CPC Plant Profile: Royal Gorge Stickleaf
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Plant Profile

Royal Gorge Stickleaf (Mentzelia densa)

Closeup of a bright yellow flower and buds. Photo Credit: Susan Spackman
  • Global Rank: G2 - Imperiled
  • Legal Status: N/A
  • Family: Loasaceae
  • State: CO
  • Nature Serve ID: 151385
  • Date Inducted in National Collection: 02/10/1987

Mentzelia densa forms a dense ball up to a meter tall of prickly leaves. These prickly leaves look like miniature Chinese pagodas and easily catch onto clothing and fur. Flowers appear mid-summer and are sunburst-like. The fruit is an oblong dry capsule which is believed to be dispersed by animals, via fur attachment (CNSP 1997). This species is found from only one location in central Colorado, on granite (Coles 1990).

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Nature Serve Biotics
  • 05/02/2017

There are 16 occurrences known, and about 6 are of good viability. This is a locally common, narrow endemic of the drainages and main canyon of the Arkansas River in central Colorado (a range only about 40 km long). Threats to the species include recreational use of habitat, highway construction and maintenance and, residential/vacation home development.

Thomas Grant
  • 01/01/2010

Possible rerouting of US Highway 50 might affect known populations (Von Bargen 1997).

Thomas Grant
  • 01/01/2010

Only one known population (Von Bargen 1997).

Thomas Grant
  • 01/01/2010

None known.

Thomas Grant
  • 01/01/2010

There is no formal management plan.

Thomas Grant
  • 01/01/2010

Research needs include understanding this species reproductive biology and ecology, habitat requirements and population dynamics.


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Taxon Mentzelia densa
Authority Greene
Family Loasaceae
CPC Number 2822
ITIS 503767
Common Names Royal Gorge blazingstar | Royal Gorge stickleaf
Associated Scientific Names Mentzelia densa | Nuttallia densa
Distribution M. densa is known from one location in Colorado (Coles 1990).
State Rank
State State Rank
Colorado S2

M. densa can be found growing in washes and naturally disturbed sites, and steep rocky slopes. Underlying bedrock includes granite, gneiss, gravel, and scree. It can also be found on dry open sites, often with pinyon-juniper, sagebrush, or mountain mahogany at elevations of 5800-7200 ft. (Coles 1990).

Ecological Relationships

Often found with pinyon-juniper, sagebrush, or mountain mahogany. (Von Bargen 1997).

Common Name Name in Text Association Type Source InteractionID
Bees Confirmed Pollinator Link
Flies Confirmed Pollinator Link
Lead Institution State Reintroduction Type Year of First Outplanting

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