Dendrocalamus longispathus

Synonym: Bambusa longispatha Kurz, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 42 (4), 1874: 250.

Thai names: ไผ่ลำมะลอก (phai lam malok) (Central); ไผ่หกดำ (phai hok dam) (Northern); ญะ (ya) (Northern); บงป่า (bong pa) (Northern); ไม้ซางไผ่ (mai sang phai) (Udon Thani). — T. Smitinand, 2001 [#1003]; BKF [#1368].

English name: Long Sheath Bamboo.

Distribution: THAILAND. — MALAYSIA (Peninsular): north-eastern part. — MYANMAR. — BANGLADESH. — INDIA (North-East).

Culm size: Height 10–20 m, diameter 7–10 (13) cm.

Descriptions:

(1) "A large tufted bamboo. Culms usually 10-18 m high, glaucous green when young, grayish‌-green on maturity; nodes slightly swollen, often rooting; internodes 25-60 cm long, 6-10 cm diameter, covered by long papery remnants of sheaths and dark-brown pubescence, walls ca. 1.2 cm thick. Culm-sheaths 35-50 cm long and 10-20 cm broad, inner surface glabrous and outer surface clothed densely with patches of stiff dark-brown hair; margin light straw-coloured in the upper half; ligule broad, much serrate or often long fimbriate; auricles usually absent, sometimes very small on one side; blade 25-40 cm long and 2.5-3.5 cm broad, lanceolate-acuminate, recurved. Young shoots spear-shaped. Leaves 10-30 cm long and 2.5-4.5 cm broad, oblong-lanceolate to linear-lanceolate, acuminate, short-stalked margins rough; leaf-sheath ligulate, covered with brown pubescence, margin ciliate. …" — K. K. Seethalakshmi & al., Bamboos of India, 1998: p. 114 [#1062].

(2) "Culm sheaths pale green, densely covered with appressed pale and silver hairs; blade broadly lanceolate and very long, as long as or longer than the sheath proper, spreading to reflexed; auricles spreading lobes 4–5 mm high, bristly on margin and inner side, bristles 1–4 mm long; ligule 3–4.5 mm high, the base 2.5–4 mm high, divided into fine teeth or short bristles 1–3 mm long. Culms to 12–20 m tall, commonly 8–12 cm diameter; internodes 40–50 cm long, dark green, not white-waxy, with scattered appressed pale-silvery hairs all over, with a band of silvery brown hairs below and above each node. Leaf: blades 12–35 cm long, 2.5–6 cm wide, glabrous except for scattered short hairs near the base on lower side; stalk 3–6 mm long; auricles crisped rims 0.5–1 mm high, glabrous or occasionally with scattered bristles on margin, bristles 2–3 mm long; ligule a subentire rim 0.5–1.5 mm high, the margin with very fine short hairs." — K. M. Wong, Bamboos of Peninsular Malaysia, 1995: p. 115 [#1210].

(3) "Rhizomes short; pachymorph. Culms erect; 1000–1800 cm long; 60–100 mm diam.; woody; without nodal roots, or with aerial roots from the nodes. Culm-internodes terete; thick-walled; 25–60 cm long; glaucous, or grey; distally pubescent. Lateral branches dendroid. Buds or branches absent from lower quarter of culm. Culm-sheaths persistent; 35–50 cm long; 2–3 times as long as wide; chartaceous; hispid; with dark brown hairs; concave at apex; without auricles. Culm-sheath ligule dentate, or fimbriate. Culm-sheath blade lanceolate; reflexed; 25–40 cm long; 25–35 mm wide; pubescent; acuminate. Leaf-sheaths pubescent; hairs dark brown; outer margin hairy. Leaf-sheath auricles absent, or falcate. Ligule a ciliolate membrane. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate; 10–30 cm long; 25–45 mm wide. Leaf-blade midrib conspicuous. Leaf-blade venation with 16–20 secondary veins. Leaf-blade surface scabrous; rough abaxially; glabrous. Leaf-blade margins scabrous. Leaf-blade apex acuminate. …" — Kew GrassBase [#1335].

(4) "Habit: Perennial; caespitose. Rhizomes short; pachymorph. Culms erect; 1000-1800 cm long; 60-100 mm diam.; woody; without nodal roots, or with aerial roots from the nodes. Culm-internodes terete; thick-walled; 25-60 cm long; glaucous, or grey; distally pubescent. Lateral branches dendroid. Buds or branches absent from lower quarter of culm. Culm-sheaths persistent; 35-50 cm long; 2-3 times as long as wide; chartaceous; hispid; with dark brown hairs; concave at apex; without auricles. Culm-sheath ligule dentate, or fimbriate. Culm-sheath blade lanceolate; reflexed; 25-40 cm long; 25-35 mm wide; pubescent; acuminate. Leaf-sheaths pubescent; hairs dark brown; outer margin hairy. Leaf-sheath auricles absent, or falcate. Ligule a ciliolate membrane. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate; 10-30 cm long; 25-45 mm wide. Leaf-blade midrib conspicuous. Leaf-blade venation with 16-20 secondary veins. Leaf-blade surface scabrous; rough abaxially; glabrous. Leaf-blade margins scabrous. Leaf-blade apex acuminate. … [flowers and seeds described]." — KewScience POWO, accessed 19 July 2020 [#1305].

Images: Line drawing in J. S. Gamble, Bambuseae Brit. India, 1896: pl. 78 [#1230]; K. K. Seethalakshmi & al., Bamboos of India, 1998: fig. 32, p. 116 [#1062]. Photos in Bamboos of India, 1998, l.c. (habit, culms, shoots, flowers) [#1062]; BambooTech (culm sheath, culms); TNAU Agritech (culms); BoldSystems (culm-leaf); M. Kumar, 2009: p. 28 (habit, culms, culm-leaves, young shoot, flowering branches) [#1188].

Uses: Shoots palatable; culms for construction, roofing, furniture, basketry, mat making, fences, rafts, paper pulp.

Comments:

(1) Flowering cycle: 30–32 years; seed viability about 2 months [#1302]. The production of seeds can be very low and the seeds sterile [#1330].

(2) Internodes scattered with short-appressed whitish hairs when young. The species is similar in appearance to Dendrocalamus hamiltonii, but culm-leaf sheaths are distinguishable, e.g., the apex of Dendrocalamus longispathus is concavely depressed.

(3) The Thai name, ไผ่บงป่า (phai bong pa), was found cited for this species, but phai bong pa is a species of Bambusa, similar to the species named in Thai phai bong, but with culms somewhat bending or flexuous, not straight, and with branches from the basal culm up, forming a thicket. The culm-leaf of phai bong pa is substantially different. A plant of phai bong pa [HHK-003] at the Royal Project, Huai Hong Khrai (ห้วยฮ่องไคร้) Study Center, A. Doi Saket, Chiang Mai Province, was mislabeled "Bambusa longispatha Gamble". It is actually a species of Bambusa, perhaps Bambusa burmanica.

(4) ไผ่ลำมะลอก (phai lam malok), another species grown at Huai Hong Khrai [HHK-014, actually Bambusa longispiculata], was mislabeled "Dendrocalamus longispathus Kurz", and later the label changed to "Arundinaria suberecta". Phai lam malok has an open, diffuse culm growth habit, and culm sheaths are also substantially different from Dendrocalamus longispathus.