Abstract

Abstract: The pollen morphology of 12 genera and 34 species belonging to the Desmodieae in Taiwan was studies by light microscope, scanning electron microscope and transmission electron microscope. The great variation in pollen characteristics among these plants was examined. According to pollen morphology and extine stratification, the pollen grains can be divided into six types. (I)The tectum is coarsely reticulate and distinctly marginate on colpial margins. It has operculum-like structure. The simple columellae have no granular interstitium. (II) This type is divided into two subtypes. (a) The tectum is finely reticulate, marginate and microperforated; the colpus membrane is finey granulate; and the foot layer is reduced. (b)The tectum is reticulate, and it has no microchannel and granular interstitium. The endexine is thicker than the tectum.(III) The tectum is coarsely verrucate or weakly regulate. Only the pollen of Alysicarpus sp. has mesocolpial pouches partially covering the endoapertures.(IV) The tectum is microperforated or weakly regulate; and the foot layer is discontinuous and reduced. (V) The tectum is finely reticulate; the foot layer is thin and discontinuous. (VI) The tectum is microperforated; the columellae are replaced by granular interstitium; and there is no foot layer.

中文摘要

本文以台灣山螞蝗族(Demodieae) 中十二個屬三十四種植物的花粉為材料，應用光學及電子顯微鏡來觀察花粉外佈型態及內部層次構造中所展現的特徵差異，這一族植物的花粉型態變異很大，雖然都是三溝孔粉，但外壁花紋及層次結構在種與種之間卻各異其趣。 山螞蝗族植物之花粉依目前所觀察的結果，由外部型態及層次結構將其分為六個類型。第一類型：外壁粗網紋，明顯雙緣溝，具孔蓋似的構造，單純的圓柱層並無孔間顆粒存在。第二類型又分兩種亞型：A外壁皆有粗網紋，雙緣溝，溝緣外壁雕紋微細穿孔，溝孔處有細顆粒覆蓋，基層則逐漸消退﹔B外壁細網紋，壁層沒有微細管道及柱間顆粒，最內層厚度大增。第三類型：外壁具粗瘤狀突起，蓋頂明顯半圓紋。第四類型：外壁微細穿孔或具有輕微網狀散條紋，基層不連續或逐漸消退。第五類型：外壁皆細網紋，基層不連續，最內層厚度與蓋頂相當。第六類型：外壁具微細穿孔，圓柱層被柱間顆粒取代，基層消失。 分類學者比較各屬間之外部型態，將山螞蝗族又分三個亞族，台灣僅產兩個亞族即螞蝗亞族及胡枝子亞族，但是由花粉型態上的差異來看，反在其間尋到一些相似性，可能是演化的過程中適應環境而在外部型態上產生變化，內部構造如花粉粒卻未及改變而保持相似的特徵。