狭叶铁角蕨 xia ye tie jiao jue

Asplenium annamense Christ; A. pinfaense Christ.

Plants 20-45(-60) cm tall. Rhizome shortly creeping to erect, apex densely scaly; scales medium to dark brown, ovate-triangular, subentire to denticulate. Fronds simple, ± clustered, subsessile or with stramineous stipe 1-5(-)7 cm; lamina linear to narrowly lanceolate, 15-40(-50) × 1.1-2(-3) cm, usually more than 13 × longer than wide, gradually attenuate at both ends, base narrowly cuneate and decurrent on stipe, margin entire to repand or sinuate, with minute notches, apex long acuminate. Midrib (rachis) distinct, often slightly raised (semiterete) abaxially or adaxially; veins distinct, usually forked in their upper part. Fronds leathery, brownish green to olivaceous when dry, with sparse minute brown triangular-stellate scales. Sori linear, 4-7 mm, starting close to midrib at an angle of (40°-)50°-70°(-80°); indusium gray to yellowish brown, linear, relatively thick, entire, opening toward midrib, persistent. Spores with alate perispore.

On tree trunks or shaded wet rocks in forests; 1300-1600 m. Guangdong, Guangxi, Guizhou, Hainan, Yunnan [India, Malaysia, Myanmar, Thailand, Vietnam].

Typical Asplenium scortechinii plants have narrow fronds, but intermediates with A. griffithianum exist. Plants from the Malay Peninsula were found to be tetraploid (n = ca. 72) by Manton (in Holttum, Revis. Fl. Malaya 2: 625. 1954), but our recent FCM results show that, at least in China, this taxon is an aggregate of hexaploid (Hainan) and dodecaploid (Yunnan) species. In particular, the relationships with dodecaploid A. griffithianum needs further investigation.