玉山竹属(Yushania P. C. Keng)隶属于禾本科(Poaceae)竹亚科(Bambusoideae)青篱竹族(Arundi- narieae)青篱竹亚族(Arundinariinae)^[1]，约有87种^[1–3], 主要分布于我国，是亚热带高山区域所特有的一群竹类，分布海拔1 300~3 500 m。我国玉山竹属约有79种^[4–6]，主要分布于云南、四川、贵州、福建等南方亚热带高山区域，西藏及台湾亦有分布。贵州省平均海拔约可达1 100 m，地貌以山地、丘陵为主，适合竹类生长，据统计该省有玉山竹属12种^[7]。玉山竹属的主要特征为：灌木状竹类；根状茎粗短型，秆柄细长，节间通常实心；箨痕明显隆起，秆环在具分枝的节上微隆起，秆每节一分枝或数分枝；叶片小到中型，小横脉明显；花序呈总状或圆锥状, 生于具叶小枝顶端，花序分枝和小穗柄的腋间通常具小瘤状腺体；真小穗，颖2枚；鳞被3；雄蕊3; 柱头2或稀可3^{[5, 8–9]}。

2019年，我们在贵州省黎平县老山界进行植物考察的过程中，发现了一种未知的小灌木状竹类植物。该种的根状茎为长颈粗短型，箨鞘宿存，显系玉山竹属的植物。此外，该种的箨鞘外面密被黄褐色或紫色疣基刺毛，箨耳和叶耳弯曲呈镰刀状，且具发达的长鞘口繸毛，而显得尤为特别。经查阅相关文献和比对相近种类的标本之后^{[2, 9–12]}，我们发现该种实为玉山竹属的一个新种，因此在这里予以发表。

黎平玉山竹     新种  图 1

Yushania lipingensis Z. Yang, Z. X. Zhang & Y. H. Tong, sp. nov. (Fig. 1)

Diagnosis: Yushania lipingensis is morphologically similar to Y. auctiaurita T. P. Yi, but differs in its culm leaf sheath densely yellow-brown or purple antrorsely setose (vs. yellow-brown retrorsely setose) abaxially, auricles strongly curved to falcate (slightly curved to oblong-falcate) with 3–9 mm (vs. 3–6 mm) long radiating oral setae (vs. straight forward), ligule with a truncate and densely ciliolate apex (vs. with an arcuate and glabrous apex), blades adaxially puberulent (vs. glabrous), foliage leaf auricles strongly falcate with 3–11 mm (vs. 2–7 mm) long radiating oral setae (vs. straight forward) and blades with 5–6 pairs (vs. 5–9 pairs) of secondary veins.

Type: CHINA. Guizhou, Qiandongnan Miao and Dong Autonomous Prefecture, Liping County, Dehua Town, Wumeng Village, Laoshanjie, 26°29ʹ13″ N, 108°39ʹ5″ E, alt. 1 540 m, 19 May 2020, Y. H. Tong & F. L. Chen TYH-2478 (holotype: IBSC).

Description: Shrubby bamboos. Rhizome pachymorph, long-necked; neck 16–22 cm long, 2– 3 mm in diam.; internodes ca. 5 mm long, 3–6 mm in diam., solid. Culms 50–90 cm tall; internodes 6–12 cm long, 2–6 mm in diam., terete or proximally flattened above branches, not ribbed, initially purple spotted, glabrous, solid, thickly white powdery below nodes; supra-nodal ridges level or slightly prominent when branching, sheath scar prominent, glabrous; intranode 3–6 mm high, glabrous. Culm buds oblong, upper margins densely ciliate. Branches often 1 at lower nodes to 3 at middle or upper nodes, slightly ascending, central branch subequal or equal to culm. Culm leaf: sheaths persistent, thinly leathery, 1/3–1/2 as long as internodes, abaxially densely yellow-brown or purple antrorsely setose especially toward base, setae 0.5– 2.5 mm long, longitudinal ribs conspicuous, margins densely brown ciliate, cilia 0.5–1.5 mm long; auricles developed, strongly curved falcate, 3–5 mm×1–4 mm; oral setae 8–14, 3–9 mm, yellow-brown to purple, erect or curly, radiating, scabrid; ligule 0.6–1 mm high, apex truncate, densely white ciliolate, ciliola ca. 0.3 mm long; blades narrowly lanceolate or triangular- lanceolate, erect at lower nodes and reflexed at upper nodes, abaxially nearly glabrous, adaxially scabrid and puberulent, margins serrulate, sometimes sinuous, usually involute. Ultimate branch robust, 2–8-foliate. Foliage leaf: sheaths 2.5–5.5 cm long, nearly glabrous, longitudinal ribs conspicuous, margins yellow-brown or purple long ciliate especially toward base, cilia ca. 1 mm long; auricles developed, brown to purple, curved falcate, 1–3 mm×0.5–2 mm, easily deciduous when old; oral setae 5–11, 3–11 mm long, yellow- brown to purple, erect to curly, radiating, scabrid, usually deciduous when old; ligule 1–2 mm high, apex truncate to slightly arcuate, sometimes ciliolate, ciliola easily deciduous; outer ligule developed, apex ciliolate; blades lanceolate, 3–9 cm×1–3 cm, initially abaxially pubescent, glabrescent when old, margins initially serrulate, entire when old, rugose when dry, secondary veins 5–6-paired, transverse veins distinct, apex acuminate, base truncate to cuneate. Inflorescence unknown.

