Gigantochloa hasskarliana

Synonym: Schizostachyum hasskarlianum Kurz, Indian Forester, 1, 1876: 352.

Type: Java, Kurz, s.n. (L, lectotype; cf. Widjaja, 1987: 335).

Thai names: ไผ่ผากมัน (phai phak man) (Peninsular); ไผ่ผาก (phai phak) (Peninsular). — T. Smitinand, 2001 [#1003]; BKF [#1368].

Indonesian name: bambu lengka tali.

Distribution: THAILAND (South): Nakhon Si Thammarat Province: Khao Luang [National Park], "common in evergreen forest" at 600 m altitude (Kew Herbarium [#1333]); (North-East and Central): "Klang Dong" (กลางดง) District [Khao Yai National Park], in "evergreen forest" (Kew Herbarium [#1333]); cf. comments below. — MYANMAR: probably native. — MALAYSIA: cultivated. — INDONESIA: Sumatra, Java, Kalimantan, native, wild, and cultivated, usually in lowlands, occasionally up to 1,500 m altitude in wet tropics, prefers humid conditions. — N. Bystriakova & al., Bamboo Biodiversity, 2003: map 34 [#1342].

Culm size: Height 8–12 m, diameter 3–6 cm.

Descriptions:

(1) "Densely tufted, sympodial bamboo. Culms up to 10 m tall, 3–6 cm in diameter, wall 8–10 mm thick; internodes up to 51 cm long, green, when young covered with dark brown hairs in upper parts, glabrous later. Culm sheath triangular, 10–27 cm long, rather late deciduous, covered with appressed blackish-brown hairs; blade lanceolate with narrow base and acute apex, 2–14 cm × 5–15 mm, usually deflexed but sometimes erect at base of culm; ligule up to 3 mm long, irregularly toothed, ending in fine hairs; auricles firm, rim-like, up to 3 mm long, the ends usually somewhat raised, glabrous, edge of culm sheath extends beyond auricles. Young shoots very slender, grey-green with dark brown hairs appressed on the back of sheaths, sheath blades initially erect, becoming spreading to deflexed. Leaf blade lanceolate, 8–35 cm × 1–5 cm, glabrous on lower surface; leaf sheath with dark brown hairs along the margin; ligule to 2 mm long, toothed, each tooth ending in a fine hair; auricles small, rounded, up to 1 mm long and 1 mm in lateral extent, glabrous. … [flowers and seeds described]." — E. A. Widjaja in S. Dransfield & E. A. Widjaja (eds.), Plant Resources of South-East Asia No. 7, Bamboos, 1995: p. 107–109, fig. [#1226].

(2) E. A. Widjaja, Revis. Malesian Gigantochloa, 1987: p. 335-339, fig. 16-17 [#1224].

(3) "Culm sheaths pale green, densely covered with dark brown hairs; blade broadly lanceolate, erect but becoming spreading to reflexed; auricles low rims 1–2 mm high, glabrous; ligule a low slightly toothed rim 1.5–2 mm high, not bristly. Culms to 5–6 m tall, commonly 4–5 cm diameter; internodes 30–40 cm long, dark green, without white wax, glabrous or with scattered dark hairs near the top of the internode, with a narrow band of short pale brown hairs below and above each node. Leaf: blades 10–25 cm long, 1–3.5 cm wide, glabrous; stalk 1.5–3 mm long; auricles small lobes 1–2 mm high, glabrous; ligule a finely toothed or ciliate rim 0.5–1.5 mm high … [flowers described]." — K. M. Wong, Bamboos of Peninsular Malaysia, 1995: p. 126, fig. 65 [#1210].

(4) "Culms up to 6 m. tall by 5 cm. thick, green, with dark hairs below the nodes when young; culm-sheaths dark-hairy on the back, black-fringed on the margins when young; blade spreading or deflexed, hairy above, narrowed at the base; auricles low, stiff, dark green, entire, usually raised and rounded at the ends; ligule up to 4 mm. high, toothed, the teeth bristly when young; leaf-blades up to 40 x 4.5 cm., glabrous, stalks up to 5 mm. long; auricles small; ligule short entire or toothed. … [flowers and seeds described]." — H. B. Gilliland & al., Revised Flora of Malaya, vol. 3, 1971: p. 35 [#1039].

(5) "… caespitose. Rhizomes short; pachymorph. Culms erect; 500–600 cm long; 30–50 mm diam.; woody. Culm-internodes terete; hollow; mid-green; distally pubescent. Lateral branches dendroid. Buds or branches absent from lower quarter of culm. Culm-sheaths hairy on margins; auriculate. Culm-sheath ligule 2–4 mm high; ciliolate. Culm-sheath blade lanceolate; narrower than sheath; spreading, or reflexed; pubescent. Leaf-sheath oral hairs lacking. Leaf-sheath auricles falcate. Ligule an eciliate membrane; entire, or erose. Collar with external ligule. Leaf-blade base with a brief petiole-like connection to sheath; petiole 0.2–0.5 cm long. Leaf-blades lanceolate; 15–40 cm long; 20–45 mm wide. Leaf-blade surface glabrous … [flowers and seeds described]." — Kew GrassBase [#1335].

