Publication: Corrig. 1927.
selected vouchers: WTU
Notes: FNA8: "Johnson placed Saxifraga nuttallii in his monotypic genus Cascadia based on the unusual habit, free carpels, and spiny seeds. Molecular phylogenetic data (M. E. Mort and D. E. Soltis 1999; Soltis et al. 2001) placed Cascadia as sister to the southern South American (Tierra del Fuego) Saxifragodes D. M. Moore, both sister to Micranthes. Mort and Soltis considered the ovary of Cascadia to be superior because the two carpels are distinct to their bases; the hypanthium, fused to each carpel, gives the ovaries a semi-inferior appearance. Ovules in Cascadia are bitegmic, as in Saxifraga; those of Micranthes are usually unitegmic.
Cascadia nuttallii is found from the coastal mountains to the western slopes of the Cascade Range, from extreme northwestern California to southwestern Washington. The accepted species name was validated in a correction slip attached to reprints of Johnson's article describing Cascadia."