About Heterotheca sessiliflora (Nutt.) Shinners
Heterotheca sessiliflora, commonly called sessileflower false goldenaster, is a species of flowering plant in the family Asteraceae. It is native to California in the United States, and Sonora and Baja California in Mexico. This species grows in a wide range of habitat types. It is a perennial herb with very variable appearance, especially across its four accepted subspecies. Plants can grow as small clumping or mat-forming specimens, or produce tall stems that reach over one meter in height. The entire plant is covered in either small bristles or long woolly hairs, and is glandular, especially in the area around its inflorescence. Each flower head holds long yellowish disc florets at its center, and is fringed around the edge with yellow ray florets. This species has multiple recognized infraspecific taxa, with documented ranges as follows. Heterotheca sessiliflora subsp. bolanderi (A.Gray) Semple is found in the San Francisco Bay Area and the coast of Redwood Country. Heterotheca sessiliflora subsp. echioides (Benth.) Semple occurs from San Diego County north to Sonoma County. Heterotheca sessiliflora subsp. fastigiata (Greene) Semple is native to the mountains of southern California. There are two varieties and one additional subspecies: Heterotheca sessiliflora var. sessiliflora, Heterotheca sessiliflora subsp. sessiliflora ranges from Baja California north to Santa Clara County, and Heterotheca sessiliflora var. thiniicola (Rzed. & C.Ezcurra) G.L.Nesom is found in the Gran Desierto de Alta in northwestern Sonora.
