王 勇
(陕西理工大学生物科学与工程学院,汉中 723000)
笔者在大巴山区考察时,发现兰科(Orchidaceae)山兰属(Oreorchis Lindley)植株正在开花。这些植株形态与山兰(O.patens(Lindley)Lindley)十分相似,但在形态和物候上存在差异,可以区别。在营养体形态方面,这些植株体型较大,假鳞茎(2~3 cm×1~2.5 cm)和叶片(30~40 cm×2~3.5 cm)均明显大于山兰(假鳞茎1~2 cm×0.5~1.5 cm,叶13~30 cm×0.4~2 cm);前者在假鳞茎顶端多数具3片叶,少数为2 片,而后者每个假鳞茎顶端通常只有1片叶,罕2片。此外,本次发现的开花植株叶柄顶端有明显关节,不同于《中国植物志》[1]、《Flora of China》[2],以及Pearce N.和Cribb P.[3]对山兰叶的描述为“基部收狭为柄”。在花部形态方面,我们发现的开花植株的花朵唇瓣爪长度约为总长1/2,唇瓣侧裂片直立,唇瓣中央纵褶片于末端(2唇瓣侧裂片基部之间)膨大并汇合为船形附属物,呈鲜艳的橙红色,而山兰花朵唇瓣爪较短,长度通常仅为总长约1/4,唇瓣侧裂片向下镰曲,唇瓣纵褶片脊状,白色至浅黄色[1~6](见图2),易于区别。同时,在物候方面,本次发现的植株秋季生叶,经冬不凋,翌年4月凋落,夏季无叶,5月开花,花期结束后假鳞茎即休眠,于9月在新生的假鳞茎顶端生出2~3片叶;不同于山兰四季常绿,春季新叶长出同时老叶凋落(周繇,私人通信)。根据以上特征,本次发现的山兰属植物是一个新种,特命名为巴山山兰(Oreor⁃chis bashanensis),并描述如下。
Oreorchis bashanensis Wang Yong sp. nov.Fig.1:A-F
Species nova Oreorchis patens(Lindley)Lindley similis,a qua foilia 2-3,appendice carinatus aurantius supra medium inserta bene differt.
Plant terrestrial,up to 70 cm tall. Leaves fall when flowering,Pseudobulb ovoid to subellipsoid,2-3 cm×1-2.5 cm,2- or 3-noded,partly covered by scarious brown sheaths,persisting and forming a chain of pseudobulbs connected by a short rhizome.Leaf 3,or sometimes 2,linear or narrowly lanceolate,plicate,30-40 cm×2-3.5 cm,apex acuminate,gradually tapering at base. Petioles 5-8 cm long,sheathed. Inflorescence 35-70 cm,with 2 or 3 tubular sheaths below middle;rachis 10-20 cm,30-40 flowered;floral bracts narrowly lanceolate,3-5 mm.Flowers greenish brown,lip greenish brown on claw,midlobe and lateral lobs white with purple spots at apex;pedicel and ovary 10-15 mm;dorsal sepal narrowly obovate,ca. 9 mm×2 mm,apex slightly obtuse;lateral sepals narrowly ablong,ca. 8 mm×2 mm slightly falcate,apex acute;lip oblong-obovate,8 mm×3.5-5 mm,3-lobed below middle;long clawed at base(claw of midlobe ca. 4mm),lateral lobes erect,linear,ca.3 mm×0.7 mm,apex obtuse;apex of mid-lobe flabellate,up to 5.8 mm at widest point when spread,margins sinuate;disc with two longitudinal lamellae,up to 4 mm long,swell and fused into a carinate appendage,which is orange in color,projecting between the insertion points of lateral lobs.Column ca.4.5 mm,base thickened.Capsule oblong,ca.15 mm×7 mm.Fl.May-Jun,fr.Jul-Oct.
陕西(Shaanxi)宁强县,红石梁国家森林公园(Ning Qiang Xian,Hong Shi Liang National forest park),alt.1 800 m,落叶阔叶林下(under deciduous forest),2019-05-17 王勇(Wang Yong)20190517008(Holotype HZTC陕西理工大学植物标本馆)。
原记载世界山兰属共16 种,我国11 种[1~4,6],至此分别增为17 种和12 种,大巴山地区的兰科植物的种数也由原记载的86种[7]增至87种。