Comparative Observation on Venation about Four Genera in Cruciferae

The comparative observation on leaf venation in 16 species belong to Cochlearia,Yinshania,Hilliella and Cochleariella were conducted.The rusult shows:Venation of Cochlearia is Brochidodromous;Hilliella is Craspedodromous,Yinshania is Half-Craspedodromous and Cochleariella is similar to H. warburgii.The fomer three genera have differences in size of areole,marginal ultimate venation and shape of apex.It is reasonable for the fomer three genera to exist.The taxonomy position of Cochleariella is merit study further.The evolution relationship of venation for these genera is Basal Perfect Actinodromous→Brochidodromous→Craspedodromous.