Sinosenecio nanchuanicus (Asteraceae), a New Species Small in Size Yet High in Chromosome Number from Chongqing, China

中國重慶產蒲兒根屬一體型小而染色體數目高的新種：南川蒲兒根

劉正宇(Zheng-Yu Liu) ； 劉瑩(Ying Liu) ； 楊親二(Qin-Er Yang)

《Botanical Studies》 52卷1期 (2011/01) Pp. 105-113

摘要

本文描述了中國重慶產蒲兒根屬一新種：南川蒲兒根(Sinosenecio nanchuanicus Z. Y. Liu, Y. Liu & Q. E. Yang)。其體細胞染色體數目為2n=144。本新種在體態，葉片圓形或近圓形，瘦果具冠毛方面與染色體數目為2n=48的滇黔蒲兒根(S. bodinieri (Vaniot) B. Nord.)最為相似，但除染色體數目不同外，還以植株較小，葉較小，葉片上表面深藍綠色，葉脈下陷，葉5-7規則淺裂，頭狀花序單生，舌狀花14-15而與後者相區別。本新種也以同樣的特徵以及葉片圓形或近圓形、邊緣具較長緣毛而與掌裂蒲兒根(S. palmatilobus (Kitam.) C. Jeffrey & Y. L. Chen)相區別。本文提供了南川蒲兒根以及滇黔蒲兒根和掌裂蒲兒根的彩色圖版和一些標本照片、南川蒲兒根的線繪圖、花部微觀性狀的光鏡照片以及地理分佈圖。

關鍵字

菊科 ； 染色體數目 ； 石灰岩植物區系 ； 地方特有現象 ； 多倍體 ； 千里光族 ； 南川蒲兒根

並列摘要

Sinosenecio nanchuanicus Z. Y. Liu, Y. Liu & Q. E. Yang, a new species of the Asteraceae from Chongqing, China, is described and illustrated. Its chromosome number (2n=144) is reported here. This new species is similar to S. bodinieri (Vaniot) B. Nord., a diploid species with 2n=48, in the posture, the rotundate or subrotundate leaf-lamina, the glabrous ovaries, and the pappose achenes, but differs in the smaller stature, the smaller leaf-lamina shallowly regularly 5-7-lobed and dark green above, the veins sunken above, the capitula constantly solitary and terminal, the rays 14-15, and the high chromosome number as well. From S. palmatilobus (Kitam.) C. Jeffrey & Y.L. Chen it differs also by these characters and, additionally, by its leaf-lamina rotundate or subrotundate in outline (vs. broadly ovate) and short-ciliate along the margin (vs. longciliate). All the taxa put in synonymies under S. bodinieri and S. palmatilobus were carefully re-examined and compared to S. nanchuanicus. Line drawings, distribution map, light microscope (LM) microphotographs of floral characters of S. nanchuanicus, color photographs of S. bodinieri, S. nanchuanicus and S. palmatilobus are provided.

並列關鍵字

Asteraceae ； Chromosome number ； Limestone flora ； Local endemism ； Polyploidy ； Senecioneae ； Sinosenecio nanchuanicus