Verbesina rothrockii

Plants 30-60+ cm (perennating bases ± erect, internodes not winged). Leaves all or mostly opposite (distal sometimes alternate); blades ovate-deltate or rhombic to lance-elliptic, 3-5 × 1-3 cm, bases subtruncate to cuneate, margins coarsely toothed to subentire, apices obtuse to acute, faces ± hirtellous to scabrellous. Heads borne singly. Involucres ± hemispheric, 10-15+ mm diam. Phyllaries 18-30+ in 3-4 series, ± erect, oblong to elliptic, 6-10+ mm. Ray florets 8-13; laminae 15-25+ mm. Disc florets 60-100+; corollas yellow. Cypselae dark brown, ± elliptic, 10 mm, faces glabrous; pappi 0-0.5 mm. 2n = 34.

Flowering (May-)Aug-Sep. Rocky slopes, igneous or limestone substrates; 1200-1800 m; Ariz., N.Mex.; Mexico (Coahuila, Durango, Zacatecas).

FNA 2006, Martin and Hutchings 1980

Duration: Perennial Nativity: Native Lifeform: Forb/Herb General: Perennial with erect stems, simple or few-branched 30-60 cm tall, herbage scabrous-hispidulous. Leaves: All or mostly opposite, upper ones rarely alternate, sessile, thick, ovate-deltate or rhombic to lance-elliptic blades, 3-5 cm long by 1-3 cm wide, bases subtruncate to cuneate, margins coarsely toothed to subentire, apices obtuse to acute, faces hirtellous to scabrellous. Flowers: Heads borne singly or on long naked peduncles, with hemispheric involucres 10-15 mm in diameter; phyllaries 18-30 in 3-4 series, erect, oblong to elliptic, 6-10 mm; ray florets yellow, pistillate 8-13, laminate 15-25 mm; disc florets 60-100, yellow. Fruits: Cypselae dark brown, elliptic, 10 mm, faces glabrous, with pappus 0-0.5 mm. Ecology: Found on rocky slopes, often on igneous or limestone soils from 4,000-6,000 ft (1219-1829 m); flowers June-September. Distribution: s AZ, sw NM; south to n MEX. Notes: Distinguished by its opposite leaves, 10-15 mm diameter involucres and elliptic to oblong phyllaries. Promptly loses its rays leaving globose heads; resembles Acourtia vegetatively but has larger heads and leaves with wider-spaced teeth and without marginal hairs. Ethnobotany: Unknown, but other species in the genus have uses. Etymology: Verbesina is derived from Verbena, while rothrockii is named for Dr. Joseph Trimble Rothrock (1839-1922), surgeon on the Wheeler expedition of 1873-1875. Synonyms: None Editor: SBuckley 2010, FSCoburn 2015