Tetradymia argyraea |
Tetradymia spinosa |
|
---|---|---|
striped cottonthorn, striped horsebrush |
catclaw horsebrush, cotton-thorn horsebrush, shortspine horsebrush, spiny horsebrush |
|
Habit | Shrubs, 50–200 cm. | Shrubs, 10–100 cm. |
Stems | 1–5+, erect, spiny, unevenly pannose with glabrescent streaks. |
1–5+, erect or spreading, spiny, evenly pannose. |
Leaves | primaries forming ascending spines, 10–30 mm; secondaries filiform to clavate, 3–20 (× 1+) mm, glabrous or nearly so. |
primaries forming recurved spines, 5–25 mm; secondaries linear-filiform to spatulate, 3–25 (× 1–2) mm, glabrous or glabrescent. |
Peduncles | 1–4 mm. |
5–30 mm. |
Involucres | turbinate, ca. 7 mm. |
hemispheric, 8–12 mm. |
Florets | 5; corollas pale yellow, ca. 9 mm. |
5–8; corollas pale to bright yellow, 6–10 mm. |
Phyllaries | 5, oval-elliptic. |
4–6, oblong to ovate. |
Heads | 2–5. |
1–2 (in axils of spines). |
Cypselae | 2.5–3.5 mm, glabrous; pappi of 75–100 bristles ca. 8 mm. |
6–8 mm, copiously pilose (hairs 9–12 mm); pappi of ca. 25, subulate scales 6–9 mm. |
2n | = 60. |
= 60. |
Tetradymia argyraea |
Tetradymia spinosa |
|
Phenology | Flowering summer. | Flowering spring. |
Habitat | Rocky sites, pinyon-juniper woodlands | Usually sandy soils of alkali sinks, shadscale scrub, pinyon-juniper woodlands |
Elevation | 1400–2100 m (4600–6900 ft) | 800–2400 m (2600–7900 ft) |
Distribution |
CA
|
CA; CO; ID; MT; NM; NV; OR; UT; WY
|
Source | FNA vol. 20, p. 631. | FNA vol. 20, p. 632. |
Parent taxa | Asteraceae > tribe Senecioneae > Tetradymia | Asteraceae > tribe Senecioneae > Tetradymia |
Sibling taxa | ||
Name authority | Munz & J. C. Roos: Aliso 2: 237. (1950) | Hooker & Arnott: Bot. Beechey Voy., 360. (1839) |
Web links |