Shrubs, 30-100 cm (branched from bases). Stems erect to ascending, slender, striate-angled, glabrous, resinous. Leaves present at flowering; short-petiolate; blades (1- or obscurely 3-nerved) obovate to oblanceolate, 20-35 × 3-15 mm, distally reduced and narrowed, bases cuneate, margins irregularly incised to coarsely serrate or 2-serrate, faces glabrous, gland-dotted, resinous. Heads (20-50) in corymbiform arrays. Involucres campanulate; staminate 4-5 mm, pistillate 4-5 mm. Phyllaries lanceolate, 1-4 mm, margins scarious, medians green, apices acute, erose. Staminate florets 15-20; corollas 3.5-4 mm. Pistillate florets 25-30; corollas 2-2.6 mm. Cypselae 1.5-2.2 mm, 5-nerved, glabrous; pappi 3-4.5 mm. Flowering Aug-Nov. Dry rocky ground in coniferous forests; 1300-2000 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua , Durango, Sonora ). Baccharis bigelovii occurs in the general Chihuahuan Desert region in the Davis Mountains of West Texas, and in the Chiricahua and Huachuca mountains of Arizona. It is recognized by the relatively short stature, obovate, coarsely and irregularly serrate leaves, erose-ciliate phyllaries, and 5-nerved cypselae. It is similar to B. thesioides, which differs mainly by having narrower, more oblong leaves with more evenly serrate margins and spinulose teeth. Further investigation may show these two taxa to be different geographic expressions of a single species centered in Mexico.
FNA 2008, Kearney and Peebles 1969
Common Name: Bigelow's false willow Duration: Perennial Nativity: Native Lifeform: Subshrub General: Shrub with slender, erect to ascending stems 30-100 cm, glabrous, resinous, striate-angled. Leaves: Short-petiolate, blades obovate to oblanceolate, 20-35 by 3-15 mm, distally reduced and narrowed, bases cuneate, margins irregularly incised to coarsely serrate or 2-serrate, faces glabrous. Flowers: In corymbiform arrays, campanulate involucres, staminate 4-5 mm, pisttillate 4-5 mm; lanceolate phyllaries 1-4 mm, scarious margins, green medians, acute apices, erose; corollas 3.5-4 mm. Fruits: Cypselae 1.5-2.2 mm, 5 nerved, glabrous, pappus 3-4.5 mm. Ecology: Found on dry rocky ground from 4,500-6,000 ft (1372-1829 m); flowers August-November. Notes: FNA notes that B. bigelovii is distinguished by its short stature, obovate, coarsely and irregularly serrate leaves, erose-ciliate phyllaries and 5-nerved cypselae. Similar to B. thesioides, which differs having narrower, more oblong leaves with more evenly serrate margins and spinulose teeth. Ethnobotany: Unknown Etymology: Baccharis is named for Bacchus, the god of wine, while bigelovii is named for Dr. John Milton Bigelow (1804-1878) a professor of botany who collected under the Whipple expedition. Synonyms: None Editor: SBuckley, 2010