Chrysothamnus humilis |
Chrysothamnus molestus |
|
---|---|---|
Truckee green rabbitbrush, Truckee rabbitbrush |
Arizona rabbitbrush |
|
Habit | Shrubs, 10–30 cm; with woody, branched caudices, bark becoming dark gray, fibrous with age. | Shrubs, 8–20 cm; with woody, highly branched caudices, bark dark gray, highly fibrous with age. |
Stems | ascending, green, sparsely to densely puberulent, sparsely glandular. |
ascending, green, ± puberulent, stipitate-glandular. |
Leaves | ascending to spreading; sessile; blades with faint midnerves and pair of collaterals, narrowly elliptic to oblanceolate, 10–30 × 0.7–1.2 mm, flat to sulcate, apices acute (often apiculate), faces moderately puberulent, sparsely stipitate-glandular. |
erect to closely ascending; sessile; blades with ± evident midnerves, linear to narrowly elliptic, 7–20 × 0.7–1.5 mm, sulcate, sometimes apiculate, apices acute, faces moderately puberulent, uniformly stipitate-glandular. |
Involucres | turbinate, 6–10 × 3–4 mm. |
subcylindric, 9–11 × 2.5–3.5 mm. |
Disc florets | 2–3(–4); corollas 5.5–8 mm, lobes 1–1.7 mm; style branches 2–2.7(–3.4) mm (included in or barely surpassing spreading corolla lobes), appendages 0.8–1.4 mm (lengths about equaling stigmatic portion). |
5; corollas 5.5–7.5 mm, lobes 0.9–1.5 mm; style branches 2.7–3.2 mm, appendages 1–1.7 mm. |
Phyllaries | (12–)14–18 in 3–4 series, ± in vertical ranks, mostly tan, sometimes green-tipped, ovate or oblong to elliptic, unequal, 2.5–7.5 × 1–1.8 mm, chartaceous, outer ± herbaceous wholly or distally, weakly keeled, midveins faint, apices acute to obtuse, faces sparsely puberulent. |
± 20 in 4–5 series, in 4–5 strong vertical ranks, tan, often with green or dark subapical splotch, midnerves often obscure, linear or lanceolate to elliptic, 2–9 × 0.5–1.3 mm, unequal, outer ± herbaceous, inner chartaceous, strongly keeled, apices acute to rounded, tip cupped, faces of outer glabrous or puberulent. |
Heads | in densely cymiform arrays, often overtopped by distal leaves. |
in small cymiform to racemiform arrays. |
Cypselae | reddish brown, turbinate, 4–6 mm, densely hairy; pappi tan, 5–7 mm. |
tan, elliptic, 4.2–6 mm, mostly 5-ribbed, faces glabrous, sparsely glandular; pappi tan, 6–7.5 mm. |
2n | = 18. |
= 18. |
Chrysothamnus humilis |
Chrysothamnus molestus |
|
Phenology | Flowering summer–fall. | Flowering late summer–fall. |
Habitat | Sagebrush grasslands, open slopes in deserts, tolerant of alkali | Rocky soils, mostly on limestone pinyon-juniper woodland |
Elevation | 1400–3100 m (4600–10200 ft) | 1800–2400 m (5900–7900 ft) |
Distribution |
CA; ID; NV; OR; WA
|
AZ |
Discussion | Chrysothamnus molestus is known only from Coconino County. It is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 20, p. 189. | FNA vol. 20, p. 190. |
Parent taxa | Asteraceae > tribe Astereae > Chrysothamnus | Asteraceae > tribe Astereae > Chrysothamnus |
Sibling taxa | ||
Synonyms | C. viscidiflorus subsp. humilis | C. viscidiflorus var. molestus |
Name authority | Greene: Pittonia 3: 24. (1896) | (S. F. Blake) L. C. Anderson: Madroño 17: 222. (1964) |
Web links |