1	Branches on lower nodes of culms densely interwoven, with many, tough, sharp thorns		(2)
+	Branches on lower nodes of culms with tough and/or weak thorns but not densely interwoven		(6)
2 (1)	Culm sheaths pubescent only near base		(3)
+	Culm sheaths pubescent on basal half to entire sheath		(4)
3 (2)	Lower internodes of culms glabrous; culm sheath apically subtruncate; auricles subequal, usually reflexed.		3 B. sinospinosa
+	Lower internodes of culms with longitudinally arranged, stiff hairs; culm sheath apically broadly arched; auricles dissimilar, not reflexed.		4 B. funghomii
4 (2)	Lower nodes of culms usually with a ring of silky white hairs below and above sheath scar; culm sheaths densely stiffly hairy; auricles usually crescent-shaped, reflexed.		1 B. blumeana
+	Lower nodes of culms without silky hair rings or with only a ring of brown hairs below sheath scar		(5)
5 (4)	Culm sheath apically broadly concave, with a triangular protuberance on each shoulder; auricles tiny or absent, narrowly filiform if present.		2 B. flexuosa
+	Culm sheath apically broadly convex, without protuberance on each shoulder; auricles well developed, ovate-oblong to ovate-lanceolate.		4 B. funghomii
6 (1)	Culm sheath auricles large, to 2 cm wide		(7)
+	Culm sheath auricles small, less than 1 cm wide		(12)
7 (6)	Culm sheath blade width 2/3–3/4 width of sheath apex		(8)
+	Culm sheath blade width 2/5–3/5 width of sheath apex		(9)
8 (7)	Lowest internodes of culms usually with purple streaks; nodes with a ring of brown silky hairs below and above sheath scar; culm sheaths uniformly hairy, apex nearly truncate, ligule ca. 3 mm.		24 B. insularis
+	Lowest internodes without purple streaks; nodes with a ring of gray-white hairs below and above sheath scar; culm sheaths only hairy at central base, apex broadly convex, ligule ca. 7 mm.		25 B. xiashanensis
9 (7)	Lower culm internodes densely hairy; culm sheath apically subtruncate, larger auricles nearly 3 × size of smaller ones.		11 B. rutila
+	Lower culm internodes glabrous; culm sheath apically usually broadly convex, sometimes subtruncate, larger auricles to 2 × size of smaller ones		(10)
10 (9)	Basal culm internodes with pale green stripes; leaf blade abaxially glabrous.		12 B. lapidea
+	Basal culm internodes without stripes; leaf blade abaxially pubescent		(11)
11 (10)	Culm sheaths glabrous, ligule ca. 6 mm.		10 B. macrotis
+	Culm sheaths with dense, stiff, brown hairs, ligule ca. 2 mm.		13 B. latideltata
12 (6)	Culm sheath ligule 5–8 mm		(13)
+	Culm sheath ligule 0.5–3(–4) mm		(15)
13 (12)	Culm sheath apically obliquely truncate, with unequal, triangular protuberance on each shoulder and white stripes		5 B. chunii
+	Culm sheath apically obliquely asymmetrically arched, with neither protuberance on each shoulder, nor white stripes		(14)
14 (13)	Culm sheath auricles very unequal, usually wrinkled; basalmost culm internodes sometimes with pale yellow stripes.		8 B. dissimulator
+	Culm sheath auricles subequal; culm internodes with purple stripes initially.		15 B. longipalea
15 (12)	Culm sheath blade base more than 4/5 width of sheath apex		(16)
+	Culm sheath blade base less than 3/4 width of sheath apex		(23)
16 (15)	Culm sheaths hairy at least near base, rarely glabrous		(17)
+	Culm sheaths glabrous throughout		(19)
17 (16)	Lower culm nodes with a ring of stiff, pale brown hairs below and above sheath scar, basal ca. 3 nodes with a ring of gray-white silky hairs above sheath scar; culm sheaths with stiff, appressed, dark brown hairs.		23 B. diaoluoshanensis
+	Lower culm nodes with a ring of gray-white silky hairs below and above sheath scar; culm sheaths with hairs absent, pale, or restricted to base		(18)
18 (17)	Culm sheath apically slightly asymmetrically arched-convex, usually glabrous or with stiff, dark brown hairs near base.		14 B. indigena
+	Culm sheath apically ± truncate, distal half with deciduous, stiff, appressed, pale hairs.		16 B. cornigera
19 (16)	Culms both normal and abnormal, internodes of normal culms terete, lower internodes of abnormal culms greatly shortened and swollen; culm sheath ligule 0.5–1 mm.		21 B. ventricosa
+	Culms all normal, internodes terete; culm sheath ligule 3(–4) mm		(20)
20 (19)	Culm sheaths with 1 or 2 pale yellow stripes near outer margin, apex slightly asymmetrical, broadly triangular or broadly arched		(21)
+	Culm sheaths without stripes, apex subtruncate or obliquely truncate		(22)
21 (20)	Lower culm internodes hairy; leaf blade linear-lanceolate to lanceolate, 1.3–1.7 cm wide.		14 B. indigena
+	Lower culm internodes glabrous; leaf blade narrow, linear-lanceolate, 1–1.3 cm wide.		17 B. subaequalis
22 (20)	Basal nodes with a ring of gray-white silky hairs below and above sheath scar; culm sheath apically subtruncate, with a protuberance on one shoulder.		22 B. corniculata
+	Basal nodes with a ring of gray-white silky hairs below sheath scar only; culm sheath apically obliquely truncate, without protuberance on shoulders.		27 B. ramispinosa
23 (15)	Culm sheaths obliquely truncate, or obliquely truncate and convexly arched, or slightly asymmetrical and concavely arched		(24)
+	Culm sheaths symmetrical, apex convexly or triangularly arched, or asymmetrically triangular		(27)
24 (23)	Culm sheaths with a triangular protuberance on higher shoulder, blade not narrowed at base.		18 B. gibba
+	Culm sheaths without a protuberance on higher shoulder, blade basally narrowed and incurved		(25)
25 (24)	Culm sheaths hairy.		20 B. angustiaurita
+	Culm sheaths glabrous		(26)
26 (25)	Culms 3–7 m, 1.5–4 cm in diam., culm sheath ligule ca. 1 mm.		7 B. glabrovagina
+	Culms 8–10 m, 4–6 cm in diam., culm sheath ligule 3–4 mm.		19 B. malingensis
27 (23)	Culm sheaths with stiff, dark brown hairs only near base, apex symmetrical, ligule 3–4 mm; foliage leaf blade abaxially densely pubescent.		26 B. prominens
+	Culm sheaths glabrous or only hairy below blade, apex asymmetrically triangular; ligule 1–2 mm; foliage leaf blade abaxially sparsely villous or subglabrous		(28)
28 (27)	Basal culm nodes with rings of gray-white to pale brown silky hairs below and above sheath scars; culm sheaths hairy below blade; auricles long decurrent, ca. 3 mm wide; ligule finely dentate, fimbriate.		6 B. angustissima
+	Basal culm nodes glabrous; culm sheaths glabrous; auricles not decurrent, ca. 5 mm wide; ligule entire, very shortly ciliolate.		9 B. aurinuda