70. Pteris biaurita Linnaeus, Sp. Pl. 2: 1076. 1753.
狭眼凤尾蕨 xia yan feng wei jue
Campteria biaurita (Linnaeus) Hooker; Pteris flavicaulis Hayata.
Plants 70-110 cm tall. Rhizome erect, robust, 2-2.5 cm in diam., woody, apex densely clothed with brown scales. Fronds clustered; stipe light brown, apically straw-colored to pale green, slightly lustrous, 40-60 cm, 3-5 mm in diam., glabrous, scaly, rarely with a few scales, adaxially narrowly grooved; rachis straw-colored, glabrous, narrowly grooved adaxially; lamina 2- or 3-pinnatipartite, oblong-ovate in outline, 40-55 × 20-30 cm; lateral pinnae 8-10 pairs, decumbent, opposite, lower ones shortly stalked, 3-5 cm apart; upper ones sessile, broadly lanceolate, 15-20 × 3-5.5 cm, base broadly cuneate, pectinately divided to broadly winged costa (to 8 mm wide), apex narrowly lanceolate and caudate (2-3 cm); basal pair of pinnae often each with 1 or sometimes 2 basiscopic pinnules similar to main part of pinna but smaller; segments 20-25 pairs, alternate, subspreading, sinuses obtuse-rounded, 2-5 mm apart, falcate, broadly lanceolate to falcate-oblong, 18-35 × 5-7 mm, base slightly enlarged, margins entire, apex slightly narrow and obtuse; terminal pinna similar to middle lateral pinnae, stalked (ca. 1.5 cm); costae prominent abaxially, straw-colored, glabrous, slightly grooved adaxially, with short spines on both sides; veins slightly raised, conspicuous on both surfaces, acroscopic veinlet of lobe base and a basiscopic veinlet of upper lobe base combining to form an arcuate vein, anastomosing to form a series of narrow areoles along costules, with 5 or 6 free veinlets extending to margin at arcuate vein, and a majority of veinlets outward from areole usually 2-forked; lamina gray-green, thickly papery when dried, glabrous. Indusia light brown, membranous, entire, persistent.
Dry sloping fields; 200-1500 m. Guangdong, Guangxi (Baise), Guizhou, Hainan, C and S Taiwan, Xizang, Yunnan [Bangladesh, Bhutan, India, Indonesia, Laos, Malaysia, Nepal, Philippines, Sri Lanka, Thailand; pantropical].
Fraser-Jenkins (Taxon. Revis. Indian Subcontinental Pteridophytes, 115-116. 2008) recognized two subspecies, both apomictic, for Asian material: Pteris biaurita subsp. walkeriana Fraser-Jenkins & Rajkumar (loc. cit.: 115) for a diploid plant, type from Sri Lanka and also recorded from Bangladesh, Bhutan, India, Indonesia, Myanmar, Nepal, Philippines, and Thailand and including Xizang and S and SW China, and P. biaurita subsp. fornicata Fraser-Jenkins (loc. cit.: 116), a more common and widespread triploid plant, also with a type from Sri Lanka and recorded from Bangladesh, Bhutan, India, Indonesia, Malaysia, Nepal, and Thailand and including Taiwan, Xizang, and S and SW China. The latter has more regularly arcuate veins, slightly deeper connections between the pinna segment, and a more papery lamina.