2.02 BAMBUSA Schreb.
Christopher M.A. Stapleton
Plants usually arborescent, in well defined or rather loose clumps; rhizomes pachymorphic, with short necks. Culms 0.5–30(35) m tall, 0.5–18(20) cm thick, woody, perennial, usually self-supporting; nodes not swollen; supranodal ridges obscure; internodes terete, usually thinly covered initially with light-colored wax. Branch complements usually with a dominant primary central branch and 2 smaller co-dominant lateral branches, usually similar at all nodes; bud scales 2-keeled, thickened, initially closed at the back and front; branches all subtended by bracts, higher order branchlets at the lower nodes sometimes thornlike. Culm leaves usually promptly deciduous, initially lightly waxy, sometimes with short, stiff hairs, subsequently losing the wax and becoming glabrous; auricles usually well developed; fimbriae usually present; blades triangular to broadly triangular, usually erect. Foliage leaves: sheaths usually deciduous from the lower nodes of the branches, persistent at the distal nodes; blades to 30 cm long, to 6 cm wide, not distinctly cross veined. Inflorescences usually spicate, rarely capitate, bracteate; prophylls 2-keeled, narrow. Pseudospikelets 1–5 cm, with 3–12 florets; disarticulation above the glumes and below the florets, rapid; rachilla internodes usually long. Glumes several, subtending the buds; lemmas narrowly ovate, acute, unawned; paleas not exceeding the lemmas, 2-keeled, not winged; anthers 6; ovaries usually suboblong; styles short, with (2)3–4 plumose branches. 2n = 56–72. Name a Latinized form of bambu, a local name of Malayan origin.
Bambusa is a tropical and subtropical genus of 75–100+ species. It is native to southern and southeastern Asia, but is widely cultivated and naturalized throughout the tropics. Bambusa vulgaris and B. multiplex grow widely in Florida and Texas, having spread to some extent after being planted as ornamentals. Other species are known only in cultivation. The American Bamboo Society lists over 40 species as being commercially available in North America in 2005. This treatment includes a few of the more commonly cultivated species.
SELECTED REFERENCES But, P.P.-H., L.-C. Chia, H.-L.F., and S.-Y. Hu. 1985. Hong Kong Bamboos. Urban Council, Hong Kong. 85 pp.; Dransfield, S. and E.A. Widjaja (eds.). 1995. Plant Resources of South-East Asia [PROSEA] No. 7: Bamboos. Backhuys, Leiden, The Netherlands. 189 pp.; Edelman, D.K., T.R. Soderstrom, and G.F. Deitzer. 1985. Bamboo introduction and research in Puerto Rico. J. Amer. Bamboo Soc. 6: 43–57; McClure, F.A. 1955. Bambusa Schreb. Fieldiana, Bot. 242: 52–60; Pohl, R.W. 1994. Bambusa Schreber. Pp. 193–194 in G. Davidse, M. Sousa S., and A.O. Chater (eds.). Flora Mesoamericana, vol. 6: Alismataceae a Cyperaceae. Universidad Nacional Autónoma de México, Instituto de Biología, México, D.F., México. 543 pp.; Soderstrom, T.R. and R.P. Ellis. 1988. The woody bamboos (Poaceae: Bambuseae) of Sri Lanka: A morphological–anatomical study. Smithsonian Contr. Bot. 72:1–75; Stapleton, C.M.A. 1994. The bamboos of Nepal and Bhutan, Part I: Bambusa, Dendrocalamus, Melocanna, Cephalostachyum, Teinostachyum, and Pseudostachyum (Gramineae: Poaceae, Bambusoideae). Edinburgh J. Bot. 51:1–32; Stapleton, C.M.A. 2002. Bambusa ventricosa versus Bambusa tuldoides. Bamboo 23:17–18; Widjaja, E.A. 1997. New taxa in Indonesian bamboos. Reinwardtia 11:57–152; Wong, K.M. 1995. The Morphology, Anatomy, Biology, and Classification of Peninsular Malayan Bamboos. University of Malaya Botanical Monographs No. 1. University of Malaya, Kuala Lumpur, Malaysia. 189 pp.; Xia, N.H. and C.M.A. Stapleton. 1997. Typification of Bambusa bambos (Gramineae, Bambusoideae). Kew Bull. 52:693–698.
