Morphological features of leaf epidermis of 30 Tectariaceae species

The epidermal morphology of 30 species of Tectariaceae was investigated via light microscopy. Results indicated that: (1) The shapes of the upper and lower epidermal cells of all 30 species were irregular, with sinuate or repand anticlinal walls. Monocrystals or needle crystals were observed in the epidermal cells. The length-to-width radios of the upper and lower epidermal cells were between 1.62-4.0 and 1.63-3.06 respectively. (2) In the 30 species, seven stomatal apparatus types, i.e. polocytic, axillocytic, copolocytic, coaxillocytic, aisocytic, anomotetracytic, and anomocytic types, were observed. Each plant had four to seven types, and all stomatal apparatuses occurred in the lower epidermis. The stomatal length-to-width ratio was 1.22 - 1.91; stomatal density was 8 - 76 mm²; and stomatal index was 3.9%-25.7%. (3) Based on cluster analysis of the stomatal apparatus types, the 30 species could be divided into three groups. (4) From the morphological characteristics of the leaf epidermis, we concluded that the genus Ctenitopsis lies between Tectaria and Ctenitis, and is more closely related to the former. Thus, the scope of the genus Tectaria needs further study. Our results support the isolation of Ctenitis from the family Tectariaceae and its placement in the family Dryopteridaceae, but not the placement of Pleocnemia in Dryopteridaceae.