Annuals, 10-80+ cm. Stems erect. Leaves opposite (proximal) and alternate; petioles 5-15(-25+) mm; blades ± deltate, 15-40(-85+) × 12-35(-80+) mm, 1-2-pinnately lobed, bases cuneate, ultimate margins entire or toothed, abaxial faces hispid and strigillose to sericeous, adaxial faces strigillose and gland-dotted. Pistillate heads clustered, proximal to staminates; florets 1. Staminate heads: peduncles 0.5-2 mm; involucres shallowly cup-shaped (usually each with 1-5+ black nerves), 3-5(-7) mm diam., sparsely hirsute or glabrous; florets 6-12(-20+). Burs: bodies fusiform to obpyramidal, 3-5 mm, ± hirsutulous or glabrate, spines 8-18+, scattered, stoutly subulate (sometimes basally flattened or navicular), 2-4(-5) mm, tips straight or uncinate. 2n = 36. Flowering (Apr-)Jul-Nov. Canyons, sandy flats, dunes; 10-3000 m; Alta., Man., Sask.; Ariz., Calif., Colo., Idaho, Kans., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Okla., Oreg., S.Dak., Tex., Utah, Wash., Wyo.

Plant: Annual 4-15 dm, from slender taproot; monoecious; stem gray-green, ± stiffly strigose-bristly Leaves: opposite below, generally alternate above; petioles winged; blade pinnately divided, < 8 cm, 7 cm wide INFLORESCENCE: inflorescence a head, each resembling a flower; staminate heads generally many in ± spikes or racemes, 2-5 mm diam, involucre lobes 3-9, tips of longest 3 ± black-lined along midveins; phyllaries fused into shallow cup; pistillate heads 1-flowered, below staminate, generally spiny, bur-like; involucre ± 0; receptacle chaffy; chaff scales spirally arrayed, fused below, tips generally becoming spiny; each pistillate flower in separate chamber Flowers: Staminate flowers ± many; corolla yellow or translucent; anthers free; style unbranched; Pistillate flowers 1-5; corolla 0; style branches long Fruit: Fruit: enclose bur 5-7 mm, ovoid, generally ± golden, glabrous or puberulent; spines 0-30, scattered, flat, straight, sharp; pappus 0 Misc: Sandy plains, disturbed sites, many communities; < 2200 m.; Aug-Nov References: AZ Flora: Kearney and Peebles, Seed Plants of N. AZ: McDougall, The Jepson Manual: Hickman, ASU Specimens