Article

In order to assess the taxonomic significance of the epidermal structure, seven taxa from genus Cyanus Mill. (sect. Napuliferae) have been studied: Cyanus pseudaxillaris, C. orbelicus, C. velenovskyi, C. napulifer, C. nyssanus, C. tuberosus and C. thirkei. The investigated taxa possess thick covering of trichomes. The hairs consist of two or more basal cells (stalk) and a long whip cell. Five types of trichomes, very well distinguished by the number, form, size and the wall thickening of the stalk, were established. The cuticle is thin and easily could be distorted under gentle maceration. Some taxa possess cuticle corrugations, somewhere parallel to long cell axis. There are striations on the whole cuticle or only around the stomata and the trichome bases. The main stomatal type is anomocytic, but there are some stomata from anisocytic type, frequently untypical: the three cells do not encircle the stoma. There are stomata with only one subsidiary cell, which is rounded, smaller and well distinguishable by the other epidermal cells. The comparative study shows the epidermal features possess taxonomic significance and could be used as additional characters to differentiate the species into sect. Napuliferae of genus Cyanus.