Taxonomic Revision of Geranium sect. Ruberta and Unguiculata (Geraniaceae)
Geranium L. sect. Ruberta Dumort. and section Unguiculata (Boiss.) Reiche (Geraniaceae) consists of 10 and two species, respectively. The highest diversity of section Ruberta is located in Macaronesia with seven species, four of them endemic. Additionally, two species are endemic to Turkey, another is restricted to southern Spain and Morocco, and three are naturalized in many temperate regions of the world but are native to Europe and adjacent areas of Africa and western Asia. Section Unguiculata is mainly found on the Balkan Peninsula, although one species reaches eastward to the mountains of southern France. Geranium sect. Ruberta is characterized by its actinomorphic flowers (only G. palmatum Cav. has slightly zygomorphic flowers) and its petals with a bicarinate and well-developed claw. This broader concept of the section Ruberta, which includes section Lucida R. Knuth, permits the unequivocal inclusion of all species, unlike the previous proposal to separate these species into two sections. The species of section Unguiculata are characterized by the clearly zygomorphic flowers and petals with a smooth claw. In contrast with some regional treatments, I have synonymized G. eginense Hausskn. & Sint. ex R. Knuth and G. elamellatum Kokwaro to G. purpureum Vill. and G. kikianum Kit Tan & Vold to G. macrorrhizum L. A new key is provided as well as new and detailed descriptions. Each species is illustrated and mapped, and 43 lectotypes and three neotypes are designated.