Uses: Culms can be used for basketry; plants for hedges, and for the prevention of soil erosion.

Comments:

(1) The species was originally described from Java.

(2) "The bamboo which is identified as G. hasskarliana in Thailand and is found growing abundantly in pure stands in the northern and western parts of the country, is not conspecific with G. hasskarliana. The culm sheath of the Thai bamboo has a large, broadly triangular, usually erect blade. Its correct name, unfortunately, is not yet confirmed." (E. A. Widjaja, l. c., 1995: p. 108).

(3) The records from Thailand (based on Kew Herbarium [#1333]) are from wild habitats in southern and central Thailand. Whether these specimens are true Gigantochloa hasskarliana or other species remains unknown.

(4) The specimens cited below (BS-0299, BS-0543, BS-0542, BS-0543A) have lanceolate (not broad-triangular) culm-leaf blades, and almost all their other characteristics match very well with those of Gigantochloa hasskarliana as described by E. A. Widjaja (l. c., 1995).

(5) BS-0602, listed under Gigantochloa sp., might be conspecific with BS-0299, BS-0543, BS-0542, BS-0543A.

Specimens: BS-0543 [C3] (living plant), = CS-3045, herb. spec.: SING, and BS-0542 [BBG] (living plant), = CS-3044, both เขาพระ (Khao Phra), Songkhla Province ["Kha Phra, Satun", in err.], southern Thailand, both collected by C. S., received 30 May 2010. BS-0543A [C7] (living plant: seedling), raised from seeds of BS-0543 in March 2015: a low quantity of seeds in two grades (BS-0543A, BS-0543B) collected by D. O., Feb. – Mar. 2015, from a single flowering plant.

Characteristics (BS-0543):

(1) Habit tight caespitose, erect. Rhizome pachymorph, short [n.v.]. Culms straight [ultimate size not recorded, expected to attain a height of about 10 m]. Young shoots light green, with black hairs, apical sheath blades many, long and erect; shooting June – July. Culm-internodes 25–27 cm long (by diameter 1.5 cm), dull brownish green or yellowish straw-colored when old, glabrous on the lower and mid-section, slightly rough on the upper section; moderately thick-walled. Culm-nodes not prominent, or slightly prominent on thin culms with the nodal ridge line clearly visible. Branches many, subequal; branching extravaginal or intravaginal. Culm-leaves persistent or late deciduous, light straw-colored when dry. Culm-leaf sheath about half the length of the internode, light green, or pinkish to yellowish green when young, covered with short black hairs throughout, the hairs more or less deciduous with age; margins black-ciliate; apex somewhat rounded. Culm-leaf auricles rim-like, firm, raised and rounded towards the ends, bright mid-green when young, deepening to dark-green with age, glabrous; without oral setae. Culm-leaf ligule short, entire, eciliate(?). Culm-leaf blade erect, linear-lanceolate to lanceolate, mid-green when young, light straw-colored and twisted when dry, caducous. Foliage-leaves (5) 6 (8) per branchlet. Foliage-leaf sheaths glabrous, orange when young. Foliage-leaf auricles rounded, glabrous; without oral setae. Foliage-leaf ligule entire, eciliate. Foliage-leaf blades 20–25 × (1.6) 1.9 (2.2) cm, linear-lanceolate, mid-green, glabrous on both surfaces; base cuneate; margins antrorsely scabrous; pseudopetiole 1–2 (3) mm long. Flowering branches leafless, or terminating leafy branches. Pseudo­spikelets few (3–5) in a cluster, clusters bracteate, 1–5 (8.5) cm apart, 1–2 pseudospikelets per cluster much dominant, linear, sometimes slightly bent, 2–3 cm long, 4 mm wide, laterally compressed, dull dark purplish, margins of bracts dark ciliate, pseudo­spikelets dis­articulating as a whole. Florets/flowers [not investigated in detail]; anthers 6, dark purplish, 5–9 mm long, apex mucronate; filaments united in a white tube; stigma single, white, plumose, conical(?).

(2) Wall thickness was measured in the 4th internode (lower culm) of two culms only with the following two diameters: Ø 2.2 cm, wall width 0.4 cm; Ø 1.3 cm, wall width 0.4 cm.

Cultivation requirements: Easy growing, grows well in full sun or partial shade, soil normal moisture-retentive or moist with good drainage.

Seed weight: 2 g ≈ 45–52 grade A seeds (dried spikelets: husk-wrapped seeds).

Seed viability: Unknown, viability is assumed to last at least several months.

Seed germination: A germination rate of 30–40% can be expected from grade A seeds (test 150301).

Comments:

(1) The identity of this Gigantochloa species has not yet been confirmed. Characteristics indicate that it could be Gigantochloa hasskarliana or a closely related species.

(2) BS-0543 began to flower sporadically in early March 2014, continued its vegetative growth, began to flower gregariously by the end of December 2014, with peak flowering in March and April 2015, continued vegetative growth by developing new leaves in late April 2015, and developed new shoots in late June 2016. Since then, the plant has been growing further (28 Oct. 2018).