7. Bambusa glabrovagina G. A. Fu, Acta Phytotax. Sin. 20: 489. 1982 [“glabro-vagina”].
光鞘石竹 guang qiao shi zhu
Culms 3–7 m, 1.5–4 cm in diam.; internodes 21–27 cm, initially thinly white powdery, glabrous; wall thick; branching to base. Branches 3 to several at each node, clustered, central 3 dominant; branchlets at lower nodes sometimes forming tough, curved thorns. Culm sheaths deciduous, glabrous, apex slightly inclined to outer side and asymmetrical, broadly convex or subtruncate; auricles unequal, linear-lanceolate or oblong, less than 3 mm wide, margin with curved setae; ligule ca. 1 mm, margin irregular, finely dentate; blade erect, ovate to ovate-lanceolate, base ca. 3/5 width of sheath apex, abaxially glabrous, adaxially slightly scabrid near base, apex acuminate. Leaf blade linear-lanceolate to lanceolate, 5–12 × 0.8–1.7 cm, abaxially densely pubescent, adaxially glabrous. Pseudospikelets several, clustered at each node, linear-lanceolate to lanceolate, 1.5–2 cm; prophylls ovate, 3–3.5 mm, 2-keeled; gemmiferous bracts 2 or 3, ovate-elliptic to ovate-oblong, 3–3.5 mm, apex obtuse to acute, very shortly mucronate; florets 6 or 7, middle 3 or 4 perfect; rachilla segments flat, 2–3 mm, apex inflated and cupular. Glumes absent; lemma ovate-oblong, 7.5–8 mm, glabrous, 9–11-veined, apex acute, mucronate; palea linear-lanceolate, slightly longer than lemma, 4-veined between and 2-veined on either side of keels, apex with a cluster of white hairs; lodicules 3, unequal; anterior oblique, ca. 2 mm, margins long ciliate; posterior subobovate, ca. 1.2 mm. Filaments slender; anthers ca. 4 mm. Ovary ovoid, ca. 0.4 mm, base with stalk ca. 1 mm, apex thickened and hispidulous; style ca. 0.2 mm; stigmas 3, ca. 0.8 mm. Mature caryopsis unknown.
* Low hills, around villages. Hainan (Dunchang).