Flora of North America species comparison

Clarkia epilobioides is known from south-central Arizona in Gila, Maricopa, Pima, and Pinal counties, and widely in west-central and southwestern California and adjacent Baja California, Mexico. In California, it occurs from Contra Costa and San Mateo counties in the San Francisco Bay area to San Diego County in the south, including most of the Channel Islands.

Clarkia epilobioides is modally self-pollinating, and up to half of its flowers do not open, yet set a full complement of seeds (H. Lewis and M. E. Lewis 1955). However, outcrossing does occur, and C. epilobioides is one of the parents of the tetraploid species C. similis, from which it differs by having white, unflecked petals; it is also one of the parents of the tetraploid C. delicata.

(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.)