Thelypodium paniculatum
Author: A. Nels.

northwestern thelypody

Brassicaceae (Mustard Family)

Taxonomic Comments

=Thelypodium sagittatum var. crassicarpum.

Ranks and Status

Global rank: G2
State rank: SH
Federal protection status: None
State protection status: None

[+] Description and Phenology

General description: Northwestern thelypody is an herbaceous biennial or short-lived perennial with solitary, simple or branched stems that are 3-7 dm high and arising from a taproot. Its lower leaves are 4-10 cm long and have petioles and narrowly lance-shaped, entire-margined blades. The upper stem leaves are 2-6 cm long and lance-shaped with basal wings that clasp the stem. Foliage is glabrous and has a thin, waxy coating. Flowers are borne on ascending stalks in cylindric inflorescences that are up to 35 cm long when mature. Each flower has 4 separate sepals that are 5-8 mm long, 4 separate, lavendar petals that are 10-16 mm long and 2-6 mm wide, and 4 long and 2 short stamens. The ascending, straight, cylindrical capsules, or siliques, are not flattened, and are 25-40 mm long and 1.3-2.3 mm wide.

Look Alikes: This species is similar to T. sagitatum, but the latter has fruits less than 1.2 mm wide and petals less than 3 mm wide. Thelypodium paniculatum might also be confused with species of Arabis, but those plants have flattened rather than cylindrical siliques.

Phenology: Flowering and fruiting in June-July (Ackerfield 2012).

[+] Habitat

In Colorado this species is found in meadows and stream bottoms.

Elevation Range: 7,000 - 8,000 feet (2,134 - 2,438 meters)

[+] Distribution

Colorado endemic: No
Global range: Documented range includes southwestern Montana (historical in Beaverhead Co. and reported from Madison Co. [Dorn 1984]), western Wyoming (Park, Teton, Sublette, Lincoln, Uinta, and Fremont cos. [Rocky Mountain Herbarium 1998]), and adjacent southeastern Idaho (Bonneville Co. [Holmgren et al. 2005]); the species recurs in southeastern Wyoming (Carbon and Platte cos. [Rocky Mountain Herbarium 1998]) and north-central Colorado (Jackson and Moffat Cos. [Ackerfield 2012]). Range size is on the order of 100,000 square km.
State range: Known from Moffat and Jackson counties in Colorado (Ackerfield 2012).

[+] Threats and Management Issues

In Colorado, this species is known from one historical general record (1903) on private land in Jackson County, and one historical record in Moffat County. This species is ranked S2 in Wyoming, S1 in Idaho, and SH (extirpated) in Montana (NatureServe 2013).

[+] References

    • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.
    • Al-Shehbaz, I.A. 1973. Biosystematics of Thelypodium. Contributions from the Gray Herbarium of Harvard University 204:3-148.
    • Colorado State University Herbarium. 1999. "Colorado State University Herbarium Database". database.html. (May 15 1999).
    • Flora of North America Editorial Committee, ed. (FNA). 1993+. Flora of North America North of Mexico. Oxford Univ. Press, New York, Oxford.
    • Flora of North America Editorial Committee. 2010. Flora of North America North of Mexico. Vol. 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, New York. xxii + 797 pp.
    • Harrington, H.D. 1954. Manual of the plants of Colorado. Sage Press, Chicago. 666 pp.
    • Holmgren, N.H., P.K. Holmgren, and A. Cronquist. 2005. Intermountain flora. Volume 2, part B. Subclass Dilleniidae. The New York Botanical Garden Press. 488 pages.
    • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
    • Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
    • Lesica, P. 2003. Conserving globally rare plants on lands administered by the Dillon Office of the Bureau of Land Management. Report to the USDI Bureau of Land Management, Dillon Office. Montana Natural Heritage Program, Helena, MT. 22 pp. plus appendices.
    • Montana Field Guide. 2008. Accessed online at: (August 2008)
    • Montana Natural Heritage Program. 1999. Biological Conservation Database. (May 15 1999).
    • NatureServe. 2015. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available (Accessed: 2015).
    • Neely, B., S. Panjabi, E. Lane, P. Lewis, C. Dawson, A. Kratz, B. Kurzel, T. Hogan, J. Handwerk, S. Krishnan, J. Neale, and N. Ripley. 2009. Colorado Rare Plant Conservation Strategy, Developed by the Colorado Rare Plant conservation Initiative. The Nature Conservancy, Boulder, Colorado, 117 pp.
    • Rocky Mountain Herbarium. 1998. Atlas of the Vascular Flora of Wyoming. University of Wyoming. Online. Available: (accessed 2009).
    • Rollins, R.C. 1993. The Cruciferae of continental North America: Systematics of the mustard family from the Arctic to Panama. Stanford Univ. Press, Stanford, California. 976 pp.
    • USDA, NRCS. 2013. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.
    • 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.
    • Weber, W.A., and R.C. Wittmann. 1996a. Colorado flora: Eastern slope. Revised edition. Univ. Press of Colorado, Niwot, Colorado. 524 pp.

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