[Studies on the leaf epidermal features of Lepidium (Brassicaceae) from China].

Objective: Classification and diagnostic study on Lepidiumn (Brassicaceae) from China.
Methods: Leaf epidermal mi-cromophology of 10 species of Lepidium from China were observed by using LM (light microscope) and SEM (scaning electron microscope).
Results: The stomatal apparatuses present both on the adaxial epidermis and the abaxial epidermis. The type of stomatal apparatuses is mainly anisocytic, rarely anomocytic and only occasionally paracytic. The leaf epidermal cells of Lepidium are usually irregular or polygonal in shape. The patterns of anticlinal walls are straight, arched, sinuolate or sinuous. The leaf features of Lepidium have better consistency. The morphology of the upper epidermis and the lower epidermis is similar, and with simple trichomes or glabrous on the leaf surface. Under SEM observation, the inner margin of the outer stomatal rim is nearly smooth or sinuolate, and the cuticular membrane of the leaf epidermis is striate. The shapes of leaf epidermal cells, the patterns of anticlinal walls, the types of stomatal ap-paratuses, the stomatal index, the stomatal size and the characters of the cuticular membrane of the leaf epidermis have important reference for differentiating species of Lepidium.
Conclusion: The leaf epidermal features can serve as a criterion of distinguishing species in the genus Lepidium (Brassicaceae) from China, and also provide new evidence for rational use and exploitation of medical resources in Lepidium.