The morphology and affinities of Geranium sections Lucida and Unguiculata

Descriptions of the external morphology of six species of Geranium are presented to match those published by the author previously for the six species of the related sections Anemonifolia and Ruberta . It is proposed to merge Anemonifolia with Ruberta and to re‐define sections Lucida and Unguiculata , the first containing G. lucidum , G. glaberrimum and G. lasiopus , and the second G. macrorrhizum and G. dalmaticum , while G. cataractarum is placed in Ruberta . G. lasiopus is a plant of vertical and overhanging cliffs and has adaptations to keep the seeds within the habitat, whereas G. glaberrimum , from the same area of Turkey, occurs on step‐crevice and lacks these arrangements. For the species covered earlier, additional notes are provided for most, including reports on variation in G. robertianum in England, Taiwan and China. Attention is drawn to the informal term tangle‐strands for bundles of long clinging hairs borne by dormant stages of some plants and animals. Scanning electron micrographs of the mericarp surface of all 12 species and a list of specimen citations of interspecific hybrids are presented. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 409–429.