Abstract:The epidermal structure of leaves of Cordaites schenkii Halle is described. The specimens of C. schenkii were collected from the roof of Coal No. 9 in lower part of Taiyuan Formation, Pinglu-Shuoxian Coal-Field, Shanxi Province, North China. The age of plant fossil bearing strata is considered as Stephanian, Late Carboniferous.
Main feattures of the epidermal structure of Cordaites schenkii Halle: Upper cuticle is a little thinner than the lower one and there are few of stomata on the upper epidermis. The lower epidermis consists of alternating stomatiferous and non-stomatiferous bands. There are 1-6( mainly 2-5) rows of epidermal cells in non-stomatiferous bands. Only one stomata row in each stomatiferous band. Each stomatal apparatus has two sunken guard cells, two lateral and
two polar subsidiary cells. Usually a single polar subsidiary cell is common to two consecutive stomata, although it is not unusual that each stomatal apparatus has its own polar subsidiary cells. There are 1-3 ( mainly 1-2) papillous cuticular thickenings on the center of each epidermal cell and lateral subsidiary cell. Moreover, there are strongly developed papillous cuticular thickenings arround the stomatal openings on both lateral and polar subsidiary cells. The
lower epidermis has an average stomatal frequency of 269/mm2.
Comparisons on the epidermal structure of C. schenkii with other species of Cordaites from Cathaysian and Euramerican Flora suggest that C. schenkii is very different from the latter.