notes The plants here were growing in serpentine-derived soil on an east-facing roadcut a few miles north of the Parkfield Grade summit.
Using the Jepson eFlora Key to Trifolium these plants go to Trifolium dichotomum...which (in 2010) was promoted to species level from prior varietal status as T. albopurpureum var. dichotomum in the 1993 Jepson Manual treatment (see note here).
However, naturalist Randall Morgan...having spent many years working on Trifolium: combining perceptive and meticulous observations from extensive field work; countless growing experiments; the literature; and (with a collaborator) molecular analysis...has arrived at a circumscription of CA Trifolium that sometimes differs from the current Jepson treatment, recognizing a number of both new, as well as resurrected, taxa.
Randy showed me the plants photographed here, and explained that they represent a fairly rare species that, based on morphology and DNA analysis, he would place under the old name T. pseudoalbopurpureum Kennedy (genotype B). You can find Kennedy's original 1913 description of T. pseudo-albopurpureum here, and a specimen sheet is shown here.
The question of what name to post these images under poses a dilemma. On the one hand, I am aware of Randy's unique gifts as a master botanist...and have good reason to believe that few if any people have the depth of knowledge, experience, and understanding of Trifolium that he has developed (especially for the California taxa)...and thus I put great value in the integrity of his taxonomic reasoning and assessments. On the other hand, the Jepson eFlora currently provides the defacto standard for conventional name usage among California botanists. Also, the ''details'' page for any CalPhotos post uses the name deemed valid on the Jepson Interchange to configure a host of subsidiary links (e.g. to the Jepson eFlora, CalFlora, Tropicos, other CalPhotos posts, etc.). And no recent publication has put forth the reasoning or fulfilled the procedural requirements for giving formal status to the name T. pseudoalbopurpureum here. Both Tropicos and The Plant List presently treat T. pseudoalbopurpureum as a junior synonym of T. albopurpureum.
Alas, it's a well-known fact that disagreements often occur regarding taxonomic circumscriptions and assignments. My practical compromise is to make CalPhotos posts under the name currently used by the Jepson eFlora, but promote and try to provide supporting information for deserving alternative circumscriptions...hoping that eventually the (significant!) hurdles to formally promulgating improved circumscriptions will occur, and lead to better understanding.