoglossum, Loxotidinae, Gesneriaceae, taxonomic revision.
ABSTRACT
Loxotidinae is a very interesting group of the family Gesneriaceae. Loxotidinae belongs to the tribe Epithemateae under the
subfamily Didymocarpoideae. A total of three (3) species under the subtribe Loxotidinae have been recorded from Indian part of
Eastern Himalaya. Critical analysis of the recorded species shows some unusual morphology such as strong anisophylly, pseudo-
racemose inorescence etc. Detailed morphological description, correct accepted name, synonym, key to the species, phenology
and distribution have been discussed here.
Sobhan Kumar
Mukherjee
Taxonomy and Biosystematics Laboratory, Department of Botany, University of
Kalyani, Kalyani 741235, Nadia,
PARIPEX - INDIAN JOURNAL OF RESEARCH | 545

cm long, pedicels 0-4 mm long. Calyx ca. 15 mm long, 5-lobed,
lobes as long as the tube, lanceolate, sub-equal, cylindrical, deep
green. Corolla bluish white. Stamens 4 fertile, anthers coherent.
Capsule ovoid oblong within acrescent calyx.
Ditribution: India: Arunachal Pradesh
2. Rhynchoglossum lazulinum A. S. Rao et J. Joseph in Bull. Bot.
Surv. India 9 (1-4): 280. 1967; H. J. Chaudhury et. al. in G. S. Giri et.
al. Mat. Fl. Arunachal Pradesh 2: 233. 2008.
Type: Krishna 36 km from Bhallukpong, on the way to Sessa,
Kameng district, NEFA, 1250 m, 10.9.1964, Joseph 39716A (CAL,
HOLOTYPE)
Succulent herbs, stem 50-100 cm high, cylindrical, smooth.
Leaves alternate as well as opposite, long petioled at lower nodes
to sessile near peduncle, broadly elliptic, dark-green, 9-2.4 x 3.5-
10 cm, membranous, apex acute to acuminate, base unequal,
subcordate, margin entire. Inorescence terminal racemes,
glabrous, bract ca 4 mm long, peduncle 14.5-25.5 cm long,
pedicel stout ca 1 cm long, bluish violet. Calyx ca 4 cm long,
infundibulum, conspicuously ridged, green, calyx lobes much
smaller than tube. Corolla ca 6 cm long, bilabiate, bright blue to
violet, glabrous, prominently bent at the throat, lower lip 3 lobed,
upper 2 lobed. Stamens 4, didynamous, anthers conuent, at.
Disc cuplike. Ovary ovoid, ca 1 cm high, style stout, ca 2.5 cm
long, stigma bilobed. Capsule ca. 2 cm long, ellipsoid, within
persistent calyx, seeds many, small, ovoid.
Habitat: Along hill slopes & underneath primary forest on thick
humus rich soil.
Fl. & Fr.: August-November
Distribution: India: Arunachal Prdesh. Endemic to India.
Exsicc: Lower Subansiri, 7.9.1983, G. D. Pal 299 (ARUN, acc no-
2962); Way from Palin to Deed, Arunachal Pradesh, 13.9.1983 G.
D. Pal 510 (ARUN, acc no-2964); 5 km from Habia Basti, Arunachal
Pradesh, 26.10.85 G. D. Pal 1929 (ARUN, acc no-2965).
3. Rhynchoglossum obliquum Blume, Bijdr. 14: 741. 1826; C. B.
Clarke in Hook f., Fl. Brit. India 4: 367. 1884; C. E. C. Fisch in Rec.
Bot. Surv. India 12(2): 118. 1938; Kanjilal et. al., Fl. Assam 3: 398.
1939; Rhynchoglossum obliquum var. parviora C. B. Clarke in A.
DC. Monogr. Phan. 5: 162. 1883; Matthew, Fl. Pl. Kurseong 76.
1981; G. P. Sinha in Singh et. al. Fl. Mizoram 2: 211. 2012; H. J.
Chaudhury et. al. in G. S. Giri et. al. Mat. Fl. Arunachal Pradesh 2:
233. 2008; A. Mukherjee et. al. in Pleione 2 (2): 159. 2008.
Herbs 30-70 cm. high. Stem soft, succulent. Leaves broadly
ell ipt ic, ap ex acute to acu min ate , margin smooth, bas e
prominently oblique, 5-17 x 2.5-5.5 cm, petiole 0.5-2.5 cm,
alternate, surface sparsely hairy. Inorescence axillary and
terminal raceme, rachis hairy. Calyx 5-lobed, lobes 4 mm long,
apex acuminate; Corolla 0.9 cm., blue. Stamen 2 perfect, 3 mm.
long, anther dorsixed, conjoint. Carpel 7 mm. long, ovary 2.5
mm. Capsules globose with persistent style and stigma.
Habitat: Along hill slopes & underneath primary forest on thick
humus rich soil.
Fl. & Fr.: July-December
Distribution: INDIA: India West Bengal (Darjeeling), Sikkim,
Assam , A runac hal Prad esh; NEPAL , B HUTAN, CHINA ,
MYANMAR, TAIWAN, INDONESIA, THAILAND, PENINSULAR
MALAYSIA, LAOS, VIETNAM, CAMBODIA.
