Bambusa contracta L.C. Chia & H.L. Fung (1981:376)

Qin, Qiao-Mei, Cai, Zhuo-Yu, Ni, Jing-Bo, Tong, Yi-Hua & Xia, Nian-He, 2022, The floral morphology of four Chinese Bambusa species (Poaceae, Bambusoideae) previously described only from vegetative material, PhytoKeys 213, pp. 143-159 : 143

Bambusa contracta L.C. Chia & H.L. Fung (1981:376)

Figs 1 , 2

Holotype.

China, Guangdong Province: Guangzhou City, cultivated in South China Botanical Garden, Chinese Academy of Sciences (plants originally from Guangxi, Dongxing), 15 August 1978, Nan-Zhu 2061 (IBSC!).

Epitype (designated here).

China, Guangdong Province: Guangzhou City, cultivated in South China Botanical Garden, Chinese Academy of Sciences, 31 March 2016, Qin & Ni QQM 39 (IBSC!).

Description including flowering material.

Culms 5-6 m tall, 2-3 cm diameter, erect, apically drooping; internodes 34-57 cm long, plain green, initially slightly white waxy, with sparse long white hairs; wall ca. 3 mm thick; nodes flat, glabrous. Branch complement at mid-culm with a slightly dominant central branch and many subequal branches, those at culm base without thorny branchlets. Culm leaf sheath slightly white waxy, usually glabrous or basally dark brown hispid, apically arched with asymmetric sides; auricles unequal, oblong to lanceolate, undulate, wrinkled, larger auricle slightly slanted downwards, ca. 3 cm long, 0.7-1 cm wide, ca. 2 times larger than smaller one, bristles on the margin undulate; ligule ca. 2 mm high, margin sparsely dentate; blade erect, narrowly ovate, ca. 2/5 as long as sheath, base rounded, slightly overlapping with auricles for 2-3 mm, ca. 1/4 as wide as sheath apex, apex involute and acuminate. Foliage leaf sheath glabrous; auricles subovate, margin with long bristles; ligule very low, margin sparsely dentate; blade linear to linear-lanceolate, 10-15 cm long, 1.3-1.5 cm wide, abaxial surface densely pubescent, adaxial surface glabrous. Pseudospikelets fasciculate at each node of flowering branches, linear, sessile, basally subtended by several bud-bearing bracts, 2.5-3.5 cm long; florets 4-6, middle 2-4 florets fully developed; prophylls 1-2 mm long, 2-keeled, keels sparsely ciliolate; bracts 2-4, ovate to oblong, 3-5 mm long, glabrous, apically ciliolate, adaxial surface apex puberulent, obscurely 0-5-veined, apex obtuse to acute, mucronate or not; rachilla disarticulating between florets, segments compressed, 1.5-3 mm long, glabrous, lower segments distally inflated, upper segments distally only slightly inflated; glumes 1-3, oblong, 6-7 mm long, glabrous, sometimes adaxial surface apex puberulent, obscurely 11-13-veined, apex obtuse to acute, mucronate or not; lemma oblong, 7-10 mm long, glabrous, abaxial surface purple-spotted, 19-21-veined, apex acute mucronate, calluses no more than 5 mm long, glabrous; palea 9-11 mm long, 2-keeled, keels apically ciliolate, 4-5-veined between keels, each side 2-veined, apex truncate; lodicules 3, apex ciliate, anterior two broadly oblong, 2-3 mm long, posterior one narrowly oblong, 2-3 mm long; stamens 6, filaments filiform, anthers brown to yellowish, 5.5-7 mm long, apex retuse; ovary obovoid, 1.8-2 mm long, apex hispidulous, styles 3, 0.5-0.7 mm long, stigmas 3, plumose, 4-5 mm long.

Note.

We made a comparison between this species and its relative, Bambusa textilis McClure. The result shows that they share similar floral characters. B. contracta differs from B. textilis in having 4-5 veins between palea keels (versus 10), 2 veins on each wing of the palea (versus 4) and 11-13 veins on the glumes (versus 21).

Figures

Figure 1. Vegetative morphology and pseudospikelets of B. contracta A clumps B clump base C culm internode D branch complement E culm node with velvety hairs F pseudospikelets G culm leaf (abaxial view) H culm leaf (adaxial view) I the distal part of a leafy branch (upper side) J the distal part of a leafy branch (lower side).

Figure 2. Floral morphology of B. contracta A pseudospikelet B prophyll (abaxial view) C rachilla segment D bud-bearing bract (adaxial view) E axillary bud subtended by bract in (D) F, G glumes (adaxial view) H lemma showing margins I palea showing margins J back of palea K lodicules L pistil M stamen. Drawn by Qiao-Mei Qin.