Yushania rubrovaginata N. H. Xia, Y. H. Tong, J. B. Ni & X. Li 2025, comb. nov.

Yushania rubrovaginata (C. H. Hu) N. H. Xia, Y. H. Tong, J. B. Ni & X. Li comb. nov. Figs 1, 2, 3 Basionym. Sasa rubrovaginata C. H. Hu, Bamboo Research 2 (2): 59 (1985) Type. China. • Guangxi: Tianlin County, Langping Town, Cenwanlaoshan Mountain, elev. 2000 m, 26 Nov. 1957, Nanzhidi 5102 (lectotype N 019023168!, Fig. 1 A, designated here; isolectotype N 019023159!, Fig. 1 B) Description. Shrubby bamboo. Rhizomes pachymorph, necks 15–30 cm long, 3–5 mm in diameter, solid. Culms 1–3.5 m tall, 5–8 mm in diameter, diffuse; branches usually solitary at lower culm nodes, 2–3 at mid and upper culm nodes; internodes terete, 10–30 cm long, glabrous, densely purple-spotted, thickly white powdery below nodes, hollow; supranodal ridges raised. Culm buds solitary, long-ovate, yellow to light green, ciliate on the margin. Culm leaf sheaths persistent or tardily deciduous, ca. 1 / 2 as long as internodes, purple-red, densely brown hispid abaxially, densely ciliate on the margin; sheath scar prominent, with persistent remains of sheath base; auricles falcate, 3–5 × 1–2 mm; oral setae developed, radiate; ligule truncate, ca. 0.5 mm high; blades linear-lanceolate to lanceolate, reflexed, easily deciduous, margin serrulate. Foliage leaves 5–13 per ultimate branch; sheath glabrous, margin ciliate; auricles falcate, 1–3 × 0.5–1 mm; oral setae radiate, ca. 1 cm long; inner ligule truncate, ca. 1 mm high; outer ligule and pseudopetioles glabrous; blades broad-lanceolate to lanceolate, 17–26 × 3.5–6 cm, wavy when dry, glabrous, apex acuminate, base cuneate to obtuse; secondary veins 9–10 pairs, transverse veins conspicuous. Inflorescence unknown. Distribution and habitat. It is only found in Cenwang Mountain, Tianlin County, Guangxi, China. It grows on top of mountains at an altitude of 1968 to 2062.5 meters (the peak’s elevation). Phenology. New shoots from August to September. Chinese name. 红壳玉山竹 (Chinese pronunciation: hóng ké yù shān zhú). Notes. Hu (1985) described that the culm leaf auricles and oral setae of Yushania rubrovaginata are undeveloped (see Fig. 1). In fact, this bamboo does have developed culm leaf auricles and oral setae (Fig. 3 E, F). But the culm leaf auricles and oral setae are easy to fall off, which exactly happens to the type specimens of Y. rubrovaginata. Similarly, the culm leaf sheaths of the type specimens are glabrous on the mid and upper parts, and only the basal part is sparsely hispid. Actually, Y. rubrovaginata has a thoroughly hispid culm leaf sheath, and pits are left after the trichomes fall off (Fig. 3 E). Wang and Stapleton (2006) treated Sasa duplicata W. T. Lin & Z. J. Feng (1992) as a synonym of Y. rubrovaginata. However, the former has a leptomorph rhizome, rather than pachymorph rhizome. Actually, S. duplicata owns some characters that are the same as Pseudosasa cantorii (Munro) P. C. Keng ex S. L. Chen et al. (Zhu et al. 2006), such as glabrous internodes, the white powdery infranodal region, branch complement with one to three branches at each culm node, culm leaf sheath with ciliate margin, arcuate to truncate culm leaf ligules and falcate auricles with developed oral setae, foliage leaf sheath with ciliate margin, truncate ligules, developed oral setae and lanceolate to oblong-lanceolate blades with conspicuous transverse veins. Thus, S. duplicata is probably a synonym of P. cantorii, but more work needs to be done to ascertain this. There are another three Yushania species, viz., Y. cartilaginea T. H. Wen (1984), Y. chingii T. P. Yi and Y. rugosa T. P. Yi (1986), distributed in Cenwanglaoshan Mountain. Yushania rubrovaginata can be distinguishable from them by having branch complement with the solitary branch at lower culm nodes and two to three branches at mid and upper culm nodes, densely purple-spotted internodes, purple-red and densely brown hispid culm leaf sheath, and foliage leaf with developed and radiate oral setae. A key to these Yushania species is provided as follows.