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The cytotaxonomy and origin ofRanunculus yaegatakensis, an endemic taxon of Yakushima Island

1990; Botanical Society of Japan; Volume: 103; Issue: 1 Linguagem: Inglês

10.1007/bf02488410

2185-3835

Hirosumi Fujishima, Hiroshi Okada, Yukie Horio, Tetsukazu Yahara,

Botany, Ecology, and Taxonomy Studies

Ranunculus yaegatakensis, a close relative of the widespreadR. silerifolius, is endemic to the alpine region (ca. 1,600 m alt.) of Yakushima Island. This species differs morphologically fromRanunculus silerifolius mainly due to its dwarfism and leaf shape, but has an identical karyotype with one (Karatsu-type) of the four cytotype ofR. silerifolius. Ranunculus yaegatakensis is highly cross-compatible with the Karatsu-type plants ofR. silerifolius. Their F1 hybrids show regular meiotic behaviors and set seeds successfully. In addition, the Karatsu-type ofRanunculus silerifolius is found in individuals that are collected not only from the lowland of Yakushima Island but from its neighboring islands. It is supposed to be more specialized than other cytotypes. This evidence suggests thatRanunculus yaegatakensis has been derived from the Karatsu-type plants ofR. silerifolius. We suggest thatRanunculus yaegatakensis be reduced to a variety ofR. silerifolius.