WU Ding, WANG Hong, LU Jin-Mei, LI De-Zhu
J Syst Evol. 2005, 43(3): 210-224.
Epidermal characters of mature leaves in 30 species representing all the nine sections of Parnassia (Parnassiaceae) were investigated under both light microscope (LM) and scanning electron microscope (SEM). The stomata were anomocytic and existed on abaxial epidermis in all the species examined, and on the adaxial epidermis in some species. The leaf epidermal cells were usually irregular or polygonal in shape. The patterns of anticlinal walls were slightly straight, repand or sinuate. Under SEM, the inner margin of the outer stomatal rim was nearly smooth, sinuolate or sinuous, and the cuticular membrane of the leaf epidermis was striate, sometimes striate to wrinkled, occasionally granular or foveolate. Stomatal and other epidermal features in Parnassia appear to be constant within species, and thus can be used for distinguishing some species. Leaf epidermal features show that Parnassia is a quite natural genus. The previous reports that the stomata are anomocytic and occur only abaxially in Parnassia, yet occur both adaxially and abaxially in Lepuropetalon are not confirmed by this study, which, based on more extensive study, has shown that some species of Parnassia also exhibited stomata on both adaxial and abaxial sides. Evidence from leaf epidermis, together with that from floral anatomy and pollen morphology as well as biogeography, suggests that section Saxifragastrum may be heterogeneous. Parnassia delavayi should be treated as a section of its own, i.e. section Xiphosandra based on morphological, cytological and leaf epidermal data.
