2.04  PSEUDOSASA Makino ex Nakai

Christopher M.A. Stapleton

Plants shrublike, spreading or loosely to densely clumped; rhizomes leptomorph. Culms 0.5–13 m tall, to 4 cm thick, self-supporting, erect or nodding, pluricespitose; nodes not or slightly swollen; supranodal ridge not evident; internodes mainly terete, only slightly flattened immediately above the branches, glabrous, with light wax below the nodes. Branches initially 1–3, erect to arcuate, often short, central branch dominant, with compressed basal nodes, branches fully sheathed, lateral branches arising either from the basal nodes or from more distal nodes, sheaths and prophylls more or less glabrous, persistent, tough. Culm leaves coriaceous and very persistent; blades erect or reflexed, narrowly triangular to strap-shaped. Foliage leaves: sheaths persistent; blades cross veined, medium to large for the size of the culm, without marginal necrosis in winter, their arrangement random. Inflorescences racemose or paniculate; branches subtended by much reduced or quite substantial bracts. Spikelets 2–20 cm, with 3–30 florets; rachillas sinuous; disarticulation below the florets. Glumes 2, shorter than the first lemma; lemmas to 1 cm; anthers 3; styles 3; paleas 2-keeled. Named for the similar, but 6-anthere genus Sasa, in which it had been included.

Pseudosasa includes about 36 species, all of which are native to Japan, China, and Korea.

1. Pseudosasa japonica (Siebold & Zucc. ex Steud.) Makino ex Nakai

Japanese Arrow Bamboo, Metake, Yadake

Culms 1–3(5) m tall, to 1.5 cm thick, erect or nodding, finely ridged; nodes slightly raised; sheath scar large; internodes long, finely mottled, with a light ring of wax below the nodes. Culm sheaths to 25 cm, basally glabrous, distally appressed-hispid, persistent; auricles and oral setae absent; blades 2–5 cm, erect, abaxial surfaces glabrous. Branches usually 1 per node, with no basal buds or branches, sometimes rebranching from more distal nodes. Foliage leaves: sheaths glabrous, edges membranous; auricles absent or small and erect; oral setae absent or scarce, erect; ligules long, oblique, erose, slightly pubescent, abaxial ligules glabrous to finely ciliate; blades 15–35 cm long, 1.5–5 cm wide, glabrous or abaxial surfaces sporadically shortly red-brown tomentose, light green to glaucous, adaxial surfaces dark green, glossy, glabrous. Spikelets 3.5–10 cm, narrowly cylindrical, curved, with 5–20(25) florets. Lemmas 1.2–1.5 cm, glabrous, often mucronate, mucros about 2 mm; paleas nearly equaling the lemmas, glabrous, keels finely cilate.

Pseudosasa japonica is a widely cultivated ornamental species that used to be cultivated for arrows in Japan. There are no known wild populations. It forms a tough and effective screen, and has become naturalized in British Columbia and the eastern United States. A shorter cultivar with partially ventricose culms, ‘Tsutsumiana’, and cultivars with variegated leaves are also available.