Trisetum × orthochaetum Hitchc. (1934:134)
Missoula County oats, Bitterroot trisetum
Taxonomy & Nomenclature
An unplaced name according to POWO (2024).
Conservation Status
Invalid [hybrid] (Montana State Library, 2026)
Last record: 23 July 1908 (Ripley, 1975:45 [as 1908]); 9 July 1951 (Shelly, 1986:1)
Rediscovered in: July 1986 (Shelly, 1986:2-3, 1987)
This taxon was considered probably Extinct (i.e. "prEX") with a last record of 1908 by (Ripley, 1975:45). This 1908 record is presumably that collected on 23 July 1908 as recorded by (Shelly, 1986:1). And it was listed as Extinct by the Montana Rare Plant Project (Lesica et al., 1984). The taxon was rediscovered in July 1986 by J. Stephen Shelly and Ginger V. King (Shelly, 1986:2-3, 1987), and it has since been recorded at multiple other sites within the county (Montana State Library, 2026).
Distribution & Habitat
Glacier County and the Granite Creek Drainage, Missoula County, Montana, USA
Type locality: "Boggy meadow, Bitterroot Mountains, alt. 1200 meters, near Lolo Hot Springs, Missoula County, Montana" (Shelly, 1986:1)
Anatomy & Morphology
Biology & Ecology
It is very likely of hybrid origin and ephemeral as germination rates are practically null (Shelly, 1986:40-41; Montana State Library, 2026). The type specimen has abortive anthers (Shelly, 1986:40).
Hypodigm
Media
References
Original scientific description:
Hitchcock, A. S. (1934). New species, and changes in nomenclature of grasses of the United States. Amer. J. Bot. 21: 127-139.
Other references:
Clayton, W. D., Harman, K. T. and Williamson, H. (2006). World Grass Species - Synonymy database The Board of Trustees of the Royal Botanic Gardens, Kew.
Flora of North America Editorial Committee (FNA). (2007). Flora of North America north of Mexico. Vol. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford Univ. Press, New York. xxviii + 911 pp.
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.
Lesica, P., Husby, P. and Cooper, S. V. (1998). Noteworthy collections: Montana. Madroño 45:328-330.
Lesica, P., Lavin, M. T. and Stickney, P. F. (2012). Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
Lesica, P., Moore, G., Peterson, K. M. and Rumely, J. H. (1984). Vascular plants of limited distribution in Montana. Monograph No. 2, Montana Academy of Sciences, Supplement to the Proceedings, Vol. 43. 61 pp.
Montana State Library. (2026). Missoula County Oats — Trisetum orthochaetum. Montana Field Guide. Montana Natural Heritage Program. Retrieved on August 17, 2026, from https://FieldGuide.mt.gov/speciesDetail.aspx?elcode=PMPOA690M0
POWO. (2024). Plants of the World Online (online resource). Facilitated by the Royal Botanic Gardens, Kew, United Kingdom. Available at: https://powo.science.kew.org/ [Accessed 7 December 2024]
Ripley, S. Dillon. (1975). Report on endangered and threatened species of the United States. House Document 94-51: 1-200 [45].
Shelly, J. Stephen. (1986). Report on the conservation status of Trisetum orthochaetum, a candidate endangered species. Unpublished report. Montana Natural Heritage Program, Helena, MT 41 pp.
Shelly, J. Stephen. (1987). Rediscovery and preliminary studies of Trisetum orthochaetum, Missoula County, Montana. Proceedings Montana Academy of Science 47: 3-4 (Abstr.).
Watson, T. J., Jr. (1976). An evaluation of putatively threatened or endangered species from the Montana flora. Prepared for USDA Forest Service, Missoula, MT. 31 pp.
https://fieldguide.mt.gov/speciesDetail.aspx?elcode=PMPOA690M0