Cirsium altissimum |
Cirsium undulatum |
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wavyleaf thistle |
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Habit | Plants perennial, 2–23 dm; taprooted, often with well-developed lateral roots. | |
Stems | 1–several, white-tomentose. |
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Leaves | elliptic to ovate, 10–40 × 1–10(14) cm; margins shallowly dentate to deeply pinnate, undulate; spines 2–12 mm; surfaces abaxially densely white-tomentose, adaxially glabrate to sparsely tomentose; basal occasionally present at flowering, sessile, clasping, or petiolate. |
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Involucres | ovoid to campanulate, 2.5–4.5 × 1.5–4.5 cm, glabrate to thinly tomentose. |
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Florets | corollas 24–50 mm, white to pale lavender or pink; tubes 12–28 mm; throats 6–14 mm; lobes 7–13 mm; style tips 5–7.5 mm. |
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Phyllaries | imbricate, with prominent glutinous ridges; spines spreading to reflexed, 1.5–5 mm. |
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Fruits | 6–7 mm; light to dark brown; pappi 20–40 mm. |
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Heads | 1–10. |
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Cirsium altissimum |
Cirsium undulatum |
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Distribution | ||
Discussion | Sagebrush areas, dry hillsides, prairies, disturbed areas, roadsides. Flowering May–Aug. 50–1400 m. Col, ECas, Lava, WV. CA, ID, NV, WA; north to British Columbia, northeast to Manitoba, east to MI, southeast to TX, south to Mexico, GA, PA. Native. |
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Source | Flora of Oregon, volume 2, page 230 Bridget Chipman |
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Sibling taxa | ||
Web links |
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