Thrixspermum formosanum (Hayata) Schltr., Repert., 2019

Thrixspermum formosanum (Hayata) Schltr., Repert. View in CoL Spec. Nov. Regni Veg. Beih. 4: 273. 1919; H.J.Su, Fl. Taiwan 5: 1049. 1978; S.C.Chen & J.J. Wood, Fl. China 25: 468. 2009; K.Gogoi & R.Yonzone, McAllen Int. Orchid Soc. J. 16(1): 12. 2015. Fig. 1 View Fig c-e

Small, epiphytic herbs, 6–9 cm tall. Roots 3.4–5.3 cm length, 0.2–0.3 cm in diam., radicosus, white. Stems ascending, 1.3–2.2 × 0.4–0.6 cm. Leaves distichous, 1.3–4.6 × 0.3–0.5 cm, linear-lanceolate, acute, jointed at base, thick and fleshy, midrib grooved ventrally, convex dorsally, green, spotted with purple. Inflorescence axillary racemes at lower nodes, shorter than leaves; peduncle 2.5 cm long, suberect, slender, straight, with 2 sterile bracts; rachis short, 0.3 cm long, green, thickened, few flowered, opening successively, lasting half a day; floral bracts few, c. 0.1 cm long, broadly ovate-triangular, acute at apex, green, persistent on rachis. Flowers c. 1.3 × 1.0 cm, fragrant; pedicel plus ovary 0.5 cm long, greenish brown. Sepals subsimilar, gland dotted; dorsal sepal 0.5–0.6 × 0.2–0.3 cm, oblong, obtuse; lateral sepals 0.5–0.6 × 0.2–0.4 cm, obliquely obovate, obtuse at apex. Lateral petals 0.6–0.7 × 0.1–0.2 cm, falcate-oblong, obtuse; lip white with brown stripes, saccate at base, 3-lobed; lateral lobes erect, 0.2–0.3 × 0.3–0.4 cm, subovate, obtuse; mid-lobe inconspicuous, disc pubescent; callus running from base to mid-lobe, apex of callus protruding, notched below mid-lobe; sac 0.4–0.6 cm long, cylindric, shallowly bilobed at base; column short, c. 0.15 cm long, foot c. 0.2 cm long, white. Anther cap sub-orbicular, white; pollinia 4, in two nearly equal pairs, attached by a short and broad stipe to a solitary viscidium. Capsules 4.5–7.3 × 0.3–0.4 cm, linear, cylindrical.

Flowering & fruiting: April-May.

Habitat: A rare epiphytic orchid found growing on moss covered tree trunks in evergreen forest at elevations between 1950 and 2300 m.

Distribution: India , China, Taiwan and Vietnam.

Specimen examined: INDIA , Tamil Nadu, Nilgiri Biosphere Reserve, Mukurthi National Park , 11°15′ 31′′ N, 76°30′ 14′′ E ± 2236 m, 18.11.2018, S. Kaliamoorthy & T.S. Saravanan 109641 (MH) GoogleMaps .

Conservation status: Less than 25 mature individuals were noticed during the field survey at Mukurthi National Park. Extensive field study in similar habitats in the adjacent localities is required to determine its exact IUCN threat status. Live specimens brought from the study area are being multiplied and maintained as germplasm collections at NOEG, BSI, SRC, Yercaud.