西畴柳叶耳蕨 xi chou liu ye er jue

Cyrtogonellum xichouense S. K. Wu & Mitsuta, Acta Phytotax. Geobot. 36: 25. 1985.

Plants evergreen. Rhizome erect or ascending; scales dense, fuscous brown, lanceolate, margins entire, apices filiform. Fronds 60-70 cm; stipe stramineous, 25-30 cm, ca. 3 mm in diam. at middle; basal stipe scales dense, fuscous brown, subulate-lanceolate, membranous, slightly toothed, caudate; distal stipe scales sparser and smaller. Lamina 1-pinnate, green or light green when dry, adaxially slightly shiny, lanceolate, up to 35 × 6 cm at middle, not or only basalmost pinnae slightly contracted, apex pinnatifid-acuminate; rachis stramineous, without proliferous bulbils, sparsely scaly; scales similar to distal stipe scales, lanceolate or linear, margins slightly toothed, apices filiform. Pinnae up to 30 pairs, alternate, angled slightly acroscopically, lower pairs attached at nearly right angles with rachis, shortly stalked, obliquely deltoid-falcate, middle pairs ca. 3 × 1 cm, bases asymmetrical, acroscopic bases auriculate, apices acute and ascendant; auricles rounded, proximal margins of auricles slightly overlapping rachis, acroscopic margins repand or obtuse-toothed, basal basiscopic margins cuneate, forming a 50°-70° angle with rachis, entire, distal basiscopic margins curved upward, repand or with 6-8 obtuse teeth; adaxially glabrous, abaxially sparsely scaly; microscales light brown, linear; frond texture papery; venation pinnate on pinnae, lateral veins 2- or 3-forked, distinct abaxially, indistinct adaxially. Sori in 1 row on each side of midrib, terminal on shorter veinlets, medial, whole lamina fertile; indusia present, brown, entire.

● Limestone crevices or cliffs in forests; ca. 1700 m. SE Yunnan (Xichou).

Polystichum xichouense is an apomict producing 32 spores per sporangium.