疏羽半边旗 shu yu ban bian qi

Pteris semipinnata Linnaeus var. dissitifolia (Baker) C. Christensen & Tardieu.

Plants 1-1.5 m tall. Rhizome ascending or erect, 1-1.5 cm in diam., apex and stipes basally densely clothed with scales; scales median brownish black, light brown to gray at margins, without luster, linear-lanceolate, ca. 2 mm in diam., subentire, apex long acuminate. Fronds clustered; stipe castaneous-brown, adaxially sorrel-red, sometimes nearly brownish, shiny, 40-80 cm × 4-5 mm, glabrous, adaxially grooved; rachises castaneous-brown; lamina 2-pinnatipartite on both sides or either side, ovate-oblong in outline, 35-50 × 25-30 cm; lateral pinnae 5-8 pairs, opposite or subopposite, basal pairs 6-8 cm apart, stalked (1-3 mm), upper sessile, decumbent, pinnae oblong-lanceolate, 15-25 × 4-6 cm, base oblique, apex tapering; basal 1 or 2 pairs of pinnae often pinnatipartite on both sides; basal pair of pinnae often with a pinnule near base on basiscopic side; median pinnae often pinnatipartite on basiscopic side, entire on acroscopic side or only pinnatipartite on upper parts; upper pinnae pinnatipartite on basiscopic side, entire on acroscopic side; segments lanceolate, 4-12 × 1-1.3 cm, gradually shorter upward, acuminate; basal segments on basiscopic side longest, basally decrescent to a broad wing, sterile margins slightly serrate; terminal pinna pinnatipartite, divided nearly to costa, triangular-ovate in outline, ca. 15 × 10-12 cm, base broadly cuneate, somewhat decurrent, apex acuminate; segments 8-10 pairs, alternate or subopposite, ca. 1 cm apart, decumbent, falcate-lanceolate, 6-8 × 0.6-0.8 cm, gradually shorter upward, base conspicuously decrescent, with interrupted broad wing along costules, apex mucronate; costae prominent abaxially, straw-colored at apex, castaneous-brown downward, adaxially grooved, grooves with thin raised pale gray edges (minutely and irregularly toothed); veins conspicuous on both sides, sparse, decumbent, often 1- or 2-forked; lamina pale green, firmly herbaceous when dried, glabrous.

Sparse shaded forests; 100-300 m. Guangdong, Hainan (Baoting), S Yunnan (Hekou, Xishuangbanna) [Laos, N Vietnam].

Lu and Yang (Taiwania 50: 137-165. 2005) reported Pteris dissitifolia as a new species for Taiwan, but Knapp (Ferns Fern Allies Taiwan, 478. 2011) noted that there is no apparent delimitation between this and P. semipinnata in Taiwan.