Abstract
Ranunculusluanchuanensis (Ranunculaceae), a new species from Laojun Shan in Luanchuan county, Henan province, central China, is here illustrated and described. It is morphologically similar to R.limprichtii in having 3-lobed and subreniform basal leaves, 3-lobed cauline leaves, and small flowers with reflexed and caducous sepals, but differs by having slender and basally slightly thickened roots (vs. fusiform), prostrate stems (vs. erect), obliquely ovoid and glabrous carpels and achenes (vs. widely ovoid and puberulous), longer styles in the carpels (ca. 1.2 mm vs. 0.6-0.8 mm) and achenes (ca. 1.8 mm vs. 0.6-0.8 mm), and glabrous receptacles (vs. sparsely puberulous). Ranunculusluanchuanensis, currently known only from its type locality, is geographically isolated from R.limprichtii, a species widely distributed in Gansu, Qinghai, Sichuan, Xizang (Tibet) and Yunnan, China. The distribution map of this new species and its putative closest ally, R.limprichtii, is also provided.