282. Encelia Adanson, Fam. Pl. 2: 128. 1763.
[For Christoph Entzelt (Christophorus Enzelius), 1517–1583, German naturalist]
Curtis Clark
Perennials, subshrubs, or shrubs (10–)30–150 cm. Stems erect, usually branched from bases, often throughout (scapiform in E. nutans and E. scaposa). Leaves usually cauline, sometimes basal (E. nutans and E. scaposa); alternate (usually drought-deciduous); petiolate (obscurely in E. scaposa); blades (1- or 3-nerved) mostly deltate, lanceolate, rhombic, or ovate (narrowly oblanceolate to linear in E. scaposa), bases broadly to narrowly cuneate, margins usually entire, rarely toothed, face glabrous or canescent, hirtellous, scabrellous, strigose, or tomentose, often gland-dotted as well. Heads radiate or discoid, borne singly or in ± paniculiform arrays (peduncles usually longer than involucres). Involucres ± hemispheric or broader, 4–22 mm diam. Phyllaries persistent, 18–30(–50+) in 2–3+ series (subequal to unequal, outer shorter). Receptacles flat or convex, paleate (paleae ± conduplicate, folded around and falling with cypselae). Ray florets 0 or 8–25(–40), neuter; corollas yellow. Disc florets 80–100(–200+), bisexual, fertile; corollas yellow or brown-purple, tubes shorter than to equaling abruptly expanded throats, lobes 5, triangular. Cypselae strongly compressed, obovate to cuneate (margins ciliate, apices usually ± notched except in E. scaposa, faces usually glabrous except in E. scaposa); pappi usually 0, sometimes readily falling or persistent, of 2 bristlelike awns. x = 18.
Species 13 or 14 (8 in the flora): sw United States, Mexico, South America.
Encelias commonly hybridize, especially in disturbed areas: Encelia farinosa × E. frutescens is common; E. farinosa × E. californica, E. farinosa × E. actoni, E. actoni × E. frutescens, E. frutescens × E. virginensis, and E. farinosa × Geraea canescens have been reported.
SELECTED REFERENCE
Clark, C. 1998. Phylogeny and adaptation in the Encelia alliance (Asteraceae: Heliantheae). Aliso 17: 89–98.
