The entity of Carex persistens var. watanabei (Cyperaceae)

Abstract

Carex persistens Ohwi var. watanabei Ohwi was described in "New Flora of Japan" (Ohwi & Kitagawa 1983) on the basis of the material from Fukui Pref. with perigynia patently hairy. This name is, however, nomenclaturally invalid because the Latin description was not given in the protologue. In order to clarify whether this variety is acceptable as a taxon, we examined its original material and many herbarium specimens of related taxa, C. persistens including var. takeuchii Ohwi, and also made field survey. The result showed that hair density on perigynia continuously varied from glabrous to densely setaceous. The glabrous form had the widest distribution range, and the forms with more hairy perigynia were restricted in the northern Kinki district and Fukui Pref. However, even in the area where the hairy forms are distributed, the glabrous form is commonly found, and any ecological differences were not detected in their habitat. Therefore we concluded that C. persistens should be treated as a variable species without recognizing any infraspecific taxa based on the hairiness of perigynia such as var. takeuchii or var. watanabei.