Flora of North America species comparison

Subspecies pallida occurs from the head of the San Joaquin Valley in Ventura and Kern counties, California, across the Colorado and Mojave deserts, north to the vicinity of Independence, Inyo County, California, and Esmeralda County, Nevada (the only member of the genus in Nevada), east to Mohave and Yavapai counties, Arizona, and also in the vicinity of Tucson, Pima County; also south along the eastern side of Baja California to the Sierra de San Borjas, Mexico.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera 21, species 582 (16 genera, 246 species in the flora).

Onagroideae encompass the main lineage of the family, after the early branching of Ludwigia (R. A. Levin et al. 2003, 2004). This large and diverse lineage is distinguished by the presence of a floral tube beyond the apex of the ovary; sepals deciduous with the floral tube, petals, and stamens; pollen shed in monads (or tetrads in Chylismia sect. Lignothera and all but one species of Epilobium); ovular vascular system exclusively transseptal (R. H. Eyde 1981); ovule archesporium multicellular (H. Tobe and P. H. Raven 1996); and change in base chromosome number from x = 8 in Ludwigia to x = 10 or x = 11 at the base of Onagroideae (Raven 1979; Levin et al. 2003). Molecular work (Levin et al. 2003, 2004) substantially supports the traditional tribal classification (P. A. Munz 1965; Raven 1979, 1988); tribes are recognized to delimit major branches within the phylogeny of Onagroideae, where the branches comprise strongly supported monophyletic groups of one or more genera.

(Discussion copyrighted by Flora of North America; reprinted with permission.)