Volume 12 > Part 3 > Year 2022 > Page 997 > Orchidaceae > Thelasis

5. Thelasis pygmaea (Griff.) Blumewfo-0001254968

Fl. Javae, nov. ser.: 22. 1858; Hook.f., Fl. Brit. India 6: 86. 1890; B.Grant, Orchids Burma: 315. 1895; Holttum, Rev. Fl. Malaya 1, ed. 2: 550. 1957; Seidenf., Opera Bot. 89: 156. 1986; Aver., Prelim. List Vietnam. Orchids 2: 92. 1988; Seidenf. & J.J.Wood, Orchids Penins. Malaysia Singapore: 341, fig. 150d–f. 1992; N.Pearce & P.J.Cribb, Fl. Bhutan 3(3): 399. 2002; S.C.Chen & J.J.Wood in Z.Y.Wu et al. (eds.), Fl. China 25: 366. 2009.— Euproboscis pygmaea Griff., Calcutta J. Nat. Hist. 5: 371, t. 26. 1845. Fig. 547.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Epiphytic or lithophytic herb, 3–15(–22) cm tall. Pseudobulbs crowded, green, globose-ovoid, rugose, 0.4–1 cm tall, 0.5–1.2 cm in diameter, sheathed in a papery bract, 1-leaved (rarely 2-leaved) at apex. Leaf erect, light green, linear-oblong, sheathed and with a distinct abscission line at base, 2.9–8.5(–13) by 0.4–1.1(–1.5) cm, leathery, obtuse. Inflorescence arising from base of pseudobulb, green, flexuous and often recurved near the base of the rachis, 3.5–10.5(–23.8) cm long, bearing 1–3 sterile sheathing bracts, with 4–48 flowers in a dense, compressed to somewhat elongate head; rachis 0.5–3.8(–6) cm long; floral bracts green turning purple-brown, spreading, persistent, ovate, 1–2.5 mm long, acute or acuminate. Flowers non-resupinate, not opening widely, 2.2–7.4 mm long, cream to yellow-green. Sepals ovate-lanceolate, 1-veined, acute; dorsal sepal membranous, connate with the lateral sepals only at the very base, 2.2–3 by 0.7–1.1 mm; lateral sepals fleshy, cymbiform and deeply concave, connate for one third of their length or more, 2.8–3.4 by 1–1.5 mm, keeled outside. Petals membranous, oblong-ovate, 1.8–2.5 by 0.5–0.8 mm, slightly recurved at apex, 1-veined, obtuse or acute. Labellum shortly clawed, ovate-triangular, 2–2.8 by 1–1.5 mm wide, slightly concave, margins rolled upwards, ecallose, 3-veined, acute. Column 1–1.5 mm long; pollinarium 0.7–1.2 mm long. Ovary and pedicel flattened, ridged, 1.5–4.5 mm long. Capsule ridged, 1.8–5 mm long.

Thailand : NORTHERN: Mae Hong Son, Chiang Mai (Doi Chiangdao), Tak (Ban Mae La Mung Khi); EASTERN: Nakhon Ratchasima (Khao Yai); SOUTH-WESTERN: Kanchanaburi (Huai Bankau), Phetchaburi; SOUTH-EASTERN: Chanthaburi (Khao Soi Dao); PENINSULAR: Chumphon, Ranong (Khao Chom Laem), Surat Thani, Phangnga, Nakhon Si Thammarat (Khao Luang), Trang (Ko Libong), Satun, Songkhla, Yala (Bannang Sata), Narathiwat.

Distribution : Nepal (type), NE India (Madras, Sikkim), Bhutan, S China (Yunnan, Hainan, Hong Kong), Taiwan, Myanmar, Laos, Vietnam, Malaysia (Peninsular, Sabah, Sarawak), the Philippines, Indonesia (Kalimantan, Sumatra, Java), Papua New Guinea (Admiralty Islands), Solomon Islands.

Ecology : Epiphytic or lithophytic in evergreen forests, mixed deciduous forests, open hill forests or lowland scrub, often beside streams. Also occurring in limestone forests, and sometimes growing directly on limestone rocks, 50–1,950 m alt. Often locally abundant. Flowering: (March–) April–October (–December).

Vernacular : Krasun phra in (กระสุนพระอินทร์)(Narathiwat).

Notes: This widespread species exhibits considerable variation in the length of its inflorescence and in the number and size of the flowers it bears. However, the fleshy, concave and externally keeled lateral sepals, which are distinct from the dorsal sepal, are diagnostic.