Pteris biaurita 

Pteris biaurita L.

Family     :  Pteridaceae

Terrestrial fern, 1-1.5 m tall. Rhizome erect, woody, closely invested with stipe bases and densely clothed at apex with small triangular-ovate scales, these 1.5-3 mm long, bicolorous with glossy black, triangular-attenuate midrib and broad, pale, delicately clathrate, lacerate-ciliate margins. Fronds densely clustered, suberect, 0.6-1.5 m long; stipes stout, to 5 mm diam., strawcolored, grooved adaxially, naked except for a few bicolorous scales at base. Blades oblong or triangular-oblong, to 40 cm broad, 1-pinnate-pinnatisect, the basal pinnae forked; rachis glabrate and naked except for minute glandular papillae in the upper surface groove at axils of pinnae; pinnae 5-15 pairs, opposite, sessile or nearly so, all but the basal 2-partite ones, narrowly oblong lanceolate to lanceolate-attenuate, broader on the basiscopic side; segments mostly 15-22 pairs, narrowly oblong to linear, 1-3 x 0.3-0.5 cm, joined by a costal wing 2-3 mm broad on either side, the fertile ones separated by round sinuses; veins prominulous, the basal ones joined by a narrow costal arc with several excurrent simple branches, the others free, usually once-forked; tissue thin herbaceous, light green, somewhat translucent. Indusium pale, 0.3-0.5 mm wide, with entire margin.