大吴风草属、假橐吾属花粉表面纹饰及其分类学意义

The pollen characteristics under SEM in Farfugium and Ligulariopsis and their taxonomic significane

观察了千里光族款冬亚族中大吴风草属、假橐吾属及其相关类群 5属共 8种植物在扫描电镜下的花粉性状。所有种类的花粉外壁均为刺状纹饰 ,但在刺的长短、刺部是否膨大、刺基膨大上的纹饰以及刺基之间的纹饰等方面存在差别。大吴风草的花粉外壁性状不同于橐吾属 ,从而不支持它与后者有较近亲缘关系的观点 ;它与花粉超薄结构同为“向日葵型”的多榔菊属的花粉外壁性状也不相同。假橐吾属不同于橐吾属和垂头菊属的花粉外壁性状 。

Observed in the present paper are the pollen characteristics under SEM of 8 species in Farfugium,Ligulariopsis and related taxa in the Senecioneae.The pollen grains in all taxa investigated have spiny exine ornamentation.However,among the \{taxa\},the length of spines,the base of spines and the interspiny ornametation still show a great variation.As revealed in the present observation,the exine ornamentation of Farfugium differs greatly with that of Ligularia ;and the result do not support the viewpoint that two genera are closely correlated to.Furthermore,the exine ornamentation of Farfugium is also different with that of Doronicum although both genera commonly share the 'Helianthoid' type pollen wall ultrastructure in the Senecioneae.The exine ornamentation of Ligulariopsis is distinctly different from that of Ligularia and Cremanthodium and the result supports the establishment of the monotypic genus Ligulariopsis .