Annuals, 10-60+ cm. Leaf blades lance-elliptic or oblanceolate to lance-linear, 25-50+ × 3-12+ mm, lengths 3-4(-6+) times widths, margins ± dentate or entire. Peduncles 4-30+ mm. Outer phyllaries 5, connate 0-¹/6 their lengths, ovate to elliptic, 4-6+ mm. Ray florets 7-12; corollas yellow, laminae oblong-elliptic, 1.2-1.5+ × 0.7-1+ mm. Disc florets 8-10+. Fruits 3-3.5+ mm. 2n = 60.

Flowering Aug-Oct. Sandy, gravelly, or loamy soils; 1200-1500 m; Ariz., N.Mex.; Mexico (Chihuahua, Sonora).

FNA 2006, Wiggins 1964, Kearney and Peebles 1969

Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Erect annual 10-40 cm tall moderately branched from near base, stems and branches spreading-hispidulous. Leaves: Oblanceolate to oblong-spatulate, 5-15 mm wide (without projecting lobes), 1.5-5 cm long, entire with 1-2 pairs of abruptly spreading lobes 3-9 mm long, cuneate toward sessile base, acute at apex, blade sparsely scabro-hispidulous. Flowers: Heads sessile or subsessile at tips of branchlets, subtended by leaves 3-6 times as long as heads, outer involucral bracts distinct, obovate, abruptly short-acuminate, sparsely hispid on midrib and along margins, 3.5-4 mm long; ray flowers inconspicuous, ligules 1-2 mm long or less, barely equaling or usually shorter than outer involucral bracts; disk flowers few, often only 3-5, inconspicuous. Fruits: Cypselae about 4 mm long, lightly but distinctly ridged, 3 low ridges on each lateral face and one fainter dorsal one, outer angles each bearing 1-3 low conical tuber-like swelling or projection, oblique cup, outer margin drawn into a recurvingly coiled, Ecology: Found in canyons, on hillsides, along streams, and often on limestone from 4,000-5,500 ft (1219-1676 m); flowers March-October.  Notes: Yellow ray flowers and the larger hooded fruit enveloping the achene set this plant apart from M. leucanthum. Also, pay attention to the curling involucral bracts. Ethnobotany: Unknown Etymology: Melampodium comes from Melampus, a soothsayer of renown in Greek mythology, while longicorne refers to the long spur, or hook on the fruit. Synonyms: None Editor: SBuckley, 2010