螺序草属(茜草科)的花粉形态

首次对螺序草属(Spiradiclis B1.)的11种和1变型共16份植物的花粉样品在光镜和电镜下进行了观察。结果表明，本属植物花粉为单粒，小型和中型花粉，近球形至椭球形，辐射对称，常具3孔沟，偶为4孔沟，外壁表面纹饰为孔状。花粉外壁由不连续的具穿孔的覆盖层、柱状结构和基层组成，内外壁明显。此外，本属植物的花粉具有花粉2型和“芽状”结构的现象。螺序草属植物的花粉形态在属下分类上有一定的局限性，但是在个体的系统发育上却可以提供极有价值的信息，如具有花粉单型的种类比花粉二型的种类进化。

Pollen Morphology of Spiradiclis Bl. (Rubiaceae)

Sixteen pollen samples from 11 species and 1 form of the genus Spiradiclis Bl. were examined under LM, SEM and TEM . Results revealed that pollen grains of Spiradiclis were single, small or medium-sized, spheroidal to prolate, radial symmetry, usually 3-colporate, sometimes 4-colporate, and with perforated tectate. The exine consisted of inconsistent perforated tectate, columellae and foot layer. Both exine and intine wereobvious. Pollen dimorphism and bubble-like protrusions were found in Spiradiclis. Pollen characters of Spiradiclis have little value for distinguishing infra-genus taxa, but they can provide much information in the phylogeneticrelationships among species, e.g., the taxon having same pollen is more advanced than that having dimorphic pollen.