Melocalamus scandens

Type: China, Yunnan: Jiangcheng, Mantan, alt. 1,100 m, 1 Apr. 1988, Zhao Jian-Wei & Hui Chao-Mao 88027, holotype (SWFC); cf. J. X. Liu & al., Plant Diversity, July 2022 [#1372].

Chinese name: 大吊竹 (dà diào zhú).

Distribution: CHINA (South): southern Yunnan, in broad-leaved montane forests at 700–1,000 m altitude.

Descriptions:

(1) "Culms to 20 m, 2–4 cm in diam.; internodes 45–50 cm; wall ca. 5 mm thick; nodes flat, each with a brown tomentose ring above and below. Branches several, dominant ones to 6 m. Culm sheaths brown, asymmetrical, leathery, initially minutely powdery, apex oblique; auricles asymmetrical, with some oral setae; ligule ca. 1 mm, entire; blade erect, triangular, base about as wide as sheath apex. Leaf sheaths glabrous; auricles minute; ligule ca. 1 mm; blade lanceolate, 15–25 × 1.5–2.5 cm. Inflorescence unknown." — Flora of China, accessed 29 August 2022 [#1303].

(2) "Perennial; caespitose. Rhizomes short; pachymorph. Culms scandent; 2000 cm long; 20-40 mm diam.; woody. Culm-internodes terete; thin-walled; 45-50 cm long. Culm-nodes flush with internodes; pubescent. Lateral branches dendroid. Branch complement several. Culm-sheaths coriaceous; brown; auriculate; with unequal auricles; setose on shoulders. Culm-sheath ligule 1 mm high; entire. Culm-sheath blade triangular; as wide as sheath at base; erect. Leaf-sheaths glabrous on surface. Leaf-sheath auricles absent. Ligule an eciliate membrane; 1 mm long. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate; 15-25 cm long; 15-25 mm wide. Leaf-blade venation with obscure cross veins. … Flowering specimens unknown." — KewScience POWO, accessed 29 August 2022 [#1305].

Images: Line drawings in Flora of China [#1303]. Photos in J. X. Liu & al., The identity of Dinochloa species and enumeration of Melocalamus (Poaceae: Bambusoideae) in China, Plant Diversity, July 2022: fig. 3 and 12 [#1372].

Specimens: BS-0006 [-] (living plant), received at Bambusetum Baan Sammi from China as "澜沧梨藤竹 (lan cang li teng zhu) Melocalamus arrectus", 21 July 2011; BS-0724 [-] (living plant), received as "梨藤竹 (lí téng zhú) Melocalamus compactiflorus", 23 Nov. 2011.

Characteristics:

(1) Habit caespitose, not of a very tight clump. Rhizome pachymorph, to about 40 cm long, perhaps with a somewhat elongated neck [n.v.]. Culms: Longer than 10 m by 3.5 cm in diameter [ultimate size not known, May 2021], not straight; lower culms more or less upright, or ascending, upper culms leaning into nearby vegetation and scrambling; the basal and lower culms usually unbranched. Young shoots green, conical, appear in March/April. Culm-internodes terete, mid-green when young, lower quarter of internode length glabrous, upper 3/4 covered with short white fuzz when young, minutely scabrous when old, 50-60 (68) cm long; diameter somewhat larger at breast height than at the base (e.g., 1.9 cm on the basal culm, 2.3 cm on the lower culm 2 m above the ground), hollow, basally almost solid, walls 0.8 cm thick with a culm diameter of 2.6 cm at 1.0 m height above the ground, walls 0.5 cm thick with a culm diameter of 2.7 cm at 2.6 m height, walls 0.4 cm with a diameter of 2.8 cm at 3.8 m height, walls 0.4 cm with a diameter of 3.5 cm at 4.3 m height [wall thickness on the upper culm not seen]. Culm-nodes slightly prominent, glabrous; with a 7 mm tall corky girdle-like sheath scar; with a white ring below and above the node. Branch-buds solitary, large, ovate to subrotund; the three lowest nodes usually without a bud. Branches thin, many, subequal, arising in 4 tufts around the bud margin, each tuft with about 7–12 slender branches, the central part of the bud usually remains dormant, but occasionally develops a much dominant and very long central branch, with a diameter as thick, or nearly as thick, as the main culm, the slender branches short, 0.4-0.7 m long; the dominant branch rebranching, the slender branches usually not rebranching; branching infravaginal. Culm-leaves early deciduous, light green when young, white when dry, becoming straw-colored when old, asymmetric, shorter than the internode. Culm-leaf sheath leathery, brittle, covered with short white fuzz when young, almost glabrous when old, margins eciliate, smooth, apex oblique. Culm-leaf auricles small but conspicuous, protruding, rounded to sickle-shaped, with short bent white bristles. Culm-leaf ligule very low, entire or subentire, eciliate, with rudimentary cilia towards the edges. Culm-leaf blade erect, broad triangular with the basal edges rounded, persistent to the sheath, as long as the sheath (shorter on the lower culm, longer on the upper culm), light green, with a reddish tint towards the apex when young. Foliage-leaves (10) 12 (13) per branchlet. Foliage-leaf sheaths glabrous. Foliage-leaf auricles large, projecting, sickle-shaped, with a few long white bristles. Foliage-leaf ligule inconspicuous. Foliage-leaf blades 12 (18) x 2 (3) cm, asymmetric, glabrous on both surfaces, base rounded to cuneate, apex attenuate; margins antrorsely scabrous; midrib slightly prominent; pseudopetiole very short, ca. 0.5–1 mm long.

(2) Culm size: Diameter increasing with height, gradually increasing from the base to the lower mid-culm up to 30% (e.g., BS-0006: basal diameter 2.3 cm, diameter 3.0 cm on the 6th internode at 2.1 m above the ground; BS-0724: basal diameter 3.1 cm, diameter 3.5 cm on the 10th internode at 2.5 m above the ground), then remaining constant for several meters and gradually decreasing towards the top. A culm diameter that increases with the culm height between the base and the lower mid-culm has also been observed in some other species (e.g., in genus Dendrocalamus, Gigantochloa, Melocalamus, Schizostachyum) under cultivation at Bambusetum Baan Sammi: BS-0078, BS-0208, BS-0494, BS-0550, BS-0602. The diameter differences can be seen with the naked eye, but are not as impressive as in BS-0550.

Comments:

(1) The plants received, BS-0006 and BS-0724, are conspecific. However, they neither represent Melocalamus arrectus, nor Melocalamus compactiflorus, and do not meet the characteristics of other Melocalamus species described in the Flora of China [#1303], except Melocalamus scandens, which seems to be closest to the two specimens.

(2) The species, as represented by BS-0006 (young plant) and BS-0724 (nearly mature plant), can be easily distinguished from Melocalamus arrectus by its asymmetric and auriculate culm-leaves, its eciliate culm-leaf ligule, and foliage-leaf sheaths with large, projecting bristly auricles.

(3) Although the specimens are similar to Melocalamus scandens, they mainly differ by having somewhat prominent and glabrous culm-nodes, culm-leaves with somewhat larger auricles, rounded lower edges of the oblique triangular culm-leaf blade, the presence of large, projecting bristly foliage-leaf auricles, and somewhat smaller foliage-leaf blades with very short pseudopetioles.

(4) Applying the key in J. X. Liu & al., l.c., 2022, accessed 29 August 2022 [#1372], the two specimens are clearly identified as Melocalamus scandens.