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Family: Asteraceae
yellow rabbitbrush
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Shrubs, 10-120 cm; with woody, branched caudices, bark whitish tan, becoming gray, flaky and fibrous with age. Stems ascending, green, soon becoming tan, glabrous or puberulent, sometimes resin-dotted, often resinous. Leaves ascending, spreading, or deflexed; sessile; blades with evident midnerves plus sometimes 1-2 pairs of smaller, collateral nerves, linear to lanceolate, 10-75 × 0.5-10 mm, flat or sulcate, often twisted, margins often undulate, sometimes ciliate, apices acute to apiculate, faces glabrous or puberulent. Heads in dense, rounded cymiform arrays (to 7 cm wide), not overtopped by distal leaves. Involucres cylindric to obconic or campanulate, 4-7 × 1.5-2.5 mm. Phyllaries 12-24 in 3-5 series, in spirals or weak vertical ranks, mostly tan, green to brown subapical patch often present, midnerves usually evident (at least distally), linear-oblong, lanceolate to elliptic or obovate to spatulate, 1-5 × 0.5-1.2 mm, unequal, chartaceous, margins scarious, eciliate or ciliolate to erose-ciliolate, flat or convex, sometimes weakly keeled, apices acute to obtuse or rounded, sometimes apiculate, flat, faces glabrous or puberulent. Disc florets (3-)4-5(-14); corollas 3.5-6.5 mm, lobes 0.7-1.7 mm; style branches 2.2-3.2 mm (exserted beyond spreading corolla lobes), appendages 0.8-1.5 mm (length shorter than stigmatic portion). Cypselae tan to reddish brown, turbinate, 2.5-4.2 mm, ± 5-angled, moderately to densely hairy; pappi tan, 3.5-6 mm. FNA 2006, Heil et al 2013, McDougall 1973, Kearny and Peebles 1979 Common Name: yellow rabbitbrush Duration: Perennial Nativity: Native Lifeform: Shrub General: Shrubs, 10-120 cm tall, from woody, branched caudices; bark whitish tan, becoming gray, flaky and fibrous with age; stems ascending, green, soon becoming tan, often resinous. Leaves: Opposite and sessile; blades linear to lanceolate, 1-8 cm long by 0.5 cm wide, flat and often twisted, with evident midnerves plus sometimes 1-2 pairs of smaller, collateral nerves; margins often undulate, sometimes ciliate; apices acute to apiculate; faces glabrous or puberulent, sometimes with punctate glands. Flowers: Flower heads discoid, arranged in dense, rounded panicles, elevated above the leaves; involucre (ring of bracts wrapped around the flower head) cylindric to campanulate, 4-7 mm high by 2 mm wide, the bracts (phyllaries) in 3-5 series, in spirals or weak vertical ranks, mostly tan, often with a green to brown subapical patch, margins scarious and often ciliate, faces glabrous or puberulent; florets 4-5 per head, all discs, the corollas yellow, 4-6 mm long, style branches exserted beyond spreading corolla lobes. Fruits: Achenes tan to reddish brown, turbinate, 2-4 mm long, moderately to densely hairy, topped with a pappus of tan bristles, 3-6 mm long. Ecology: Found in dry, often sandy soils in high deserts and juniper woodlands, or on alpine/subalpine slopes (vars viscidiflorus and puberulus), above 4,000 ft (1219 m); flowers late summer-fall. Distribution: w N. Amer. from British Columbia, MT, and SD south to CA, AZ and NM. Notes: This widespread rabbitbrush is distinguished by its bunches of straight, ascending to erect stems, usually less than 0.5 m tall (var. viscidiflorus up to 1.2 m tall); sticky yellow flowers arranged in flat-topped or gently rounded clusters at the top of the plant; and flat, upward-pointing leaves which are often twisted into a gentle spiral. There are 5 currently accepted subspecies (according to FNA), all of which are found in the Southwest. Ethnobotany: Applied topically to treat boils, toothaches, and rheumatism; infusions taken for colds, coughs, flu, and as an emetic; plant used as a culinary herb; roots used as a chewing gum; flowers used to make a yellow-orange dye for wool, leather, cotton, and baskets; used as a sand break to protect young corn and melons, and used as thatch to prevent the sand on top of the sweathouse from sifting through; stems used to brush spines off prickly pear fruits. Etymology: Chrysothamnus from the Greek chryseos, golden, and thamnos, bush; viscidiflorus translates to sticky-flowered Synonyms: Crinitaria viscidiflora Editor: AHazelton 2015 |
