Participant Info

Species

Cirsium arvense [Breea arvense]

Family

Asteraceae

CommonName

creeping thistle, field thistle, Canadian thistle

Presence

YES

Status

exotic, noxious

EarliestDate

1938

LatestDate

2017

Ecosystem

basin, shrubland, foothill, montane

Geobotanical

Garitas, SSanjuans, Culebras, NCristos, UBasin, LBasin

Counties

Alamosa, Conejos, Costilla, Hinsdale, Mineral, Rio Grande, Saguache

Passes

WildlifePreserves

Baca, Big Meadows Reservoir, Blanca Wetlands, Home Lake

Other Localities

La Botica

PhotoRecords

YES Rich Haswell: Rio Grande Co, South Fork, vacant lot, 4 Sept 2013; 8 miles S of Del Norte by CR 13 23 Aug 2020

Comments

Creeping thistle, now exotic or adventive in every state of the USA, can also be found in nearly every county of the Watershed. The earliest date of 1938, from 1 mile N of Monte Vista, is inferred from specimens Francis Ramaley collected just before and after. Cirsium arvense is present in the Rio Grande drainage of New Mexico down to the border with Mexico, but it follows the drainage no farther. Note that the common name "Canadian thistle" promotes a bit of xenophobia, as Its origin is not Canada but Europe. It is on Colorado's B list of "noxious weeds."

Annotation