Cirsium Geneus
Cynareae Tribe-Asteraceae
| Cirsium | arizonicum Arizona Thistle |
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| Arizona thistle is found in Arizona and adjacent states. The specimens here were observed at about 6,700 feet on the Bright Angel Trail in the Grand Canyon and in Bryce Canyon at 7,600 feet. Both specimens were growing on sandy soil. | |||||
Cirsium |
arvense
Canada Thistle |
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| Arvense means "of cultivated lands". Canada thistle is considered an invasive species in all western states. This specimen was growing on the western shore of Grand Lake, Colorado between the high and low water marks. It was part of a natural flower garden composed of Carduus nutans (Musk Thistle), CallCirsium vulgare (Bull Thistle), Calylopus serrulatus (Yellow Sundrops), Penstemon glaber, and Verbascum thapsis (Mullein). All of these species thrive on the shallow, sunny gravel slopes between the low and high water lines. A different community, composed mostly of Matricaria maritima flourishes on the muddy flats. | |||||
Cirsium |
canescens Prairie Thistle |
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Canescens means greyish (L.). The prairie thistle grows on open grasslands and plains. The species here prefer sandy plains at the edge of the Great Sand Dunes in Great Sand Dunes National Park in Colorado at 8,100 feet on a blustery day in early June. The thistle was growing in a grassland community on very sandy soil on the "sand sheet" adjacent to the dunes. Nearby species include Thelesperma subnudatum (Sand Fringepod), Cryptantha fendleri (Sand Dunes Cat Eve), Lappula Occidentalis (Wesern Stickseed), Euphorbia robusta, andPenstemon angustifolius (Taperleaf penstemon). These are generally typical sand sheet species. Nearby shrubs include Rosa woodsi. Cottonwoods are common along Medano Creek which is often flowing at this elevation in June. As the soil grows more sandy approaching the dunes nearly all plants are absent in the shifting sands. Near Wray, Colorado Cirisium canescens is also found in sandy soil but in a different plant community. The community in Wray is a sandy grassland community not a sand sheet. Canescens grows in roadside ditches at 3,500 foot elevation. Nearby herbs include Hymenopappus flavescens (Collegeflower), Helianthus petiolaris (Prairie Sunflower), and Apocynum cannibum (Indian hemp). Cirsium cansecens is found in Rocky Mountain and plains states in a broad region centered on Wyoming. |
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| Cirsium | neomexicanum New Mexico Thistle |
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| Cirsium neomexicanum is widespread in the southwest. The specimen here was growing in Embudo Canyon in the Sandia Mountains at 6,600 foot elevation. This is a desert environment and the soil is a gravel outwash from the decay of precambrian Sandia Granite. Associated species include yucca glauca (Narrow Leaf Yucca), Heterotheca villosa (Hairy Golden Aster), Machaeranthera pinnatifida (Spiny Golden Aster), Stephanomeria pauciflora (Skeletonweed), and Tetraneuris ivensia (Ives Bitterweed). A similiar specimen was observed near Sheep Bridge, Arizona at 3,000 foot elevation in association with Sonoran Desert Flora (upland division). | |||||
| Cirsium | pallidum |
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| Cirsium pallidum, Yellow Thistle growing in a grassy meadow on Capitan Mountain, New Mexico, at 9,500 foot elevation. Growing in association with Pseudotsuga mentzeii (Douglas Fir), Chenopodium gravelons, and (Verbena macdougalii). | |||||
| Cirsium | scariosum Elk Thistle |
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| Scariosum means dry or shriveled. The above specimen of Cirsium scariosum was growing in open meadows at the Rocky Mountain Biological Laboratory in Gothic, Colorado. Elevation was 9,500 feet. .Flowers whitish with pink center.Plant height 1.1 meters. Leaves basal and stem, stem alternate, basal length 31cm., width 9 cm. no petiole. Stem leaves are 130 mm long, 50 mm wide,no petiole. Flower heads are 30 mm wide and long.This is a sunny, open, West Facing meadow that gets good sun and lots of winter snow. The plant associations in Pyrrocoma corcea ( Curly Goldenweed), Helienthella quinquinervis (Aspen Sunflower), and Helinathum hoopsei (OrangeSneezeweed). | |||||
| Cirsium | scopulorum Subalpine Thistle |
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| Scopulorum means "grows on cliffs". Subalpine thistle grows in alpine meadows, generally at or above timberline. This specimen was growing near the gravel pit at Glen Cove in subalpine meadows on Pikes Peak , Colorado. Elevaton was 11,500 Feet,date July 30, 2007. Plant height is 43 cm. plant width about 33 cm. Leaves basal and stem. Basal leaf lenght is 19 cm , width 40 mm. Stem leaf lenght is 19 cm, width 45 mm. Flower width is 45 mm, width 33 mm, length 30 mm. These meadows are open, slightly rolling, below north facing cliffs with good sun. Associated flora include Antennaria rosea (Rosy pussytoes, Erigeron pinnatisectus, and Erigeron perigrinus. The latter two species are close to the edge of the meadow, almost in the shade of near timberline Picea engelmanii, (Engelmann Spruce). |
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| Cirsium | undulatum Wavy leaf Thistle |
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| Wavy leafed Thistle, Cirsium undulatum, was growing on the Barr Trail above colorado springs at an elevation of 6,800 feet. This thistle is often observed in the plains but this Barr Trail habitat is an east facing gravel outwash from the Pikes Peak granite and is fairy dry. Associated flora include | |||||
