Pleione 12(2): 333 - 336. 2018.
© East Himalayan Society for Spermatophyte Taxonomy
doi: 10.26679/Pleione.12.2.2018.333-336
ISSN: 0973-9467
Thrixspermum merguense (Hook.f.) Kuntze [Orchidaceae:
Epidendroideae: Vandeae: Aeridinae] - an addition to the Orchid
flora of Mainland India
Khyanjeet Gogoi
TOSEHIM, Regional Orchids Germplasm Conservation & Propagation Centre (Assam Circle),
Daisa Bordoloi Nagar, Talap, Tinsukia 786 156, Assam, India
E-mail: khyanjeetgogoi@gmail.com
[Received 14.11.2018; Revised 21.11.2018; Accepted 22.11.2018; Published 31.12.2018]
Abstract
Thrixspermum merguense (Hook.f.) Kuntze (Orchidaceae) is reported as a new distributional
record to the orchid flora of Mainland India from Assam. A detailed description of the species
along with a plate of colour illustrations of habit and dissected floral parts is provided.
Key words: Thrixspermum merguense, Orchidaceae, new record, Mainland India.
INTRODUCTION
During a field trip to the Joypur Reserve Forest in Dibrugarh district of Assam in August
2018, the author collected an epiphytic orchid in its vegetative condition. The orchid was
planted at the Regional Orchids Germplasm Conservation and Propagation Centre (Assam
Circle), Assam, where it was flowered during October 2018. On the basis of available literature
(Hooker 1890; King & Pantling 1898; Kataki 1986, Seidenfaden 1988; Seidenfaden & Wood
1992; Pearce & Cribb 2002; Kumar & Kumar 2005; Lucksom 2007; Chen et.al. 2009) and
critical examination of the flowers, it was identified as Thrixspermum merguense (Hook.f.)
Kuntze which is known to occur so far from Andaman Islands, Myanmar, Vietnam, Malaysia,
Sumatra, Java, Krakatu, Taiwan and Philippines (Mathew & Abraham 1996). Hence the
present report of its occurrence from Assam forms a new distributional record to the state
as well as for the Indian mainland. A detailed description of the taxon with information on the
habitat, distribution, phenology etc. along with a plate of colour illustrations has been provided
in the present paper. The voucher specimen is deposited in the ASSM Herbarium of Botanical
Survey of India at Shillong, Herbarium of the Department of Life Science, Dibrugarh University
(DU) and Herbarium of The Orchid Society of Eastern Himalaya (TOSEHIM), Regional
Orchid Germplasm Conservation and Propagation Centre (Assam Circle), Assam.
The genus Thrixspermum Lour. (Orchidaceae: Epidendroideae: Vandeae: Aeridinae)
comprises of around 100 species distributed widely from the Himalayas to Philippines and
tropical Islands of S.W. Pacific (Chen et al. 2009). So far, 16 species are reported from
India (Misra 2007; Mainaet al. 1998; Mao et al. 2011; Gogoi 2011, 2018; Gogoi &Yonzone
2015; Kumar et al. 2017) of which 6 species viz. T. acuminatissimum (Blume) Reichb.f., T.
centipede Lour., T. formosanum (Hayata) Schltr., T. musciflorum A.S. Rao & J. Joseph, T.
pygmaeum (King & Pantl.) Holttum and T. trichoglottis (Hook.f.) Kuntze. occurs in Assam
(Gogoi 2018). The present find of Thrixspermum merguense from Joypur Reserve Forest,
forms a new record to the state of Assam and also for the Mainland India thereby making
the total number of species in Assam increased to seven.
334
Record of Thrixspermum merguense for mainland India
1
2
3
4
A
5
PLATE - I. Thrixspermum merguense (Hook.f.) Kuntze: Figs. 1 – 5: 1. Habit; 2. Flower with
inflorescence; 3. Close-up of flower; 4. Close-up of column and lip; 5. Figs. A – K: A. Inflorescence;
B. Flower ; C & D. Perigone, ventral and dorsal views; E. Lip with ovary and column; F,G & H.
Different views of lip; I. Longitudinal section of the lip ; J. Ovary and column; K. Column.
Thrixspermum merguense (Hook.f.) Kuntze, Revis. Gen. Pl. 2: 682. 1891; Seidenf. in
Opera Bot. 95: 159, f. 97, t. XVI d.1986 & Opera Bot. 144: 406. 1992; Averyanov in Komarov
Bot. Inst. Leningrad 96. 1988; Garnt, Orch. Burma 303. 1895. Sarcochilus merguensis
Hook.f., Fl. Brit. India 6: 40. 1890. Dendrocolla merguensis (Hook.f.) Ridl., J. Linn. Soc.,
Bot. 32: 380. 1896. Thrixspermum comans J.J.Sm., Bull. Dép. Agric. Indes Néerl. 13: 61.
1907. Thrixspermum bicristatum Ames, Orchidaceae 5: 202. 1915. Sarcochilus
kusukusensis Hayata, Icon. Pl. Formosan. 6: 83. 1916. Thrixspermum kusukusense
(Hayata) Schltr., Repert. Spec. Nov. Regni Veg. Beih. 4: 274. 1919. Thrixspermum comans
var. bicristatum (Ames) L.O. Williams, Bot. Mus. Leafl. 6: 80. 1938. Ascochilus pulvinatus
Guillaumin, Bull. Mus. Natl. Hist. Nat., sér. 2, 36: 539. 1965. [PLATE – I]
Khyanjeet Gogoi
335
Plants epiphytic; stems 2–3 cm, with several leaves. Leaves nearly basal, lanceolate
or elliptic lanceolate, narrowly oblong,2–6 × 0.5–0.6 cm, fleshy, apex obtuse and slightly
bilobed, sheathing at base, midrib prominent. Inflorescence suberect or ascending, 3.5–5 cm,
few flowered; rachis slightly thickened distally; floral bracts not distichous, broadly lanceolate,
acute or acuminate, scalelike, 0.2 × 0.1cm. Flowers contiguous, opening successively, lasting
nearly half a day, yellow,with red stripes on lateral lobes and orange-yellow on midlobe of lip.
Dorsal sepal oblong or ovate-oblong, 0.4–0.5 × 0.2–0.3 cm, obtuse; lateral sepals slightly
oblique, similar to but slightly wider than dorsal sepal, obtuse. Petals obovate-oblong, 0.4–0.5
× 0.2–0.3cm; lip triangular, 0.3 × 0.5 cm, saccate at base, margin 3-lobed; lateral lobes erect,
large, obtuse; mid-lobe 0.1 × 0.2cm, truncate; disk with 2 conic calli and 3 tufts of white
hairs. Column very short, 0.2 cm, foot short. Pollinia 4, in two pairs.Capsule about transverse
to the rachis, 2.5 cm long, cylindric, linear, striated, with short beak at the apex.
Specimen Examined: Assam, Joypur Reserve Forest, Gogoi 00803, 8th October 2018
[ASSAM, DU, TOSEHIM]
Distribution in India: Assam and Andaman Islands.
General Distribution: India, China, Indonesia, Malaysia, Myanmar, Philippines, Thailand
and Vietnam.
Habitat: Epiphytic on tree-main trunks or branches.
Flowering: June – November.
Status: Rare.
Acknowledgements
The author is thankful to Dr. A. N. Rao for his very useful advices.
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Khyanjeet Gogoi