Pollen morphology of the subfamily Ehretioideae in the Boraginaceae from China and its systematic significance
中国紫草科厚壳树亚科的花粉形态及其系统学意义

Abstract: Pollen morphology in ten species of Ehretia and each one species in Rotula and Carmona of the Ehretioideae, Bora ginaceae, was observed under scanning electron microscope (SEM). Pollen grains are prolate or subspheroidal, rarely spheroidal, more