Melocalamus orenudus (McClure) D. Z. Li & J. X. Liu

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

Melocalamus orenudus (McClure) D. Z. Li & J. X. Liu .

Fig. 6 Chinese name. “ 无耳梨籐竹 ” (wú ěr lí téng zhú ).

Melocalamus orenudus (McClure) D. Z. Li & J. X. Liu , Plant Divers. 45: 137, 2023.

≡ Dinochloa orenuda McClure , Lingnan Univ. Sci. Bull. 9: 18, 1940.

= Melocalamus utilis (McClure) D. Z. Li & J. X. Liu , Plant Divers. 45: 138, 2023, syn. nov. ≡ Dinochloa utilis McClure Lingnan Univ. Sci. Bull. 9: 20, 1940.

Type.

China • Hainan: Lingshui County, Chim Shan, Fan Maan Ts’uen and vicinity , 3–20 May 1932, H. Fung 20230 (holotype, US!, Catalogue No.: 2802829, Barcode: 00065462) ; • Ledong County, Jianfengling National Nature Reserve , 18°42'21.03"N, 108°52'6.04"E, alt. 826 m, 02 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23238 (epitype designated here, KUN!) .

China • Hainan, Ling Shui District, Chim Shan, Fan Maan Ts’uen and vicinity , 4–20 May 1932, McClure 20136 (holotype, US!, Catalogue No.: 2802831, Barcode: 00065464; isotype, US!, Catalogue No.: 2767635, Barcode: 00036336; No.: 2767636, Barcode: 00036337) .

Description.

Perennial. Rhizomes pachymorph, short-necked. Culms slender, 10–20 m long, 2–5 cm in diam., wall ca. 0.5 cm thick; internodes initially with white pubescence, 30–60 cm long; nodes prominent; sheath scars with a ring of white-yellow tomenta above and below. Branches several to many, with one dominant branch sometimes replacing main culm. Culm leaves shorter than internode; sheaths leathery, with white spiny hairs and powder abaxially, apex slightly concave; auricles narrow, extending upwards or absent; oral setae absent; ligules 1–2 mm in length, denticulate; blades lanceolate, round / cordate at the base, recurved. Foliage leaves 7–15 per ultimate branch; sheaths glabrous, tender sheaths are covered with easily deciduous short pubescence and white powder; auricles narrow or absent; ligules entire, ca. 1 mm in length; blades length 13–21 cm × width 3–4.5 cm, with white pubescence abaxially; margins coarse.

Flowering branches lateral or terminal; internodes 1–15 cm long, with white pubescence. Pseudospikelets lanceolate, top and edge purple, bottom yellow-green, 1–1.2 cm long, several to many clustered on nodes, glomerate, mixed with some small sterile and hay bracts; 3 florets in each psedospikelet with the top one sterile, fertile ones sessile. Glumes 2–3, ovate, 2–5 mm long, 2–3 mm wide, margins smooth. Fertile lemma lanceolate, thick membranous, glabrous, yellow, with top and edge purple, ca. 6–12 mm long. Palea nearly equal as lemma in size, lanceolate, membranous, navicular, 2 keels, margins with white cilia, yellow, with top and edge purple. Lodicules 3, 2 equal-sized, ca. length 2.7 mm × width 1.3 mm, one smaller, ca. length 2 mm × width 1 mm, bottom transparent with top light-purple, margins with long cilia. Stamen 6, distinct, anthers purple-red, sometimes yellow, 5–6 mm long, filament white. Ovary ovate-lanceolate, yellow-green; style 1, stigmas 3, plumose, white. Caryopsis unknown.

Phenology.

New shoots May to July.

Additional specimen examined.

