Publication: Vasc. Pl. Pacif. N.W. 5: 123, fig. [p. 125]. 1955.
selected vouchers: WTU
Notes: FNA21: "Chaenactis thompsonii appears to be sister to C. evermannii; it is known from the mountains of central and northwestern Washington. The similar habits of C. thompsonii and C. ramosa (= C. douglasii var. douglasii) appear to result from convergent evolution in the distinctive habitat of their type localities (Wenatchee Mountains), not from a close genetic relationship as suggested by Cronquist."