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striped cottonthorn, striped horsebrush

Nuttall's horsebrush

Habit Shrubs, 50–200 cm. Shrubs, 10–120 cm.
Stems

1–5+, erect, spiny, unevenly pannose with glabrescent streaks.

1–5+, erect, spiny, pannose but for glabrescent streaks.

Leaves

primaries forming ascending spines, 10–30 mm;

secondaries filiform to clavate, 3–20 (× 1+) mm, glabrous or nearly so.

primaries forming straight or recurved spines, 5–25 mm;

secondaries spatulate, 10–20 mm, tomentose to nearly glabrous.

Peduncles

1–4 mm.

2–12 mm.

Involucres

turbinate, ca. 7 mm.

turbinate to cylindric, 6–9 mm.

Florets

5;

corollas pale yellow, ca. 9 mm.

4;

corollas bright yellow, 8–10 mm.

Phyllaries

5, oval-elliptic.

4, oblong.

Heads

2–5.

4–6.

Cypselae

2.5–3.5 mm, glabrous;

pappi of 75–100 bristles ca. 8 mm.

4–6 mm, densely hirsute;

pappi of 75–100 bristles 9–10 mm.

2n

= 60.

= 60.

Tetradymia argyraea

Tetradymia nuttallii

Phenology Flowering summer. Flowering spring–summer.
Habitat Rocky sites, pinyon-juniper woodlands Rocky or sandy places, sagebrush scrub or shadscale scrub
Elevation 1400–2100 m (4600–6900 ft) 1300–2100 m (4300–6900 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
NV; UT; WY
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 20, p. 631. FNA vol. 20, p. 631.
Parent taxa Asteraceae > tribe Senecioneae > Tetradymia Asteraceae > tribe Senecioneae > Tetradymia
Sibling taxa
T. axillaris, T. canescens, T. comosa, T. filifolia, T. glabrata, T. nuttallii, T. spinosa, T. stenolepis, T. tetrameres
T. argyraea, T. axillaris, T. canescens, T. comosa, T. filifolia, T. glabrata, T. spinosa, T. stenolepis, T. tetrameres
Name authority Munz & J. C. Roos: Aliso 2: 237. (1950) Torrey & A. Gray: Fl. N. Amer. 2: 447. (1843)
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