Coelogyne tripurensis Adit, 2024

Adit, Arjun & Kumar, Pankaj, 2024, Taxonomy of Coelogyne section Fuliginosae (Orchidaceae): new species, notes, resurrections and typifications, Phytotaxa 668 (1), pp. 81-98 : 92-95

Coelogyne tripurensis Adit , sp. nov.

( Figs. 6 , 7A )

TYPE. INDIA . Tripura, North Tripura district, Jampui Hills, Phuldungsei (23°48.835’N, 92°15.564’E, 845 m), 8 Jan. 2018, Arjun Adit 2104 ( DUH14483 - Holotype; Supplementary fig. 1) .

Herb epiphytic, perennial, erect or pendulous. Rhizome creeping plagiotropic, semi-woody, 40–50 cm long, 0.4–0.6 cm in diameter, covered with brown remnant bracts, several pale brown roots arising from nodes and internodes. Pseudobulbs erect, oblong and inflated, green, 2-leaved, 2.6–3.2 cm apart, cylindrical, 6.8–7.3 cm in length, 2.6–3.9 cm in diameter, with grey papyraceous bracts 1–2 cm long. Leaves two, bottle green, glabrous, apical, petiole 0.8–1.2 cm long, oblong or lanceolate with parallel venation, lamina 12.2–13.4 × 2.8–3.3 cm, margin entire, apex acute and base decurrent. Inflorescence hysteranthous, originating from apex of a mature pseudobulb, erect, consisting of 2–3 flowers in raceme, on 1.1–1.9 cm long green axis, enveloped at base with fleshy brown-colored tiny bracts. Flower pedicellate, bracteate, 4.2–4.9 cm across, zygomorphic, triangular, pale yellow with a reddish-brown center giving a bulls-eye effect. Bract one per flower, caducous, brown. Sepals sub-similar, spreading, ovate with shortly acuminate apices, 2.9–3.6 × 1.6–2.2 cm, pale yellow with faint linear markings. Petals linear and recurved, 1.8 – 2.4 cm long, white. Labellum broadly ovate, 2.3–2.7 × 2.5–3.1 cm, 3-lobed, pubescent; lateral lobes erect, ovate, pale-white with red longitudinal markings, 1.1–1.4 × 0.8–1.1 cm, margins shortly pectinate, apex obtuse; mid-lobe elliptic, 1.1–1.4 × 0.7–0.9 cm, margins pilose fimbriate, apex oblique; labellum keel lamellae longitudinally arranged, maroon-red, two running throughout the length of the labellum and one travelling only one-third length, two longer lamellae dentate near the base and undulate from the middle. Column convex, 1 cm long, winged at apex, smooth, sessile, white, bright scarlet near the base; anther cap hemispheric, pale yellow, 0.3 cm in diameter; pollinia 2, yellow, lenticular, with amorphous viscidium. Fruits unknown.

RECOGNITION. Coelogyne tripurensis can be distinctly identified by its oblong, angular, inflated pseudobulbs; subsimilar, ovate, shortly acuminate sepals; large, triangular flowers; completely reflexed petals; lateral lobes more than 2/3 the length of labellum; oblong, obliquely subacute midlobe of labellum; and three, distinct, undulate, un-interrupted labellum keels with the middle keel more than 1/3 the length of lateral keels.

DISTRIBUTION. India (Tripura: North Tripura district: Kanchanpur sub-division: Jampui hills).

SPECIMEN EXAMINED. INDIA . Tripura, Jampui Hills, Phuldungsei (23°48.835’N, 92°15.564’E, 845 m), 8 Jan. 2018, Arjun Adit 2104 (DUH!).

HABITAT. Rarely observed on moss covered trees in the moist broadleaf forest at Phuldungsei, Jampui hills.

