Cirsium rydbergii, the alcove thistle, or Rydberg's thistle, is North American species of perennial plants in the family Asteraceae, found in the Colorado Plateau and Canyonlands regions of the southwestern United States, in the States of Utah and Arizona.[3]: 111 

Cirsium rydbergii

Vulnerable  (NatureServe)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Genus: Cirsium
Species:
C. rydbergii
Binomial name
Cirsium rydbergii
Petr.
Synonyms[2]

Cirsium lactucinum Rydb.

Cirsium rydbergii is a large perennial herb sometimes reaching a height of 300 cm (10 feet). It has no or very few branches, and pinnately lobed leaves up to 90 cm (3 feet) long with many sharp spines but usually very few hairs. flower heads are spiny on the sides, containing white, pink, or purple disc florets but no ray florets.[4]

References

edit
  1. ^ "NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 18 April 2023.
  2. ^ The Plant List, Cirsium rydbergii Petr.
  3. ^ Canyon Country Wildflowers, Damian Fagan, 2nd ed., 2012, Morris Bush Publishing, LLC. in cooperation with Canyonlands Natural History Association, ISBN 978-0-7627-7013-7
  4. ^ Flora of North America, Rydberg’s or alcove thistle . Cirsium rydbergii Petrak