Flora of North America species comparison

Clarkia stellata is known from the southern Cascade–northern Sierra Nevada region, including Lassen, Nevada, Plumas, Shasta, Sierra, and Tehama counties (with unverified reports from Butte and Modoc counties).

Clarkia stellata is probably a self-pollinating derivative of C. mildrediae subsp. lutescens, to judge from pollen color. The two species are readily distinguishedby the much smaller flowers of C. stellata and the position of the stigma. Hybrids have low fertility due to chromosomal rearrangement. Clarkia stellata is morphologically very similar to the self-pollinating tetraploid C. rhomboidea but can be distinguished from it by yellow pollen and shallowly lobed, unspotted petals.

(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.)