Burke: Cirsium altissimum vs. Cirsium undulatum

	Cirsium altissimum	Cirsium undulatum
		wavy leaf thistle
Habit		Stout, short-lived perennial from a tap-root, branched above and sometimes below the surface, 3-12 dm. tall, densely, closely, and persistently white-woolly throughout.
Leaves		Leaves up to 3 dm. long, coarsely toothed to pinnatifid, the lobes ovate or deltoid, usually over 7mm. wide, the margins spiny.
Flowers		Heads several to numerous at the ends of the branches; involucre 2.5-4 cm. high, its bracts with a glandular-glutinous dorsal ridge, the inner with pointed tips, the others with spine tips 3-5 mm. long; flowers all ligulate, pink-purple, but often so pale as to appear dirty-white.
Fruits		Achenes 4-7 mm. long, light brown.

	Cirsium altissimum	Cirsium undulatum
Flowering time		May-September
Habitat		Dry hillsides and plains at low elevations.
Distribution	[WildflowerSearch map] [BONAP county map]	Occurring east of the Cascades crest in Washington; British Columbia to California, east to Michigan and Texas. [WildflowerSearch map] [BONAP county map]
Origin		Native
Conservation status		Not of concern
Sibling taxa	C. arvense, C. brevifolium, C. brevistylum, C. edule, C. flodmanii, C. hookerianum, C. inamoenum, C. remotifolium, C. scariosum, C. undulatum, C. vulgare	C. arvense, C. brevifolium, C. brevistylum, C. edule, C. flodmanii, C. hookerianum, C. inamoenum, C. remotifolium, C. scariosum, C. vulgare
Web links	Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Cirsium altissimum

Cirsium undulatum

wavy leaf thistle

Habit

Stout, short-lived perennial from a tap-root, branched above and sometimes below the surface, 3-12 dm. tall, densely, closely, and persistently white-woolly throughout.

Leaves

Leaves up to 3 dm. long, coarsely toothed to pinnatifid, the lobes ovate or deltoid, usually over 7mm. wide, the margins spiny.

Flowers

Heads several to numerous at the ends of the branches;

involucre 2.5-4 cm. high, its bracts with a glandular-glutinous dorsal ridge, the inner with pointed tips, the others with spine tips 3-5 mm. long;

flowers all ligulate, pink-purple, but often so pale as to appear dirty-white.

Fruits

Achenes 4-7 mm. long, light brown.