Helianthus deserticola
Proc. Indiana Acad. Sci. 70: 209, fig. 1. 1960.
Annuals, 10–40 cm. Stems (green or red) erect, densely hirsute and glanddotted. Leaves mostly cauline; mostly alternate; petioles 1–6 cm; blades lanceolate to lanceovate, 2.5–5 × 1–2 cm, bases cuneate, margins entire, abaxial faces hispid-hirsute, densely glanddotted. Heads 1–5. Peduncles 1–3 (–8) cm. Involucres hemispheric, 13–25 mm diam. Phyllaries 13–21, lanceolate to lanceovate, 7–19 × 1.5–2 mm (equaling or slightly surpassing discs), (margins ciliate) apices acuminate, abaxial faces hispid (hairs erect, often 1+ mm) glanddotted. Paleae 8–9 mm, ± 3-toothed (middle teeth equaling or slightly surpassing discs, apices yellowish-brown, usually hispid). Ray-florets 7–13; laminae 10–30 mm (abaxial faces glanddotted). Disc-florets 25+; corollas 5.5–6 mm, lobes reddish; anthers dark, appendages purplish (style-branches reddish). Cypselae 4–5 mm, pilose; pappi usually of 2 linear scales 1.6–2.5 mm plus 4–6 linear or ovate, erose scales 0.5–1 mm. 2n = 34.
Phenology: Flowering spring–fall.
Habitat: Dry, open areas
Elevation: 400–1500 m
Distribution
Ariz., Nev., Utah.
Discussion
Helianthus deserticola is relatively uncommon; it is not federally listed. Abundant subsessile glands (“resin dots”) on stems, leaves, phyllaries, and abaxial faces of ray laminae help to distinguish H. deserticola from H. anomalus, with which it is sometimes lumped. L. H. Rieseberg (1991) demonstrated that it is of hybrid origin; parental species are H. annuus and H. petiolaris.
Selected References
None.