朗木铁角蕨 lang mu tie jiao jue

Plants 5-8 cm tall. Rhizome erect, short, apex scaly; scales dark brown, narrowly triangular, subentire to denticulate. Fronds caespitose; stipe 1.5-3.5 cm, slender, adaxially sulcate, base dark brown and with scales, upward green, with fibrillar scales; lamina narrowly triangular, 4-5 × 1.4-1.8 cm, base slightly reduced, apex acute-acuminate with triangular apical segment ca. 12 × 6 mm, 2-pinnate at base; pinnae 5 or 6 pairs, opposite to subopposite, shortly stalked, basal pinnae slightly reduced, middle pinnae trapeziform-elliptic, 6-9 × 4-9 mm, base nearly symmetrical, truncate to cuneate, 1-pinnate at base or simple, apex obtuse; basal pinnae with up to 2 pinnule pairs, basal acroscopic pinnules largest and free, 3-4 × 2-2.5 mm, base broadly cuneate, apex serrate with long and sharp teeth, apex obtuse. Veins slightly raised adaxially, 2-forked or simple, not reaching margin. Fronds firmly herbaceous, green, brown-green when dry; rachis green, adaxially sulcate, lamina subglabrous, average guard cell length 45-52 µm. Sori 1-3 per segment, median on subtending vein, confluent at maturity, linear, 2-3 mm; indusia white-gray, semi-elliptic, membranous, entire, opening toward costa or costule, persistent. Spores with lophate (costate) perispore, average exospore length 33-36 µm.

● Juniperus forests; 3300-3600 m. S Gansu, NW Sichuan.

Asplenium neovarians, known from few collections, needs more study. Based on the length of its stomata and exospore, it should at least be tetraploid. It is similar to A. altajense (but different in its more distinct apical pinna), A. aitchisonii (but different in its putative ploidy level), and A. kukkonenii, and from all of which it differs in perispore morphology.