Asclepias speciosa
Asclepiadaceae (Milkweed Family)

Foothills. Moist roadsides, fields. Summer.

"Asclepias" was a legendary Greek physician and the Greek god of medicine and "speciosa" is Latin for "showy or beautiful".

Linnaeus named this genus in 1753.  John Torrey named the species from a specimen collected by Edwin James in 1820 "on the Canadian [River]".  (Quotation from Intermountain Flora.)