Volume 12 > Part 1 > Year 2011 > Page 44 > Orchidaceae > Cryptostylis

Cryptostylis arachnites (Blume) Hassk.

Cat. Hort. Bot. Bog.: 48. 1844; Hook.f., Fl. Brit. India 6: 118. 1890; Seidenf. & Smitinand, Orchids Thail.: 53, 728, fig. 540. 1959–1965; Seidenf., Dansk Bot. Ark. 32(2): 106, fig. 66. 1978; J.B.Comber, Orchids Java:49. 1990; Seidenf., Opera Bot. 114: 26. 1992; Seidenf. & J.J.Wood, Orchids Penins. Malays. Singap.: 49, fig. 14a–d, t. la. 1992; J.B.Comber, Orchids Sumatra: 87. 2001; Thaithong, Thai Orchids [in Thai]: 56. 2000; Sitthisajjadham, Wild Orchids Thail. [in Thai]: 178. 2006; S.C.Chen et al. in Z.Y. Wu et al. (eds), Fl. China 25: 89. 2009.— Zosterostylis arachnites Blume, Bijdr.: 419. 1825. [For additional synonyms, see Seidenfaden, Dansk Bot. Ark. 32(2): 106. 1978]. Fig. 22.

Accepted Name : This is currently accepted.

Description : Flowering shoots 24–52.5 cm tall; stem 1–4 mm in diameter. Foliage leaves 1–3; petiole channelled, 3.3–12.5 cm long, spotted with purple; lamina ovate to elliptic or broadly lanceolate, often oblique, acuminate, (6.8–18.4–16 by (2.6–)4–6.7 cm. Inflorescence cylindric, 9- to many flowered; rachis (5.5–)12–30 cm long; bracts ovate-lanceolate, long-acuminate, shorter than or subequal to the ovary, 7–18 by 2–6.2 mm. Flowers short-pedicelled, predominantly dull brownish-red (sepals and petals light green, labellum with dark crimson spots). Sepals subsimilar, linear-triangular, acuminate, glabrous, 3-veined, 14–16.7 by 2.3–2.9 mm. Petals spreading, linear-triangular, acuminate, 1-veined, 8–11.1 by 1.5–1.6 mm, with entire, inrolled margins. Labellum ovate-oblong, 13.9–20 by 5–8.3 mm; distal part flat with an acute to acuminate, distinctly incurved apex. Column semiterete, 2–3 mm long; anther 2.5–2.6 mm long, 1.4–1.5 mm wide, with a recurved, subacuminate apex. Ovary 7.5–17 mm long. Capsule short-pedicelled, ellipsoid, 10–15 mm long, 5–7 mm in diameter.

Thailand : NORTH-EASTERN: Loei; EASTERN: Nakhon Ratchasima (Khao Yai); PENINSULAR: Ranong (Khao Phota Luang Kaeo), Surat Thani (Ko Pha-ngan), Nakhon Si Thammarat (Khao Luang), Songkhla (San Kala Khiri), Yala (Betong), Narathiwat (Hala-Bala).

Distribution : Usually reported as widespread in Indomalesia and the West Pacific, from Sri Lanka and Assam in the west to Taiwan in the north-east and Samoa in the south-east. However, future taxonomic work on the Cryptostylis arachnites complex might well lead to a different view of the distribution of C. arachnites s.s.

Ecology : Terrestrial in hill evergreen forests, seasonal evergreen forests and upper tropical rain forests; 725–1,800 m alt. Flowering: recorded in February–August and November December.

Vernacular : Ueang maeng mum (เอื้องแมงมุม)(Loei); ueang din malaeng po (เอื้องดินแมลงปอ).

Notes: Sitthisajjadham (2006) reported Cryptostylis conspicua J.J.Sm. from Thailand, accompanied by a colour photo taken by H. Boonneuang in Hala-Bala Wildlife Sanctuary (Narathiwat). Cryptostylis conspicua was described when Smith (1921) divided the Javanese material of Cryptostylis into five species, including three that he described as new. Although C. conspicua is now widely accepted, species delimitation in the complex is still in need of further study. The photo published by Sitthisajjadham does suggest C. conspicua due to the absence of labellum markings. However, due to the problematic nature of the complex and because no voucher was collected in Narathiwat that would allow for floral measurements to be taken (S. Sitthisajjadham, in litt. to K. Srimuang), C. conspicua is not formally recognized for Thailand in the present treatment. Nevertheless, continued search for this species in Narathiwat and elsewhere in Peninsular Thailand might well prove fruitful - for which reason C. conspicua is included in the key above.