Cephalostachyum elevatissimum (Hsueh & T. P. Yi) D. Z. Li, Y. X. Zhang & Y. J. Chen, 2025

Chen, Yu-Jin, Chen, Mei, Zhou, Meng-Yuan, Xu, Zu-Chang, Zhang, Yu-Xiao, Liu, Jing-Xia & Li, De-Zhu, 2025, Further investigation of Melocalamus (Poaceae, Bambusoideae) in China based on Skmer analysis and morphology, PhytoKeys 259, pp. 177-198 : 177-198

Cephalostachyum elevatissimum (Hsueh & T. P. Yi) D. Z. Li, Y. X. Zhang & Y. J. Chen comb. nov.

Fig. 4 Local names. Sang Rong, Ping Er. Chinese name. “ 西藏空竹 ” (xī zàng kōng zhú ).

≡ Melocalamus elevatissimus Hsueh & T. P. Yi , J. Bamboo Res. 2 (1): 28, 1983.

Type.

China • Xizang: Linzhi City, Motuo County, Beibeng Town, Deergong , alt. 940–2000 m, 15 Aug 1977, T. P. Yi 77183 (holotype, SIFS!, without barcode) .

Description.

Perennial. Rhizomes pachymorph, short-necked. Culms apically scrambling, ca. 17 m long, 1.4–3 cm in diam.; internodes terete, glabrous, 40–90 (– 120) cm long, wall 0.2–0.4 cm thick; nodes flat, glabrous; white powdery below the nodes; sheath scars prominent. Primary branch buds solitary, ovate-elliptical, compressed. Branches many, subequal or occasionally with a dominant branch replacing main culm. Culm leaves tardily deciduous, 24–38 cm × 8–12 cm, 2 / 5 to 1 / 2 as long as the internodes; sheaths leathery, long-triangle, with appressed light-yellow spiny hairs abaxially, margins glabrous, apex U-shaped and projecting upward sides, papery, with fimbriate grey-white long oral setae; auricles absent; ligules truncate, short, ca. 1 mm in length, margin extremely shortly ciliolate or subglabrous; blades linear-lanceolate, erect or reflexed, 5–30 cm × 1–1.9 cm. Foliage leaves 6–9 per ultimate branch; sheaths 8–16 cm long, abaxially glabrous, apex with fimbriate grey-white long oral setae, 4–11 mm long; margins with fringed cilia, 6–15 mm long; auricles absent; inner ligules truncate, dark-purple, ca. 1 mm in length; outer ligules present, truncated; blades oblong-lanceolate, 17–28 cm × 3–9 cm, with white pubescence abaxially, margins coarse, secondary veins 5–12 paired. Inflorescence and caryopsis unknown.

Phenology.

New shoots May to August.

Additional specimens examined.

China • Xizang: Linzhi City , Motuo County, alt. 1995 m, 15 Jul 2021, Z. Y. Xiahou XHZY 2021003 ; • ibid., 30°1'7.097"N, 94°59'44.77"E, alt. 2061 m, 13 Jun 2023, P. F. Ma et al. BPG II 23141 ; • ibid., 29°38'48.75"N, 95°29'4.70"E, alt. 1903 m, 14 Jun 2023, P. F. Ma et al. BPG II 23148 ; • ibid., 29°14'37.071"N, 95°11'16.95"E, alt. 1302 m, 15 Jun 2023, P. F. Ma et al. BPG II 23159 ; • ibid., 29°10'50.10"N, 95°8'36.56"E, alt. 1736 m, 15 Jun 2023, P. F. Ma et al. BPG II 23163 ; • Xigaze City, Yadong County, Xiayadong , alt. 1625 m, 16 Jul 2021, J. D. Ya et al. 21 CS 20510 ; • ibid., 27°14'4.89"N, 89°1'2.89"E, alt. 1684 m, 6 Jun 2023, P. F. Ma et al., BPG II 23019 .

Note.

Melocalamus elevatissimus was the first species of Melocalamus published in China ( Yi 1983), which has a narrow distribution area in southern Xizang, confined to Motuo and Yadong, as well as the Yarlung Zangbo Grand Canyon National Nature Reserve, Xizang ( Wu et al. 2022). Cephalostachyum elevatissimum does not overlap with the distribution area of other Melocalamus species (distributed in the Yunnan, Guangxi and Hainan Provinces of China, as well as Thailand, Myanmar, Vietnam and other Southeast Asian countries), but shares a common range with Cephalostachyum (Fig. 5 ). In addition, Melocalamus are predominantly found at altitudes ranging from 200 to 1300 m, while C. elevatissimum in Xizang mainly inhabits areas in higher altitudes (mainly 1300 to 2060 m).

Figures

Figure 4. Cephalostachyum elevatissimum (Hsueh & T. P. Yi) D. Z. Li, Y. X. Zhang & Y. J. Chen. A. Habitat; B, H. Branch complement; C. A complete internode with culm leaf sheath; D. Culm leaf sheath apex; E. Node and culm bud; F. Transection of main culm; G. Foliage leaf sheath.

Figure 5. Geographical distribution variations of Cephalostachyum elevatissimum (blue dots), other species of Cephalostachyum (red dots) and species of Melocalamus (black dots).