Bambusa sp. (TH: Chiang Mai)

Bambusa sp.


  • Specimens: BS-0347 [†] (living plant), from Ban Pho Thong Charoen, Doi Saket District, Chiang Mai Province, 11 Dec. 2009, cult., received as ไผ่รวกดำ (phai ruak dam), started flowering in late Dec. 2014 and died in mid-2016; BS-0234 [†] (living plant), 1 Aug. 2009, and BS-0396 (culm-leaf), 10 Jan. 2010, both from the same clump from Ban Pa Fang, Doi Saket District, Chiang Mai Province, cult., received as ไผ่รวกดำ (phai ruak dam), started flowering in Jan. 2017 and died in mid-2017.
  • Characters: Habit a tight erect clumper. Rhizome pachymorph, short-necked. Culms straight upright, basal and lower culm typically unbranched, height 20 m or little over, diameter 4 (5) cm. Young shoots dull dark green, shooting usually late July to September. Culm-internodes dull dark green, white mealy velvety on lower section, glabrous or nearly so on upper section [bright dark green in phai liang dam, bright mid green in phai liang wan], (30) 35 (40) cm long, thick-walled, solid or nearly so on lower culm (7th internode 88 cm above ground 4.0 cm in diameter with 1.2 cm thick wall). Culm-nodes not prominent, with a narrow white ring below sheath scar; branch buds as tall as broad, or slightly taller than broad [broader than tall in phai liang wan, much broader than tall in phai liang dam]. Branches many, central branch dominant, branching intravaginal. Culm-leaves on basal and lower culm either persistent and rotting on the culm (rotten sheath remnants may remain attached), or (late) deciduous [typically early deciduous in phai liang, typically persistent in Thyrsostachys siamensis]; culm-leaves of mid and upper culm deciduous; culm-leaves whitish when dry. Culm-leaf sheath sparsely covered with short white mealy velvety hairs; apex truncate, slightly convex-waved. Culm-leaf auricles small, oral hairs few, short, early deciduous. Culm-leaf ligule short, entire, eciliate. Culm-leaf blade broad-triangular, erect (typically not reflexed), persistent or late deciduous, glabrous. Foliage-leaves (5) 7–10 (13) per branchlet. Foliage-leaf sheath glabrous. Foliage-leaf auricles none; oral setae none. Foliage-leaf ligule inconspicuous. Foliage-leaf blades mid to dark green, small and narrow, (7) 11 (14) × (0.8) 1.0 (1.5) cm, glabrous on both surfaces; margins slightly antrorsely scabrous; petiole 1 mm long.
  • Uses: Culms for construction and tools; plants for hedges, screening and wind-break.
  • Cultivation requirements: Easy-growing; in part shade to full sun, sandy loam to clay loam, moisture-retentive, can resist some drought.
  • Provisional identification:
    (1) This species remains unidentified so far. At first sight, it was assumed to be Thyrsostachys oliveri. In general appearance, this bamboo (BS-0347, BS-0234) is the bamboo with the closest similarity to Thyrsostachys siamensis, but culm-leaves are different. However, the culm-leaves of the plants do not match closely with Gamble's original description and line drawing of culm-leaves of T. oliveri (J. S. Gamble, Bambuseae Brit. India, 1896: p. 58–59 [#1230]). There is also some similarity with the unidentified phai liang (provisionally named Bambusa nana hort.), and with Dendrocalamus strictus. The plants (BS-0347, BS-0234) are certainly neither conspecific with phai liang, nor with D. strictus. The plants (BS-0347, BS-0234) can be clearly distinguished from both common phai liang plants, phai liang dam and phai liang wan. Though there are several plants from different sources labeled as Dendrocalamus strictus being grown at Baan Sammi, their identity is not confirmed, hence the plants (BS-0347, BS-0234) cannot currently compared with Dendrocalamus strictus.
    (2) Since BS-0347 flowered, and somewhat later BS-0234, it became clear that this species belongs to the Bambusa-Dendrocalamus-Gigantochloa complex, and is neither conspecific with phai liang, nor with Dendrocalamus strictus. It was assumed that the plants (BS-0347, BS-0234) are closely related to Thyrsostachys oliveri. However, flowers have not yet investigated in detail to verify its identity. As for vegetative parts, a main unresolved obstacle is the difference of culm-leaf characters between the description (and line drawing) by Gamble, and the observed characters in the plants (BS-0347, BS-0234). Could it be that the material on which Gamble based his description was a mixture from different plants? The line drawing and description of the culm-leaf in Gamble's publication matches very well with phai liang.
  • Flowering and seeding: Neither seeds in the flowers, nor seedlings on the ground were found; Compilation of Bamboo Seeds: BS-0347, BS-0234. This indicates a possible hybrid origin, and one of the parents could be Thyrsostachys.
  • Specimens: BS-0927 [-] (herbarium material), from Samoeng District, Chiang Mai Province, coll. by ธ. บ., s.n., Feb. 2018, received 23 Feb. 2018.
  • Comments: (1) Neither seeds were found in the flowers nor seedlings on the ground of the flowering mother plant. (2) Possibly the same species as BS-0234, BS-0347.