Volume 6 > Part 4 > Year 1998 > Page 424 > Cyperaceae > Tricostularia

Tricostularia undulata (Thwaites) J.Kernwfo-0000592991

Act. Bot. Néerl. 8: 267, 1959; Reinwardtia 6: 69. 1961; in Fl. Males., Ser. 1, Spermat. 7: 672, f. 78. 1974; Hô, Câyco Viêtnam III. 2: 669. 1993.— Cladium undulatus Thwaites, Enum. Pl. Zeyl. 353. 1864; C.B.Clarke in Fl. Br. Ind. 6: 674. 1894; Ill. Cyp. t. 83, f. 6–11. 1909; Camus in Fl. Gén. I.-C. 7: 152. f. 19, 2–8. 1912; Ridl., Fl. Malay Penins. 5: 167. 1925; Kük. in Fedde, Repert. Sp. Nov. 51: 162. 1942. Fig. 39: A–G.

Accepted Name : Anthelepis undulata (Thwaites) R.L.Barrett, K.L.Wilson & J.J.Bruhl
Austral. Syst. Bot. 32: 284. 2019.

Description : Perennial. Culms densely tufted, 30–90 cm by 1–2 mm, trigonous, smooth, glabrous. Leaves basal; blade rather rigid, linear, 1–3 mm, subobtuse, deeply channelled, margins inrolled; sheath up to 5 cm long, brown or reddish brown. Involucral bracts several, leaf-like, the lowest 5–15 cm long. Inflorescence open to dense, 10–20 by 3–4 cm with (3–)4–5 nodes each subtending 2–3 partial inflorescences. Spikelets inclusters of 2–8, lanceolate, 4–5 by 1–1.5 mm, 4-glumed, 1-flowered. Glumes ovate to oblong-lanceolate, 2–5 by ca 1 mm, acute, sides membranous, several-veined, reddish brown. Perianth segments (3–)6, 0.3–0.5 mm long, densely hispidulous. Stamens 2–3; anthers 2 mm long. Nutlets elliptic to ovate-elliptic, trigonous to subterete 1.3–1.5 by 0.6–0.8 mm, blackish brown, rugose-reticulate.

Thailand : EASTERN: Ubon Ratchathani; SOUTH-EASTERN: Trat; PENINSULAR: Surat Thani, Nakhon Si Thammarat, Satun, Pattani.

Distribution : From Sri Lanka (type) through Indochina and Malesia east to N Australia.

Ecology : Sandy soil on heath, open forests or wet sandstone outcrops, 0–1,500 m alt.

Notes: Lepidosperma chinensis Nees & Mey, is also found in open sandy habitats characteristic to Tricostularia undulata. Since it has been recorded from south-eastern China and Malesia it may also occur in Thailand. It can easily be recognised by the terete, unifacial leaves and small panicles subtended by a spathe-like involucral bract.