The genus Geranium L. (Geraniaceae) in North America. II. Perennial species

Abstract

Perennial species of Geranium from North America north of Mexico are revised. Nineteen species are accepted, of which seventeen belong in subg. Geranium and two belong in subg. Robertium. Geranium erianthum, G. maculatum, G. oreganum, G. sylvaticum, G. caespitosum, G. californicum, G. lentum, G. wislizenii, G. richardsonii, G. viscosissimum are native, whereas G. pratense, G. sanguineum, G. potentilloides, G. sibiricum, G. thunbergii, G. retrorsum, G. solanderi, G. pyrenaicum and G. palmatum were introduced from Europe, Asia, and Oceania. Geranium eremophilum, G. fremontii, G. parryi, G. marginale and G. cowenii, sometimes accepted in current literature, are considered to be synonyms of G. caespitosum. Similarly, G. strigosum and G. attenuilobum are synonymized to G. viscosissimum, and G. concinnum to G. californicum. Nomenclature for all species is reviewed, and seventeen lectotypes are designated. Descriptions, key, distribution maps, and illustrations are included.