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.
Clumps rather open. Culms 8-15 m, 5-9 cm in diam., basally straight or flexuose, apically drooping; internodes deep green, 20-30 cm, initially thinly white powdery, stiffly pale brown strigose; wall slightly thick; nodes slightly prominent, basal several with aerial roots and rings of grayish white silky hairs below and above sheath scar; usually branching from lower nodes. Branches several to many, clustered, central dominant. Culm sheaths deciduous, ribbed-striate when dry, densely stiffly deciduously dark brown hairy, apex arched below blade, concave below auricles; auricles conspicuous, ascending, nearly equal in shape and size, oblong or reniform, 8-10 mm; oral setae curved, fine; ligule 3-4 mm, serrate, very shortly white ciliolate; blade deciduous, erect or deflexed, broadly triangular to triangular, base slightly rounded, ca. 1/2 width of sheath apex, abaxially sparsely stiffly dull brown hairy, adaxially densely stiffly dull brown hairy between veins, apex involute, sharply apiculate. Leaf blade narrowly lanceolate, 10-30 × 1.3-2.5 cm, both surfaces glabrous. Pseudospikelets several, clustered at nodes, narrowly lanceolate to linear-lanceolate, slightly flattened, 2-3.5 × 0.4-0.5 mm, apparently bifid; gemmiferous bracts several; florets 5-10; rachilla segments 1.5-3 mm. Glumes 1 or 2, abaxially shortly hairy near apex, apex apiculate; lemma 8-10 mm, abaxially shortly hairy near apex, apex apiculate; palea slightly shorter than lemma, keels ciliolate; lodicules 3, 2-2.5 mm, margins long ciliate. Anthers ca. 6 mm, apex penicillate. Style 3-7 mm, slender; stigmas 3, short.