Flora of North America species comparison

Clarkia rubicunda is known from the central coast of California, from Contra Costa and Marin counties south along the coast and foothills to northern San Luis Obispo County.

Clarkia rubicunda is probably a derivative of C. amoena and may be ancestral to C. franciscana. Clarkia rubicunda is distinguishable from some populations of C. amoena only by the absence of a red spot or group of spots near the middle of the petal and the presence of a red area at the base of the petal. Clarkia rubicunda can be distinguished from C. franciscana by the position of the stigma and size and shape of the petals. All three species differ in chromosome arrangement and hybrids are highly sterile.

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

Clarkia lassenensis is found primarily in the northeastern counties of California, south-central counties of Oregon, and northwestern counties of Nevada, with a few outlier collections from Alpine and Placer counties in the Sierra Nevada, and from northern Mendocino and Glenn counties in the North Coast Ranges.

Clarkia lassenensis is morphologically most similar to C. arcuata and C. gracilis. At one time, C. lassenensis was considered a probable parent of the tetraploid C. gracilis but cytogenetic and molecular sequence data indicate that an unknown related species, presumably now extinct, was involved. Clarkia lassenensis can be distinguished readily from C. arcuata by flower size, position of the stigma, and pubescence of the immature capsule, and from C. gracilis by having immature capsules with eight grooves rather than four.

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