Dendrocalamus sp. (TH: N) — hok wat chan

Thai name: ไผ่หกวัดจันทร์ (phai hok wat chan).

Distribution: THAILAND (North): Chiang Mai Province: วัดจันทร์, ต. บ้านจันทร์ อ. กัลยาณิวัฒนา, Wat Chan, Ban Chan Subdistrict, Kalayaniwattana District, wild(?) and cultivated, 950–1,000 m altitude.

Culm size: Height up to 25 m, diameter to 25 cm.

Description: Not available.

Uses: Culms for construction; plants for landscaping.

Comments:

(1) Flowers, but no seeds and no seedlings, were found near Wat Chan by ธ. บ. in Feb. 2018 (ธ. บ., pers. comm. and photos, 12 Feb. 2018).

(2) Judging from a set of photos of culm, culm-leaves, and a flowering branch of phai hok wat chan, I assume that this is not Dendrocalamus sinicus. In Dendrocalamus sinicus, the spikelets are longer thus appearing slim, and the culm-leaf sheaths are longer than the internode on the basal and lower culms (shorter in phai hok wat chan).

Specimens: BS-0929 [-] (herbarium material), from a cultivated living plant, วัดจันทร์, ต. บ้านจันทร์ อ. กัลยาณิวัฒนา เชียงใหม่, near Wat Chan, Ban Chan Subdistrict, Kalayaniwattana District, Chiang Mai, northern Thailand, coll. by ธ. บ., s.n., 10 Feb. 2018, received as "ไผ่หกวัดจันทร์ (phai hok wat chan)", 23 Feb. 2018. BS-0929A [-] (seeds), from the flowering branches of BS-0929, 26 Feb. 2018.

Characteristics: Culm-internodes thick-walled. Branches several, unequal. Culm-leaves deciduous. Culm-leaf sheaths 50 cm wide at the base, 47 cm long, rigid, dark straw-colored when dry, covered with brown appressed hairs; apex broadly rounded, with slightly depressed, 10–14 cm wide middle part, and with its center slightly convex-raised. Culm-leaf auricles waved, outwards tilted low rims, extending from the blade base (rim 7–10 mm high) to the sheath margin by decreasing height (to about 1 mm), glabrous and without bristles (when dry, fresh not seen). Culm-leaf ligule 2–5 mm high, denticulate. Culm-leaf blades thickly papery, persistent, reflexed, triangular, base 6–10 cm wide by 10 cm tall on the lower culm, about 31 cm tall on the mid-culm, and about 40 cm tall on the upper culm, dark straw-colored when dry, adaxially more or less hairy on the middle part near the base; apex attenuate. Foliage-leaf sheaths keeled, glabrous. Foliage-leaf auricles inconspicuous. Foliage-leaf ligule 2–3 mm high, subentire or denticulate. Foliage-leaf blades lanceolate, to 38 × 8 cm; base rounded to wedge-shaped; margins antrorsely scabrous; midrib proximally prominent beneath; pseudopetiole 5 mm long.

Comments:

(1) A few caryopses were found in the flowering branches. Lemma and palea were improperly removable from the caryopses, and remnants remained attached, possibly due to improper storage after collecting the herbarium material. The caryopses seem to have initiated germination and became soon thereafter (incompletely) dried.

(2) The spikelets of phai hok wat chan are much shorter than those in Dendrocalamus sinicus from Yunnan.

Specimens: MH-007 (living plant), Bamboo Center, Royal Project Foundation ศูนย์ไผ่ มูลนิธิโครงการหลวง T. Mae Hia, A. Mueang, Chiang Mai ต. แม่เหียะ อ. เมือง จ. เชียงใหม่, cult., as "ไผ่หกวัดจันทร์ (phai hok wat chan), Dendrocalamus sinicus Chia et J.L. Sun", Dec. 2008, June and Aug. 2009; MH-007-1 (living plant, flowering branch), same location, 8 Feb. 2012; MH-032 (living plant), same location, 16 Mar. 2016; MH-060 (living plant), same location, 29 Aug. 2017.

Characteristics: Habit tight caespitose. Rhizome pachymorph, short. Culms straight, erect, slightly bending outwards above. Young shoots emerge in July/August. Culm-internodes terete, green, with whitish fuzz when young, and thinly farinose; thick-walled on basal culm. Culm-nodes flat, sheath scar marginally protruding, with dense soft brownish hairs when young; with short aerial roots on basal culm. Branches several, central one dominant, two subdominant side branches, and some smaller ones, unbranched on the basal and lower culm; rebranching. Culm-leaves persistent and decaying on the culm (basal and lower culm), or late deciduous (mid and upper culm). Culm-leaf sheaths about 40 cm wide at the base, slightly wider than high, shorter than the internode, about two-thirds as long as the internode, thickly papery, straw-colored when dry, scattered with brown hairs; margins purplish when young; apex broadly rounded, middle part slightly concave-depressed. Culm-leaf auricles low waved rims from the blade base to the sheath margin, dark purplish when young, without bristles. Culm-leaf ligule about 3(?) mm high, dark purplish when young, entire or denticulate. Culm-leaf blades, erect to patent to reflexed, triangular, relatively small on the lower and mid-culm, about one-third as high as the sheath, dark purplish colored when young, adaxially hairy near base. Foliage-leaves about 12 per branchlet.

Comments: "ไผ่หกวัดจันทร์ (phai hok wat chan)" is identified and labeled as Dendrocalamus sinicus (S. Sungkaew & al., 2008). This identification is in question. In Dendrocalamus sinicus, culm-leaf sheaths are longer than the internode on basal and lower culm, whereas they are shorter in phai hok wat chan.

Specimen: BS-0269 [N2] (living plant), สถานีเกษตรหลวงปางดะ ต. สะเมิงใต้ อ. สะเมิง เชียงใหม่, Royal Agricultural Station Pangda, Samoeng Tai Subdistrict, Samoeng District, Chiang Mai Province, northern Thailand, cult., received as "ไผ่หกวัดจันทร์ ปล้องแดง" (phai hok wat chan plong daeng), 12 Sep. 2009.

Comments: At the Royal Agricultural Station Pangda, where this bamboo is kept in cultivation, it was said that two "forms" exist, one with reddish culms (ปล้องแดง plong daeng), the other with grayish culms (ปล้องเขา plong khao). I received the variant with reddish culms (BS-0269 [N2], 12 Sep. 2009), which was planted out at Bambusetum Baan Sammi, and when the plant had developed large culms, it became obvious that it was a species different from plants signposted as "ไผ่หกวัดจันทร์" (phai hok wat chan) at the Bamboo Center, Royal Project Foundation, Mae Hia. From 2015 onwards, the plant was large enough, with culms over 15 m tall, which clearly showed that characteristics of the culm-internode and culm-leaf were identical to Dendrocalamus asper. This specimen is therefore listed and described under Dendrocalamus asper.