Dendrocalamus hamiltonii
Dendrocalamus hamiltonii Nees & Arn. ex Munro, Trans. Linn. Soc. London 26 (1), 1868: 151.
Synonym: Sinocalamus hamiltonii (Nees & Arn. ex Munro) T. Q. Nguyen, Bot. Zhurn. (Moscow & Leningrad) 74 (11), 1989: 1662.
Thai names: ไผ่หก (phai hok) (Phetchabun); ไผ่นวลใหญ่ (phai nuan yai) (Kanchanaburi); ไผ่เผี่ยว (phai phiao) (Northern); ไผ่หกหวาน (phai hok wan), ไผ่หกนวลใหญ่ (phai hok nuan yai). — T. Smitinand, 2001 [#1003]; BKF [#1368].
Chinese names: 版纳甜龙竹 (bǎn nà tián lóng zhú), for Dendrocalamus hamiltonii; 巴氏龙竹 (bā shì lóng zhú), for Dendrocalamus parishii.
Distribution: THAILAND, possibly native [might have been confused with Dendrocalamus brandisii]. — BHUTAN. — NEPAL. — INDIA (North, North-East). — MYANMAR: "By far the commonest Himalayan Dendrocalamus species is D. hamiltonii. This species is apparently found along the entire Himalayan range, where it grows in gullies in subtropical forest types, especially along the outer ranges of hills … It is also found further into the foothills where it is quite widely planted." (C. M. A. Stapleton, Bamboos Nepal Bhutan I, 1994: p. 21). — CHINA (South): Yunnan: plants recorded as Dendrocalamus hamiltonii from China (image) are now considered misidentified and to represent true Dendrocalamus parishii (Y. B. Guo & N. H. Xia, in J. Top. Subtrop. Bot., 2010). — Also recorded from LAOS.
Culm size: Height 10–23 m, diameter 10–18 cm.
Descriptions:
(1) "… caespitose. Rhizomes short; pachymorph. Culms erect, or arching; 1200–2000 cm long; 100–185 mm diam.; woody; with root dots on the nodes. Culm-internodes terete; with small lumen; 30–50 cm long; dark green, or grey; distally pubescent. Lateral branches dendroid. Buds or branches absent from lower quarter of culm. Culm-sheaths 35–45 cm long; 2 times as long as wide; antrorsely scabrous; glabrous, or hispid; with dark brown hairs; truncate at apex. Culm-sheath ligule entire. Culm-sheath blade lanceolate, or narrowly ovate; narrower than sheath; 15–30 cm long. Leaf-sheaths keeled; hispid; hairs white. Ligule an eciliate membrane. Leaf-blade base asymmetrical; with a brief petiole-like connection to sheath. Leaf-blades lanceolate; 20–37 cm long; 20–40 mm wide. Leaf-blade venation with 12–34 secondary veins. Leaf-blade surface scabrous; rough abaxially; glabrous. Leaf-blade margins scabrous. Leaf-blade apex acuminate … [flowers and seeds described]." — Kew GrassBase [#1335].
(2) J. S. Gamble, Bambuseae Brit. India, 1896: p. 84 [#1230].
(3) K. K. Seethalakshmi & al., Bamboos of India, 1998: p. 109 [#1062]. — The shape of the culm sheath of the line drawing (fig. 30, p. 109) looks more like Dendrocalamus parishii than Dendrocalamus hamiltonii.
Images: Line drawing in J. S. Gamble, Bambuseae Brit. India, 1896: pl. 74. Photos in AsianFlora (leaves) [#1332]; S. J. Pei & al., 1998: fig. 8 (culms, culm sheath) [#1107]; BoldSystems (culm-leaf).
Characteristics (based on Kew GrassBase [#1335] and C. M. A. Stapleton, 1994): Rhizome pachymorph, short-necked; culms erect or arching, without branches on lower culm; culm internodes 30–50 cm long, pubescent when young, dark green, gray when old, thick-walled; culm sheaths rough, glabrous or with rigid dark brown hairs; culm sheath auricles small, triangular; culm sheath ligule entire; foliage leaf blades large, 20–37 cm long, 2–4 cm wide, rough, glabrous; leaf sheaths with stiff whitish hairs. — Dendrocalamus hamiltonii var. hamiltonii: Culm internodes up to 9 cm in diameter, not basally swollen; culm sheath blades slightly undulating. — Dendrocalamus hamiltonii var. undulatus: Culms erect to drooping, not pendulous, maximum height 23 m, culm internodes irregularly shaped, up to 15 cm in diameter, often basally swollen, shorter; culm sheath blades strongly undulating. — Dendrocalamus hamiltonii var. edulis: Culms more pendulous.
Uses: Dendrocalamus hamiltonii var. undulatus: Culms are used for making pillars and containers, and not for weaving; leaves for fodder. — Dendrocalamus hamiltonii var. edulis: Best suitable for the production of edible shoots.
Flowering and seeding: Flowering of ไผ่หก (phai hok), presumably Dendrocalamus hamiltonii, Thailand, on Facebook, 30 Jan. 2014, by Niramit Sareerudt. — Flowering of ไผ่หก (phai hok), presumably Dendrocalamus hamiltonii, Thailand, on Facebook, 8 Feb. 2014, by สวนไผ่นานาพันธุ์ สวน (suan phai nana phan suan). — Flowering of Dendrocalamus hamiltonii, China: Bamboo seeds @YunnanBambooCo on Facebook, 26 Nov. 2019.