Exsicc: Darjeeling, 1300 m, G. King 13722 (CAL); Mahananda
Wildlife Sanctuary, Darjeeling, 24.09.07 T. K. Paul & Anant Kumar
A2545 (CAL); Dampa T. R., 920 m, 21.9.2006, B. K. Sinha & Odyuo
112749 (ASSAM, acc no-71167); Subansisri F. D., 290m,
24.9.1959, G. Panigra hi 19323 (ASSAM, acc no-16274);
Nagaland, 12.10.1977 C. L. Malhotra 75227 (ASSAM, acc no-
68773 ); Howa-Pani, Arunachal Pradesh, 18.9.07 R. K.
Choudhary18673 (ARUN, acc no-7977); L. Subansiri, New
Itanagar, 8.8.78., G. D. Pal. 76029 (ARUN, acc no-2937); Nyapin to
Paji, 25.11.1964, A. R. K. Sastry 40905 (ARUN, 2967)
Discussion and Conclusion
Rhynchoglossum Blume and Klugia Schlechtd. are closely related
as stated by Clarke (1883) emphasized on the number of fertile
stamens durin g c lassica tion a nd thus kept Klugia and
Rhynchoglossum as separate genera. But, Burtt (1962) considered
corolla character in addition to stamens during classication of the
gen us Rhynchoglossum. H e i n clu de d K lug ia w ith in
Rhynchoglossum in Notes from the Royal Botanic Garden
Edinburgh. Present paper described 3 species of Rhynchoglossum
viz., R. obliquum, R. ampliatum and R. lazulinum found in the
study area. Out of the 3 species R. obliquum is widely distributed
while R. lazulinum and R. ampliatum have been reported only from
Arunachal Pradesh (Fig 1).
Fig 1. Distribution map of Rhynchoglossum in Indian part of
Eastern Himalaya
, R. ampliatum; R. lazulinum R. obliquum.
R. ampliat um was f ormer ly kn own as K lugia am pl iata.
Comparative study of the three species (Table 1) shows that R.
obliquum has 2 fertile stamens , whereas R. lazulinum and R.
ampliatum have 4 fertile stamens.
Table 1: Comparative study of R. ampliatum, R. lazulinum
and R. obliquum
From the eld visit only Rhynchoglossum obliquum was collected
(Fig 2).
Fig 2. Rhynchoglossum obliquum Blume
ISSN - 2250-1991 | IF : 5.761 | IC Value : 79.96
Volume : 6 | Issue : 3 | - 2017March
Characters
R. ampliatum
R. lazulinum
R. obliquum
Habit
Succulent herbs
Succulent herbs
Succulent herbs
Leaves
Surface glabrous
Surface glabrous
Surface sparsely
hairy
Inorescen
ce
Axillary or
terminal raceme
Terminal raceme
Axillary or
terminal raceme
Stamens
Fertile 4, anthers
coherent
Fertile 4,
didynamous
Fertile 2
Calyx
Lobes as long as
the tube,
campanulate
Lobes much
smaller than
tube,
infundibuliform
Calyx cleft,
campanulate
546 | PARIPEX - INDIAN JOURNAL OF RESEARCH

R. lazulinum is endemic to Arunachal Pradesh (Singh et. al., 2015).
It is locally known as “Taigium” by Nyshi tribe of Arunachal
Pradesh. There is no record of preserved specimens of R.
ampliatum in the studied herbarium. The description has been
done on the basis of literature (REF). R. lazulinum recorded only
from Arunachal Pradesh eld Station Herbarium (ARUN). Extensive
survey in the far ung areas of Ar unachal Pradesh and
conservation of R. lazulinum and R. ampliatum is highly warranted.
References
1. Möller M and Clarke JL. 2013. The state of molecular studies in the family
Gesneriaceae: a review. Pp. 95–125 in JR. Clarke, ed. Proceedings of the World
Gesneriad Research Conference 2010. Selbyana. 31:65–253.
2. Clarke CB. 1883. Cyrtandreae. In: Candolle ALLP de & Candolle ACP de,
Monographiae Phanerogamarum. 5: 1–303.
3. Clarke CB.1884 ('1885'). Gesneraceae. Pp. 336-375 in: Hooker, J.D. (ed.) The Flora
of British India, vol. 4. London: Reeve.
4. Bur tt B L. 1 962. Stu dies in th e Ges neria ceae of t he Old World XXI II:
Rhynchoglossum and Klugia. Notes Roy. Bot. Gard. Edinburgh. 24: 167-171.
5. Rao AS and Joseph J. 1967. Rhynchoglossum lazulinum - A New Species of
Gesneriaceae. Nelumbo. 9(1-4): 280
6. Singh P, Karthigeyan K, Lakshminarasimhan P, Dash SS. 2015. Endemic Vascular
Plants of India. Botanical Survey of India. Pp 165-167
ISSN - 2250-1991 | IF : 5.761 | IC Value : 79.96
Volume : 6 | Issue : 3 | - 2017March
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