Bambusa pervariabilis × Dendrocalamus latiflorus

Specimen: BS-0725 [E1] (living plant); introduced from Yunnan, China, by C. S., received 23 Jan. 2012.

Thai name: ไผ่เมฆขาว (phai mek khao) (according to คุณศิรภพ Khun Siraphop of สวนไผ่นานาพันธุ์ Nana Phan Nursery, Prachin Buri, 19 Jan. 2019, pers. comm.).

English name: White Cloud Bamboo.

Characteristics: Habit tight caespitose. Rhizome pachymorph, 15–20 cm long, short-necked. Culms straight, stiffly erect, older culms slightly bending outwards, to 17 m tall. Young shoots light bluish green with erect broad triangular to lanceolate mid-green culm-leaf blades, scattered short dark hairy; emerge from April/May to August. Culm-internodes terete, 32–44 (49) cm long, dull mid-green, glabrous, smooth; thickly but ir­regu­larly covered with a powdery white deposit, easy to wipe off; diameter to 8 cm; moderately thick-walled to thin-walled, wall widths 0.4–1.2 (1.9) cm on the lower and mid-culm (→ table with culm size dimensions). Culm-nodes glabrous, smooth, flat; sheath scar marginally protruding 0.5–1 mm; supranodal line discernible, without a ridge, 6–10 mm above the nodal line; without a white farinose or sericeous ring below or above the sheath scar; with aerial roots on the basal nodes. Branch-buds solitary, from the basal node up. Branches 1 (on mid-culm) to several on upper nodes, the central one very dominant; unbranched on the basal and lower culm, usually the first 11–15 nodes without branches, except for occasional short thin rudimentary branches on the lower culm; branching intravaginal; rebranching. Culm-leaves deciduous. Culm-leaf sheaths 26 cm wide at the base, 28–29 (33) cm long, 2/3 as long as the internode, thickly leathery, rigid, glossy light green to dull light bluish-green and changing to yellowish-green when young, dull light straw-colored when dry, abaxially irregularly scattered with short dark brown to blackish hairs, not farinose, adaxially with irregular patches of a powdery white deposit; margins eciliate; apex horizontal, somewhat waved, with the middle part slightly convex. Culm-leaf auricles rim-like, slightly bent outwards and waved, about 10 mm long and 1–2 mm high, dark green and glossy when young; with short undulating and interlacing white bristles, more or less deciduous with age. Culm-leaf ligule 3–4 mm high, denticulate, occasionally with a few early caducous bristles. Culm-leaf blades coriaceous, persistent, erect, mid-green when young, light straw-colored when dry, broadly triangular, basal edges rounded, 6.5 cm wide near the base, 16 cm long on lower culm, longer (26 cm) on mid and upper culm; width of the junction with the sheath 5 cm; abaxially scattered with short brown hairs throughout, becoming blackish with age, adaxially glabrous, rough; apex acuminate, sharp-pointed. Foliage-leaves (5) 7–10 per branchlet. Foliage-leaf sheaths yellowish green when young, glabrous; margins eciliate. Foliage-leaf auricles inconspicuous, rim-like, with deciduous 3–6 mm long whitish bristles. Foliage-leaf ligule 1–2 mm high, inconspicuous, entire (or denticulate or ciliolate?); outer ligule present. Foliage-leaf blades stout, lanceolate, 20–30 (37) × 2.5–4 (7) cm, mid to dark green above, dull mid-green beneath, glabrous on both surfaces; base rounded to oblique cuneate; apex acuminate; margins smooth or antrorsely scaberulous; midrib proximally slightly prominent and light green beneath; pseudopetiole 4–6 mm long. Flowers and seeds are unknown.

Uses: Shoots for food, palatable, without a bitter taste; culms for construction and paper pulp; plants for landscaping, suitable for screening and good for windbreaks.

Cultivation requirements: Easy and fast-growing; preferably in full sun, on sandy loam to clay loam, normal moisture-retentive to moist with good drainage.

Comments:

(1) The hybrid BS-0725, when received, was labeled as "7-B. pervariabilis×D. daii No. 3- 4". This could be Bambusa pervariabilis McClure × Dendrocalamopsis daii Keng f. No. 3, syn. Bambusa pervariabilis McClure × Dendrocalamopsis grandis Q. H. Dai & X. L. Tao ex Keng f. No. 3; Chinese name: 撑绿竹3号 (chēng lǜ zhú 3 hào). There is no confirmation of this identification. A photo of "Bambusa pervariabilis X Dendrocalamus latiflorus No. 7 FMXG" was published in H. C. Tan, 2012: 37 [#1195], which might be identical to specimen BS-0725.

(2) The label indicates that the plant derives from two parents: Bambusa pervariabilis McClure and Dendrocalamopsis daii Keng f. The correct name of the latter parent is Dendrocalamopsis grandis Q. H. Dai & X. L. Tao, if Dendrocalamopsis is accepted at generic rank, or Bambusa grandis (Q. H. Dai & X. L. Tao) Ohrnb., if Dendrocalamopsis is considered a taxon of infrageneric rank (Flora of China, taxon ID 250070934). At Bambusetum Baan Sammi, members of both parents have been present as mature or nearly mature plants in the living collection: Bambusa pervariabilis 'Viridistriata' (BS-0259), and Bambusa grandis (BS-0458), but they were abandoned later, the former in 2020, the latter in August 2022.

(3) BS-0725 is neither similar in characteristics (culm-leaves, branching, foliage-leaves) to Bambusa pervariabilis nor Dendrocalamopsis daii (Bambusa grandis). The shape of auricles in the culm-leaves is different, there is low branching in both species but not in BS-0725, and the foliage-leaf blades are considerably larger in BS-0725 than in Bambusa pervariabilis, and somewhat larger than in Bambusa grandis. Judging from the overall characteristics, it seems to me more likely that Dendrocalamus latiflorus is one of the parents of this hybrid, and the other parent could be Bambusa grandis. However, this is merely speculative, although hybridization with Dendrocalamus latiflorus was carried out in China, and two other hybrid plants with Dendrocalamus latiflorus as one of the parents were received in 2012.

Specimen: BS-0726 [C3] (living plant); introduced from Yunnan, China, by C. S., received 23 Jan. 2012.

Characteristics: They have not yet been observed in detail except for the culm-leaf, which matches perfectly with those of BS-0725.

Comments:

(1) The hybrid BS-0726, when received, was labeled as "8-B. pervariabilis×D. latiflorus ×B. textilis No. 1 - 3". This could be Bambusa pervariabilis McClure × (Dendrocalamus latiflorus Munro × Bambusa textilis McClure) No. 1; Chinese name: 撑麻青竹1号 (chēng má qīng zhú 1 hào). There is no confirmation of this identification.

(2) A photo was published in H. C. Tan, 2012: 36 [#1195].

(3) This plant remains temporarily under observation at Bambusetum Baan Sammi. Ten years later, in 2022, this specimen appears to have nearly reached its maximum height. No differences from BS-0725 could be found, except that the height and diameter (to 6 cm) of the culms are only slightly smaller.