小灌木状竹类。根状茎长颈粗短型；秆柄长16~22 cm，直径2~3 mm，节间长约5 mm，实心。秆高50~90 cm；节间长6~12 cm，直径2~6 mm, 圆筒形或在具分枝一侧基部略扁平，不具肋纹，幼时具紫色斑点，无毛，实心，节下方被一层厚白粉；秆环平或稍隆起，尤其在具分枝节上肿胀，箨痕明显隆起，无毛；节内长3~6 mm，无毛。秆芽长圆形，上部边缘密生纤毛。秆基部单分枝，中上部可达3分枝，略向上斜举，中央一枚与秆近等粗。箨鞘宿存，薄革质，长度为节间的1/3~1/2，背面具向上的黄褐色或紫色的疣基刺毛，毛长0.5~2.5 mm, 向上部渐稀疏，纵肋明显，边缘密生0.5~1.5 mm的褐色长纤毛；箨耳发达，明显弯曲呈镰刀状，长3~5 mm，宽1~4 mm，边缘具8~14条黄褐色至紫色的劲直或弯曲的放射状繸毛，繸毛长3~9 mm, 粗糙；箨舌高0.6~1 mm，先端截平，边缘密生白色的短纤毛，纤毛长约0.3 mm；箨片狭披针形或三角状披针形，秆基部的直立，秆上部的外翻，背面近无毛，腹面被微柔毛，粗糙，边缘具小锯齿，有时呈波曲状，常内卷。末级小枝较坚硬粗壮，具叶2~8；叶鞘长2.5~5.5 cm，近无毛，纵肋明显，边缘具长约1 mm的褐色或紫色长纤毛，基部尤甚；叶耳发达，褐色至紫色，弯曲呈镰形，长1~3 mm，宽0.5~ 2 mm，边缘具5~11条黄褐色至紫色的劲直或弯曲的放射状繸毛，繸毛长3~11 mm，粗糙，老后易脱落；叶舌高约1~2 mm，先端截平至微圆拱，有时边缘具易脱落的短纤毛；外叶舌明显，顶部具极短纤毛；叶柄长2~4 mm；叶片披针形，长3~9 cm，宽1~3 cm，幼时下表面被柔毛，后变无毛，边缘幼时有小锯齿，后变全缘，干后皱缩，次脉5~6对，小横脉明显，叶尖渐尖，叶基截平至楔形。花序未见。

模式标本： 贵州省黔东南苗族侗族自治州黎平县德化乡乌孟村，老山界山顶，26°29ʹ13″ N，108° 39ʹ5″ E，海拔1 540 m，2020年5月19日，童毅华、陈丰林TYH-2478 (主模式：IBSC)。

分布及生境： 目前仅见于贵州省黎平县老山界。生于海拔约1 540 m的山顶灌丛中，伴生种主要有新木姜子[Neolitsea aurata (Hay.) Koidz.]、幌菊[Ellisiophyllum pinnatum (Wall.) Makino]、黄毛草莓(Fragaria nilgerrensis Schlecht. ex Gay)、矩叶卫矛(Euonymus nitidus Benth.)等。

词源：种加词源自模式产地“黎平”的汉语拼音，中文名称为“黎平玉山竹”。

讨论：目前玉山竹属依据秆每节分枝数目可分为玉山竹组sect. Yushania和短锥玉山竹组sect. Brevi- paniculatae T. P. Yi，前者秆每节分枝较少，仅具1分枝或中上部分具3~5(8)分枝^[11]，约有32种；后者秆每节具5~9或更多分枝，约有47种。该新种秆下部具1分枝，中上部具3(4)分枝，因此应隶属于玉山竹组，其形态上与同组的显耳玉山竹(Yushania auctiaurita T. P. Yi)相似，两者均为小灌木状，秆较细，幼秆无毛，有紫色斑点，在节下方有一圈厚白粉；秆下部的节具1分枝而中上部每节具3或4分枝；箨鞘背面被刺毛，边缘密生长纤毛; 箨片反折，长三角形或披针形；末级小枝具叶3~8, 叶鞘边缘具短纤毛；叶片披针形，干后常皱缩，老后两面均无毛。但本种箨舌先端截平，边缘密生短纤毛，箨鞘背面密被向上的黄褐色或紫色疣基刺毛; 箨耳和叶耳均弯曲呈镰刀状，鞘口繸毛较长，呈放射状。而显耳玉山竹箨舌先端近圆拱形，无毛；箨鞘背面被向下的黄褐色疣基刺毛；箨耳和叶耳长圆形，稍弯曲，鞘口繸毛较短，直立，前伸，不呈放射状。两者详细的形态性状对比见表 1。

致谢 感谢西南林业大学的张玉宵博士和昆明植物研究所的叶夏英博士提供显耳玉山竹的照片以供比对；感谢黎平县太平山自然保护区综合科考及编制服务项目和黎平县林木种植资源清查工作服务项目的支持。