China • Hainan: Baoting County, Ganzhaling Nature Reserve , 22 Aug 2018, J. X. Liu & Z. C. Xu Liujx 18063 ; • Baoting County, Nangai 2 Road , 18°32'47.28"N, 109°31'34.43"E, alt. 354 m, 01 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23232 ; • ibid., 18°33'5.01"N, 109°33'48.76"E, alt. 238 m, 01 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23234 ; • Changjiang County, Bawangling National Nature Reserve , 19°7'13.04"N, 109°6'37.25"E, alt. 388 m, 03 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23244 ; • Lai area, Hung Mo Shan and vicinity , 16 May 1929, Tsang, Tang & Fung, 17725 ( SYS!) ; • Lingshui County, Chim Shan, Fan Maan Ts’uen and vicinity , 4–20 May 1932, F. A. McClure 20087 ( SYS!) ; • Lingshui County, Diaoluo Mountain National Nature Reserve , 18°41'21.12"N, 109°52'43.68"E, alt. 612 m, 10 Jul 2017, M. Y. Zhou et al. zmy 034 ; • ibid., 24 Aug 2018, J. X. Liu & Z. C. Xu Liujx 18076 ; • ibid., 18°42'2.48"N, 109°50'10.38"E, alt. 511 m, 31 Oct 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23221 ; • ibid., 18°40'8.33"N, 109°54'10.75"E, alt. 236 m, 31 Oct 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23223 ; • Ledong County, Jianfengling National Nature Reserve , 18°43'15.09"N, 108°49'54.31"E, alt. 535 m, 02 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23243 ; • ibid., 18°42'21.02"N, 108°52'6.03"E, alt. 826 m, 02 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23238 ; ibid., 118°42'0.42"N, 08°51'52.07"E, alt. 753 m, 19 Jun 2024, M. Y. Zhou, J. X. Liu & Y. J. Chen CYJ 2024029 (with fl.) ; • ibid., 18°40'57.61"N, 108°52'46.39"E, alt. 640 m, 19 Jun 2024, M. Y. Zhou, J. X. Liu & Y. J. Chen CYJ 2024032 (with fl.) ; • ibid., 18°43'22.15"N, 108°50'3.24"E, alt. 633 m, 21 Aug 2024, M. Y. Zhou, J. X. Liu & Y. J. Chen CYJ 2024052 ; • Qiongzhong County, Shipo Village , 18°51'59.97"N, 109°45'52.25"E, alt. 316 m, 4 Nov 2023, M. Y. Zhou, J. X. Liu & Z. C. Xu BPG II 23259 ; • Sanya City, Tianya District, Ming Shan , 26 Aug 2018, J. X. Liu & Z. C. Xu Liujx 18079, Liujx 18081 ; • Sanya City, Tianya District, Ya Lin , 27 Aug 2018, J. X. Liu & Z. C. Xu Liujx 18084, Liujx 18088 .

Note.

Melocalamus utilis and M. orenudus were initially described as independent species of Dinochloa by McClure (1940). Based on molecular phylogeny, Liu et al. (2023) transferred them into Melocalamus . Phylogenetically, one sampled individual of M. utilis mixed into one clade which made M. orenudus paraphyletic in dd-RAD tree ( Liu et al. 2023). We sampled more individuals in the Skmer analysis and resulted in a similar topology. Melocalamus utilis and M. orenudus exhibit high morphological similarity. Furthermore, these two species occupy overlapping distribution ranges, with type specimens collected from the similar location as “ Lingshui Dist., Chim Shan, Fan Maan Ts’uen ”, in Hainan Province (the type locality now belongs to Sandao Zhen of Baoting County, Fanna Village to Shougong Jianlin). Based on morphological and genetic evidence, as well as geographical distribution data, we conclude that M. utilis and M. orenudus are conspecific. Since both names were simultaneously published by the same author in the original work and no explicit choice of priority was made ( McClure 1940), we propose to treat M. utilis as a synonym of M. orenudus following the International Code of Nomenclature ( ICN) ( Turland et al. 2025).

In October 2023, we collected a few flowering individuals of M. orenudus in Jianfengling National Nature Reserve, Hainan. We conducted follow-up investigations in this area in June and August 2024, respectively. In total, we found two clumps of M. orenudus in the flowering stage that were relatively close to each other and collected three flower-bearing specimens ( BPG II 23238, CYJ 2024029 and CYJ 2024032). The descriptions of inflorescence are mainly based on the specimen BPG II 23238, which provided the epitype (designated here) of the species.

Figures

Figure 6. Melocalamus orenudus (McClure) D. Z. Li & J. X. Liu. A. New shoot, showing sheath auricle and ligule; B. Foliage leaves, showing foliage leaf sheaths; C. Habitat; D. Culms with culm leaf sheaths, branch complement and node with bud; E, F, H. Inflorescence and pseudospikelets; G. Stamens (s), lemma (le), palea (p), ovary (o), three lodicules (lo) and two glumes (g).