Leaf blades mostly 10-30, 8-25 cm, distal smaller. Heads 10-100+ together. Cypselae obovoid, somewhat cucullate, 1.8-2 mm, often tuberculate, glabrous. 2n = 36.

Flowering mostly summer. Desert slopes, washes, southern exposures; 900-1400 m; Ariz.; Mexico (Baja California Sur, Chihuahua, Sinaloa, Sonora).

Duration: Annual

Nativity: Native

Lifeform: Forb/Herb

General: Moderately to profusely branched herb to 2 m tall.

Leaves: Ample, blades lance-ovate to broadly ovate-cordate, 1-15 cm broad, 3-20 cm long, upper smaller ones entire, larger coarsely and irregularly dentate, bright green and sparsely puberulent to glabrate above, paler and more densely puberulent beneath; petioles to 10 cm long, blades decurrent on upper portion.

Flowers: Panicles 10-40 cm long, involucres 4-5 mm in diameter at anthesis; bracts obtuse or rounded, thin, densely short-puberulent and somewhat scurfy; corollas of sterile disk flowers 1-1.3 mm long, tube very short, abruptly expanding into narrowly funnelform throat, lobes minute, densely cobwebby with hairs of adjacent corollas intertangled; corollas of pistillate flowers tubular, about 0.3 mm long or less.

Fruits: Cypselae 1-1.3 mm long, ovoid, compressed, attached to and falling with paleae of 2 disk flowers immediately adjacent.

Ecology: Found along watercourses, hillsides, and mesas from 3,500-5,000 ft (1067-1524 m); flowers February-September.

Notes: Endemic to Arizona. Very unique in appearance, with stalks to 5 cm in diameter, or larger. Odd flowers; plant appears to be farinose.

Ethnobotany: Unknown

Etymology: Parthenice alludes to members of the genus Parthenium, mollis means soft or with soft velvety hair.

Synonyms: None

Editor: SBuckley, 2010