Annuals, 8-40+ cm. Stems mostly erect. Leaves all or mostly alternate (proximal sometimes opposite); blades simple or 1-2-ternately lobed, lobes filiform to linear, 5-12(-25+) × 0.5-1.5(-3+) mm, faces sparsely scabrellous, usually gland-dotted as well. Involucres 3-4+ × 6-9+ mm. Ray florets 8-13+; corolla laminae 3-4(-10+) mm. Disc florets 30-60+; corollas 2.5-3.5 mm. Cypselae 2-3+ mm, faces ± hirtellous; pappi of (outer cypselae) ± ovate to quadrate, apically ± muticous scales 0.5-1 mm or (innermost cypselae) lanceolate to lance-subulate, apically ± aristate scales 1-2.5 mm.
Flowering (May-)Sep-Oct. Granite outcrops; 1200-1600 m; Ariz., N.Mex.
FNA 2006, Wiggins 1964, Kearney and Peebles 1969
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Annual with erect stems 8-40 cm with cinereous-puberulent stems and foliage. Leaves: Mostly or all alternate, blades simple or 1-2 ternately lobed, lobes filiform to linear 5-12 mm long by 0.5-1.5 mm wide, faces sparsely scabrellous, usually gland-dotted on petioles much shorter than blade. Flowers: Corymbose, on peduncle 4-5 cm long, involucre 3-4 mm high, 6-9 cm wide, hemispheric; ray florets 8-13, bright yellow, with corolla laminae 3-4 mm; 30-60 disc florets, corollas 2.5-3.5 mm, throat narrowly campanulate. Fruits: Cypselae 2-3 mm, faces hirtellous, 4-angled, narrowly obpyramidal, strongly striate and hirsute, pappus of 12-14 obovate squamellate. Ecology: Found along arroyos and watercourses and on brushy or forested hillsides, in some instances on granite outcrops from 1,000-4,500 ft (305-1372 m); flowers May-October. Notes: Distinguished by its alternate leaves, annual habit, with leaf lobes that are filiform to linear. Ethnobotany: Unknown, but other species in the genus have uses. Etymology: Bahia is named after Juan Francisco de Bahi y Fonseca (1775-1841), a Spanish botany professor, while biternata comes from bi, for two, and ternata meaning with parts in groups of threes, often the leaflets, which would be doubly in threes. Synonyms: None Editor: SBuckley, 2010