铁线莲属黄花铁线莲组修订

对毛茛科铁线莲属Clematis的黄花铁线莲组sect. Meclatis进行了全面修订, 确定此属含13种和13变种(包括1新变种和2新变种等级); 写出了此组的分类学简史和地理分布, 并对其在铁线莲属中的系统位置和组内诸种的亲缘关系进行了讨论; 还写出了此组的分种、分变种检索表, 以及各种植物的形态描述、地理分布、生长环境等, 并附有各种的插图。此组的花构造与对枝铁线莲组sect. Brachiatae的近似, 与后者在亲缘关系上相近, 区别在于此组的萼片通常斜上方开展, 呈黄色, 被毛的花丝下部变宽, 呈狭披针形, 而在对枝铁线莲组, 萼片水平开展, 呈白色, 被毛的雄蕊花丝呈狭条形, 下部不变宽; 二组可能均起源于欧洲铁线莲组的sect. Clematis subsect. Clematis, 因此, 均应是隶属欧洲铁线莲亚属subgen. Clematis的成员。根据对此组植物形态特征的分析, 观察到以下演化趋势: (1)叶的颜色由于适应干旱气候, 由绿色变为灰绿色; (2)卵形或宽卵形、掌状分裂、边缘具齿的小叶可能是原始的特征, 而披针形或条形、不分裂、全缘的小叶是衍生的特征; (3)单独、顶生、只是花梗的花是由具花序梗和二苞片的聚伞花序发生减化(reduction)而衍生的; (4)萼片形状的演化趋势与小叶形状的演化趋势近似, 也由卵形演变到披针形或条形; (5)萼片内面无毛是原始现象, 而被毛则是衍生现象; (6)萼片顶端无突起是原始现象, 出现突起则为衍生现象; (7)花药形状由长圆形演变到狭长圆形和条形。根据上述演化趋势, 推测具较多原始特征的甘川铁线莲C. akebioides和甘青铁线莲C. tangutica为此组的原始种, 而具较多衍生特征的尾尖铁线莲C. caudigera和角萼铁线莲C. corniculata为此组的进化种。组成世界屋脊的青藏高原西缘、帕米尔高原和邻近山地集中分布有此组10种(包括7特有种), 当是此组的分布中心; 而甘川铁线莲和甘青铁线莲二种分布区的主要重叠部分所在的青藏高原东缘则可能是此组的起源中心。过去,一些铁线莲属专家将属于欧洲铁线莲组的C. ispahanica Boiss.和属于对枝铁线莲组的C. graveolens Lindl.误置于黄花铁线莲组中, 对此, 本文予以纠正。

A revision of Clematis sect. Meclatis (Ranunculaceae)

Clematis sect. Meclatis is revised in this paper. Brief taxonomic history and geographical distribution of the section are given, its systematic position and the relationships among the species are discussed, and the evolutionary trends of some characters in the section are evaluated. Clematis akebioides (Maxim.) Veitch and C. tangutica (Maxim.) Korsh. are considered the primitive species in the section, whereas C. caudigera W. T. Wang and C. corniculata W. T. Wang are considered the advanced ones. The western edge of the Qinghai-Xizang (Tibet) plateau with the Pamirs and the adjacent mountains, the highest land mass in the world, where 10 species of the section are concentrated, is regarded as the distribution center, and the eastern edge of the Qinghai-Xizang (Tibet) plateau, where the two primitive species, C. akebioides and C. tangutica, sympatrically occur, may be the center of origin of the section. The inclusion of C. ispahanica Boiss. and C. graveolens Lindl. in sect. Meclatis by some authors is not accepted, with the former being a member of sect. Clematis, and the latter a member of sect. Brachiatae Snoeijer. A new variety, C. intricata Bunge var. intrapuberula W. T. Wang, is described, and two new combinations, C. tangutica var. mongolica (Grey-Wilson) W. T. Wang and C. tibetana Kuntze var. pamiralaica (Grey-Wilson) W. T. Wang, is proposed. As a result, 13 species and 13 varieties are recognized in sect. Meclatis. They are keyed, described, and illustrated.