For an interactive dichotomous key, click here; the interactive, multientry key is not yet available.
1. Branchlets of the lower branches recurved, hardened, thornlike ... B. bambos
1. Branchlets of the lower branches not thornlike ... 2
2. Culm sheath auricles well developed, to 5 cm long ... B. vulgaris
2. Culm sheath auricles absent or poorly developed ... 3
3. Culm internodes antrorsely hispid; culms 0.5–7 m tall, broadly arched above ... B. multiplex
3. Culm internodes glabrous; culms 6–15 m tall, erect ... B. oldhamii
1. Bambusa bambos (L.) Voss
Giant Thorny Bamboo
Plants densely clumped, with intertwined thorny branches. Culms to 20(35) m tall, 12–18 cm thick, thick-walled, sometimes almost solid; internodes 20–40 cm, green, waxy at first, becoming dull. Branches forming at the basal and upper nodes, central branches slightly dominant, branchlets of the lower branches recurved, hardened and thornlike. Culm leaves dark green, initially sparsely hairy, sometimes more densely hairy on the margins and auricles, hairs dark brown, deciduous; auricles subequal, wrinkled, wide; fimbriae absent; ligules to 2 mm, ciliate; blades erect or reflexed, merging into the auricles, adaxial surfaces densely brown-velvety. Foliage leaves: sheaths glabrous; ligules short, entire; auricles small; fimbriae few, erect; blades 6–22 cm long, 1–3 cm wide, glabrous. Inflorescences initially spicate, becoming dense globular clusters. Pseudospikelets 10–30 mm, with 3–7 florets. Lemmas 7–8 mm, glabrous; anthers to 5 mm. 2n = 70–72.
Bambusa bambos is native to India and Indochina, but is cultivated throughout the tropics. It was the first bamboo species to be given a scientific name, being described as treelike, thorny, and a source of tabashir, lumps of pure silica that form in the internodal cavities. Bambusa arundinacea (Retz.) Willd. is a synonym of B. bambos that still appears in some listings of bamboos.
2. Bambusa vulgaris Schrad. ex J.C. Wendl.
Plants forming moderately loose clumps, without thorny branches. Culms 10–20 m tall, 4–10 cm thick, erect, sinuous or slightly flexuous; nodes slightly inflated, flaring at the pubescent sheath scar; internodes 20–45 cm, glossy green, yellow, yellow with green stripes, or green with yellowish green stripes, all similar or the basal internodes swollen and shorter than those above. Branches developing from the midculm nodes and above, occasionally also at the lower nodes, several to many branches per node, branchlets of the lower branches not thornlike. Culm leaves promptly deciduous, with dense, appressed, brown pubescence, lower sheaths broader than long, apices broader than the base of the blades; auricles well developed, to 5 cm long and 1.5 cm wide, equal, ovoid to falcate-spreading, dark; fimbriae to 15 mm, dense, wavy, light; blades 4–5 cm long, 5–6 cm wide, appressed to the culm, usually persistent, triangular, abaxial surfaces glabrous, adaxial surfaces densely dark pubescent towards the base, basal margins ciliate or with stiff hairs; ligules about 3 mm, shortly ciliate. Foliage leaves: sheaths glabrous to sparsely hispidulous; ligules 0.5–1.5 mm, glabrous, truncate, entire; auricles 0.5–1.5 mm, falcate, hardened, persistent; fimbriae few, 0.5–1.5 mm, spreading; blades 6–30 cm long, 1–4 cm wide, glabrous, abruptly acuminate. Pseudospikelets 12–35 mm, with 5–10 florets, always strongly grooved along the center, appearing 2-cleft. 2n = 64.