CONSERVATION STATUS. Only one small population with fewer than 15 mature individuals has been observed in the type locality which is situated on a hill range of less than 70 km 2 area. The general area is disturbed due to eco-tourism attraction (highest peak of the state), which has led to rapid development projects. The single population with limited mature individuals has an area of occupancy ( AOO) of 4 km 2, and there is inferred continuous decline in the quality of habitat, due to which the single locality is considered as single location. Subsequent visits during years following its discovery revealed urbanization activities in the type locality, leading to a possibility that the population might dwindle in the near future. The species is thus assessed as Critically Endangered [ CR B2 ab(iii,v); C2 a(i); D] following the IUCN Red List criteria ( IUCN Standards and Petitions Committee 2022). Due to its threatened status, general geocoordinates have been mentioned here .

FLOWERING PHENOLOGY. Peak flowering of the species is observed between early January and mid- February

ETYMOLOGY. The specific epithet is named after Tripura, a state in North-East India where the type locality is situated.

COMMON NAME. Tripuri Coelogyne

NOTES. The new species superficially resembles C. fimbriata , C. fuliginosa and C. ovalis , however it differs in several characters (see Table 1). Coelogyne tripurensis is distinguishable from these three due to its angular and inflated pseudobulb, fewer flowers in an inflorescence, completely reflexed petals, densely fimbriate labellum with longer lamellae, larger lateral lobes of labellum, a distinct median keel that is one-third the length of lateral keels and a shorter column. Moreover, it flowers in January–February, while the other three flower between September and December.

It differs from C. fimbriata due to its longer leaves, larger flowers, ovate sepals, undulate lateral keels and presence of a median keel. It differs from C. fuliginosa due to its smaller flowers, ovate sepals and undulate and un-interrupted keels. It differs from C. ovalis due to its longer inflorescence, sub-similar sepals, obliquely sub-acute labellum midlobe and a distinct median keel.

A comparative account of labellum morphology, key distinguishing traits within Coelogyne section Fuliginosae is diagrammatically represented in Fig. 8 .

Figures

FIGURE 6. Coelogyne tripurensis Adit sp. nov. A. Two species are clearly visible in the natural habitat, C. tripurensis (black arrow) and co-occurring C. fimbriata (white arrow). B. Habit of C. tripurensis with frontal view of flower in inset.

FIGURE 7. Comparative floral morphology (whole mounts of flower and labellum) of A. Coelogyne tripurensis, B. C. ovalis, and C. C. fimbriata. Note: Image of C. tripurensis labellum on this plate is taken from specimen stored in 70% alcohol to show clear pattern of veins and keels. Single scale has been used for size comparison between the species.

FIGURE 8. Comparative labellum morphology of species in Coelogyne section Fuliginosae. A. C. chrysotropis: i. from Schlechter (1911: fig. 7C(21)); ii. Type drawing (Schlechter 1911); B. C. leungiana: i. from P. Kumar 12008 (KFBG!); ii. Original drawing from Hu (1972); C. C. fuliginosa: i. from Das & Jain (1980: fig. 9a), ii. from Clayton (2002: fig. 7(4)); D. C. pallens: i. From Clayton (2002: fig. 7(6)); E. C. ovalis: i. P. Kumar KFBG423 (KFBG), ii. from Das & Jain (1980: 8a), iii. from Clayton (2002: fig. 7(3)), iv. from Seidenfaden (1975: fig. 6b); F. C. fimbriata: i. P.Kumar 12026 (KFBG), ii. from Das & Jain (1980: 7b), iii. from Clayton (2002: fig. 7(2)), iv. from Seidenfaden (1975: fig. 4c); G. C. triplicatula: i. from Pelser et al. (2000: 5a), ii. from Clayton (2002: fig. 7(7)); H. C. phitamii: i. from Averyanov et al. (2023: fig. 1G), ii. from Seidenfaden (1975: fig. 4d); I. C. tripurensis: i. from holotype, Arjun Adit 2104 (DUH!), ii. based on holotype, Arjun Adit 2104 (DUH!) by Pankaj Kumar. Note: figure not to scale.