Flowering cycle: 30–40 years [#1302]; 25, 30, 44 years [#1320].
Seed weight: ≈26,000 seeds/kg → ≈26 seeds/g [#1302].
Seed viability: Six to nine months under storage at 1–6 °C.
Comments:
(1) "There is substantial variation within this species and it has several distinct varieties" (C. M. A. Stapleton, 1994), two were described as var. undulatus and var. edulis.
(2) Thai plants under the name phai hok and identified as Dendrocalamus hamiltonii were described as having young culm internodes with gray hairs (A. Anantachot, 1991: p. 52-54 [#1041]).
Specimens: BS-0663 [BBG, SSG] (living plants), raised from seeds, the seeds from FMXG, Yunnan, China, collected in May 2011, received as "Dendrocalamus hamiltonii, 版纳甜龙竹 (ban na tian long zhu)", 30 May 2011; further seeds collected in Feb. 2012, not received, and in May 2014, received 11 Oct. 2014 (BS-0663-1).
Seed weight: 10 g ≈ 325–350 dried spikelets (husk-wrapped seeds).
Seed germination: Seed placed in moistened coir dust 100%, in June 2011, atmospheric humidity >70%, coleoptiles emerged after 6 days, germination rate moderate (40–60%).
Comments: Identification as Dendrocalamus hamiltonii is in doubt. The seedlings could represent a different Dendrocalamus species, maybe Dendrocalamus parishii.
"Dendrocalamus hamiltonii" in China — by courtesy of FMXG
"Dendrocalamus hamiltonii" (BS-0663): Seeds (left), young seedlings (right)
Dendrocalamus hamiltonii: Culm leaves, BS-0610 (left), MH-027 (right)
Specimen: BS-0610 (culm leaves), "ไผ่หกขาว" (phai hok khao), coll. by D.O., 5 Dec. 2010, at บ้านป่าแป๋ (Ban Pa Pae), อ. แม่แตง (Mae Taeng District), Chiang Mai, from a cultivated plant.
Characteristics: Culm-leaf sheaths rough; apex broad-triangular. Culm-leaf auricles upright, narrow-triangular to crescent-shaped, bristly. Culm-leaf ligule subentire. Culm-leaf blade erect, large, blade base almost as broad as sheath apex. Foliage-leaf blades large.
Specimen: MH-027 (living plants), แม่เหียะ (Mae Hia), Chiang Mai, cult., 8 Feb. 2012.
Characteristics: Culm-internodes whitish-pubescent. Culm-nodes with aerial roots. Culm-leaf sheaths rough, with rigid dark brown hairs; sheath apex broad-triangular. Culm-leaf auricles upright, narrow-triangular. Culm-leaf ligule serrulate. Culm-leaf blade erect, large, blade base almost as broad as the sheath apex. Foliage-leaf sheaths glabrous, or with a few whitish hairs, apex reddish when young. Foliage-leaf ligule long, chaffy. Foliage-leaf blades large.
Dendrocalamus cf. hamiltonii
Specimen: BS-0936 [S6] (living plant), Kanchanaburi, western Thailand, without precise location, received as Dendrocalamus cf. hamiltonii from บ. ต., 22 Nov. 2018.
Characteristics (immature plant): Rhizome pachymorph, short. Culms straight, erect, bending outwards above. Culm-internodes dull green, scattered with short whitish rough hairs when young; thick-walled. Culm-nodes glabrous, not or slightly prominent; nodal line with sheath scar marginally protruding; supranodal line obscure; with a farinose ring below the nodal line; basal nodes without aerial roots or root dots. Branch-buds solitary, subrotund, from the basal node up. Branches several, central one dominant, unbranched on the basal and lower culm; branching intravaginal; rebranching. Culm-leaves deciduous. Culm-leaf sheaths shorter than the internode; leathery, orange-green when young, light straw-colored when dry, glabrous or with some appressed short dark brown hairs; apex truncate; margins dark brown ciliate. Culm-leaf auricles small, erect, triangular, glabrous (perhaps with an early deciduous, very long and narrow extension). Culm-leaf ligule low, entire. Culm-leaf blade leathery, caducous, patent, triangular, light straw-colored when dry. Foliage-leaves ca. 8 per branchlet. Foliage-leaf sheaths green to orange-green when young, light straw-colored when dry, glabrous. Foliage-leaf auricles small, triangular, glabrous. Foliage-leaf ligule inconspicuous. Foliage-leaf blades, thick, light green, glabrous, very variable in size, mostly 27–30 cm long, 3–6 (8) cm wide.
Comments:
(1) The culm-leaf auricles of specimen BS-0936 are triangular and small, which is a key character of Dendrocalamus hamiltonii. Most of the other characteristics also match well with the description of this species. There are three notable differences: The culm-internodes are scattered with short rigid hairs and are not soft hairy (pubescent); aerial roots or root dots are absent on basal and lower nodes; the foliage-leaf blades are rather wide.
(2) The auricles, in particular, should be checked again when the plant has grown in size.
Dendrocalamus cf. hamiltonii (BS-0936): Upper section of a culm-leaf with auricle in a young culm.