Bambusa vulgaris probably originated in tropical Asia. It is now the most widely cultivated tropical bamboo, largely because of the ease with which the branches and culm sections take root. Many different cultivars exist, including forms with variously green and yellow-striped culms which are sometimes placed in distinct varieties or even species. ‘Wamin’ is a cultivated form with ventricose to very short, concertina-like internodes. Like B. tuldoides ‘Buddha’s-Belly’, plants of B. vulgaris ‘Wamin’ can develop abbreviated internodes when grown in pots or under extreme environmental conditions; they readily return to normal growth when these conditions are ameliorated.
3. Bambusa multiplex (Lour.) Raeusch. ex Schult. & Schult. f.
Plants densely clumping, without thorny branches. Culms 0.5–7 m tall, 1–2.5 cm thick, emerging at an angle, broadly arching above, usually thin-walled and hollow, solid in some cultivars; nodes not swollen; internodes all similar, 3–60 cm. Branches to 20 per node, erect to spreading, the central branch slightly dominant, often becoming densely congested and forming tangled clusters of rhizomes, aborted shoots, and stunted roots, branchlets of the lower branches not thornlike. Culm leaves 12–15 cm, narrowly triangular, tardily deciduous, initially light green, becoming reddish brown to stramineous, glabrous; auricles and fimbriae developed; blades 1–2 cm, initially appressed to the culm, initially antrorsely hispid on both surfaces, becoming glabrous. Foliage leaves: sheaths glabrous; ligules to 0.5 mm; auricles absent; fimbriae sometimes present; blades 7–15 cm long, 1–2 cm wide, abaxial surfaces glaucous and slightly pubescent, adaxial surfaces dark green and glabrous. Pseudospikelets 30–40 mm, with up to 10 florets. 2n = 72.
Bambusa multiplex is native to southeast Asia. It is now widely planted around the world. The dense foliage with many leaves on each branchlet makes it well suited to hedging. A large number of cultivars are available, some with striped culms and leaves, others with greatly reduced stature and leaf size suitable for bonsai culture or hedging. The tangled branch clusters allow natural dispersal and easy propagation in hot, humid climates. Plants listed as B. glaucescens (Willd.) Sieb. ex Munro in North America probably belong to B. multiplex.
4. Bambusa oldhamii Munro
Plants forming dense to moderately loose clumps, without thorny branches. Culms 6–15 m tall, 3–13 cm thick, erect; internodes all similar, hollow, walls about 1 cm thick, pale green, glabrous, glaucous below the nodes. Branches very short, not thorny, the central branch at each node often tardily developed, branches not developing from the lower nodes, branchlets of the lower branches not thornlike. Culm leaves promptly deciduous, oblong, initially brown-sericeous, becoming glabrous, rounded distally; auricles absent or very small and rounded; fimbriae few, to 3 mm, curved; ligules to 2 mm, entire or finely serrulate; blades broadly subtriangular, usually with concave margins, abaxial surfaces glabrous, adaxial surfaces antrorsely hispid, apices acuminate. Foliage leaves: sheaths striate, glabrous or sparsely hispidulous, margins very shortly ciliate; auricles very small, rounded; fimbriae many, to 5 mm, fine, wavy; ligules to 1 mm, truncate, glabrous, entire; blades 15–30 cm long, 3–6 cm wide, oblong-lanceolate, abruptly acuminate, abaxial surfaces pubescent initially, becoming glabrous, adaxial surfaces glabrous. Pseudospikelets with 6–10 florets. 2n = unknown.
Bambusa oldhamii is native to low-lying areas of eastern China and Taiwan. It is the most commonly grown large, clump-forming bamboo in the United States, where it is grown mostly in Florida and California. With its upright culms and short branches it makes an excellent tall hedge.