Tetradymia spinosa |
Tetradymia filifolia |
|
---|---|---|
catclaw horsebrush, cotton-thorn horsebrush, shortspine horsebrush, spiny horsebrush |
threadleaf horsebrush |
|
Habit | Shrubs, 10–100 cm. | Shrubs, 1–5+ dm. |
Stems | 1–5+, erect or spreading, spiny, evenly pannose. |
1–5+, erect, unarmed, tomentose to glabrescent. |
Leaves | primaries forming recurved spines, 5–25 mm; secondaries linear-filiform to spatulate, 3–25 (× 1–2) mm, glabrous or glabrescent. |
primaries linear-subulate, 5–20+ mm, floccose, sometimes glabrate; secondaries linear-filiform, 3–15 mm. |
Peduncles | 5–30 mm. |
3–15 mm. |
Involucres | hemispheric, 8–12 mm. |
turbinate, 7–10 mm. |
Florets | 5–8; corollas pale to bright yellow, 6–10 mm. |
4; corollas cream to bright yellow, 9–10 mm. |
Phyllaries | 4–6, oblong to ovate. |
4, lanceolate to obovate. |
Heads | 1–2 (in axils of spines). |
3–7. |
Cypselae | 6–8 mm, copiously pilose (hairs 9–12 mm); pappi of ca. 25, subulate scales 6–9 mm. |
3–5 mm, hirsute; pappi of 100–130 (distally dilated) bristles 6–8 mm. |
2n | = 60. |
= 120. |
Tetradymia spinosa |
Tetradymia filifolia |
|
Phenology | Flowering spring. | Flowering summer. |
Habitat | Usually sandy soils of alkali sinks, shadscale scrub, pinyon-juniper woodlands | Pinyon-juniper woodlands, sometimes gypseous soils |
Elevation | 800–2400 m (2600–7900 ft) | 1500–1800 m (4900–5900 ft) |
Distribution |
CA; CO; ID; MT; NM; NV; OR; UT; WY
|
NM |
Source | FNA vol. 20, p. 632. | FNA vol. 20, p. 630. |
Parent taxa | Asteraceae > tribe Senecioneae > Tetradymia | Asteraceae > tribe Senecioneae > Tetradymia |
Sibling taxa | ||
Name authority | Hooker & Arnott: Bot. Beechey Voy., 360. (1839) | Greene: Bull. Torrey Bot. Club 25: 123, plate 334, figs. 3, 4. (1898) |
Web links |