Mimulus gemmiparus
Author: W.A. Weber

Rocky Mountain monkeyflower

Scrophulariaceae (figwort family)

Close up of Mimulus gemmiparus by Susan Spackman Panjabi.

Close up of Mimulus gemmiparus by Jill Handwerk.
Close up of Mimulus gemmiparus by Jill Handwerk, under greenhouse conditions.
Close up of Mimulus gemmiparus by Jill Handwerk, under greenhouse conditions.

Taxonomic Comments

Ackerfield (2015) and others place this species in the Phrymaceae, or Lopseed Family.

Ranks and Status

Global rank: G1
State rank: S1
Federal protection status: USFS Sensitive
State protection status: None

Description and Phenology

Illustration of Mimulus gemmiparus by Janet Wingate.

General description: A small, inconspicuous, annual herb, 1-10 cm tall, only infrequently producing sterile flowers and only above ground between 1 and 2 months a year (Beardsley and Steingraeber 2013). Reproduction is by propagule, or bulbil, a dormant embryonic shoot forms inside a modified leaf stem or petiole, which are swollen, and sac-like. These fall off the mother plant as it matures. Flowers yellow when present; 4-5 mm long, solitary, either terminal or from leaf axil (Spackman et al. 1997). Plants are completely glabrous, unbranched, with opposite, ovate leaves up to 10 mm long and 7 mm wide (Peterson 1983).

Look Alikes: Mimulus gemmiparus is the only Mimulus species with this specific reproductive mechanism. Its leaf petiole bases are modified to form pockets containing dormant embryonic shoots; flowers are usually absent (Spackman et al. 1997).

Phenology: Flowers are rarely produced in this annual species. When they are produced, they have been observed in mid-July (Spackman et al. 1997).


Habitat of Mimulus gemmiparus by Jill Handwerk.

Habitat of Mimulus gemmiparus by Susan Spackman Panjabi.

Habitat of Mimulus gemmiparus by Jill Handwerk.

Habitat of Mimulus gemmiparus by Jill Handwerk.

A subalpine species found on granite outcrops with surface seepage water and on moist forest soils near seeps and springs. Usually found in areas protected by granite overhangs and usually associated with other Mimulus species. Also found on an alluvial fan deposited by the Lawn Lake flood. The species' propagules are thought to be water-dispersed. Granitic seeps, slopes and alluvium in open sites within spruce-fir and aspen forests (Spackman et al. 1997, Steingraeber and Beardsley 2005).

Elevation Range: 8,359 - 11,201 feet (2,548 - 3,414 meters)


Colorado endemic: Yes
Global range: Endemic to Colorado. Known from Boulder, Clear Creek, Grand, Jefferson, and Larimer counties. Estimated range is 2,519 square kilometers (972 square miles), calculated in GIS by the Colorado Natural Heritage Program in 2008 by drawing a minimum convex polygon around the known occurrences.
Distribution of Mimulus gemmiparus in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).

Distribution of Mimulus gemmiparusin Colorado.

Threats and Management Issues

Summary results of an analysis of the status of Mimulus gemmiparus based on several ranking factors. This species was concluded to be "Effectively Conserved”. From Rondeau et al. 2011.

Recreational activities are considered to be the primary threats to the species at this time (Rondeau et al. 2011) combined with the fact that the total population of this species is small, known from a very small area, and is highly vulnerable to stochastic events by one of the threats mentioned below. Most of the M. gemmiparus locations occur in close proximity to trails or roads. Because M. gemmiparus tends to grow in dense colonies within small areas, one minor disturbance could extirpate an entire population. Beardsley and Steingraeber (2013) provide evidence that these sorts of events are common and unpredictable. For example, a group of hikers sought refuge from a storm in 2010 under the rock ledge that overhangs a population of M. gemmiparus and could have easily trampled the small plants (Beardsley and Steingraeber 2013). Therefore, M. gemmiparus could be easily impacted or trampled by off-trail activity by tourists, hikers, and horses or trail maintenance activities. Existing M. gemmiparus populations are also susceptible to ecological or human-related disturbances that could alter soil conditions, affect hydrology, or increase competition with other species. Ecological disturbances could include succession, wildfire, drought, rock fall, flash flood, erosion, climate change, tree blowdown, and invasion of exotic plants (Beatty et al. 2003). Further, Colorado climate scenarios for 2050 suggest temperature will increase by 3-7 F and precipitation may decrease or increase. The impact to any given rare plant habitat is likely to vary. Long-term monitoring that includes weather and soil moisture data is critical to understanding climate impacts.


    • Beardsley, M. and D. A. Steingraeber. 2013. Population dynamics, rarity and risk of extirpation for populations of Mimulus gemmiparus (budding monkeyflower) on National Forests of Colorado. A research report submitted to the USFS Forest Service. Arapaho and Roosevelt National Forets and Pawnee National Grassland. pp 17. Accessed online on May 11 at: http://www.r5.fs.fed.us/wildflowers/Rare_Plants/profiles/Critically_Imperiled/mimulus_gemmiparus/ documents/USFS_MimulusStatusReport2013.pdf
    • Beatty, B.L., W.F. Jennings, and R.C. Rawlinson. 2003. (November 21). Mimulus gemmiparus W.A. Weber (Rocky Mountain monkeyflower): a technical conservation assessment. [Online]. USDA Forest Service, Rocky Mountain Region. Available: http://www.fs.fed.us/r2/projects/scp/assessments/mimulusgemmiparus.pdf [March 2006].
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    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
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    • O'Kane, S. L. 1988. Colorado's Rare Flora. Great Basin Naturalist. 48(4):434-484.
    • Peterson, J.S. 1983. Status report for Lupinus crassus. Unpublished report prepared for the Colorado Natural Heritage, Ft. Collins, CO.
    • Peterson, J.S. 1983. Status report of Mimulus gemmiparus. Unpublished report prepared for the Colorado Natural Areas Program Denver, CO by the Colorado Natural Heritage Program, Ft. Collins, CO.
    • Rondeau, R., K. Decker, J. Handwerk, J. Siemers, L. Grunau, and C. Pague. 2011. The state of Colorado's biodiversity 2011. Prepared for The Nature Conservancy. Colorado Natural Heritage Program, Colorado State University, Fort Collins, Colorado.
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    • Steingraeber, D.A. and M. Beardsley. 2005. Mimulus gemmiparus Populations: Current Status and Extended Search.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Eastern Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 555 pp.
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