泰国毛蕨 tai guo mao jue

Thelypteris siamensis Tagawa & K. Iwatsuki, Acta Phytotax. Geobot. 22: 101. 1967; Christella siamensis (Tagawa & K. Iwatsuki) Holttum.

Plants 70-100 cm tall. Rhizomes erect, apices along with stipe bases with dense linear-lanceolate brown scales. Fronds clustered; stipes 20-40 cm, stramineous, subglabrous or with sparse pale long acicular hairs distally; laminae 50-70 × 30-40 cm, bases not narrowed or slightly so, apices acuminate; lateral pinnae 25-35 pairs, middle ones linear-lanceolate, 10-20 × 1.5-2 cm, bases broadly cuneate or truncate, sessile, lobed 2/3-4/5 toward costae, apices long acuminate; segments 20-30 pairs on middle pinnae, oblong, 5-8 × ca. 3 mm, obtuse at apices, basal acroscopic ones usually longer and crenate; veinlets 6-12 pairs, proximal pair anastomosing or sometimes only connivent, distal veins ending before margin and above sinus. Laminae herbaceous, yellowish green when dried, with pale long acicular hairs along rachises, costae, and veins on both surfaces. Sori orbicular, medial; indusia with dense pale acicular hairs. Sporangia bearing golden glands on stalks. Spores echinate or tuberculate.

Wet places in forests; 1300-1400 m. ?Taiwan, S Yunnan (Jinping) [?NE India, Thailand].

The character of veinlets not reaching the margin is unique in this species of Cyclosorus but also occurs in Metathelypteris. The connivent veinlets resemble those of Pseudocyclosorus. The systematic position of this species requires more study.