Prairie Buttercup - Ranunculus rhomboideus
State Rank Reason (see State Rank above)
Ranunculus rhomboideus is documented for Montana from a single collection made in 2020 and deposited at the University of Montana Herbarium (MONTU 167418). Since at least 1948 the western edge of Ranunculus rhomboideus' distribution has been mapped as extending into eastern Montana (Benson 1948; McGregor et al. [eds.] 1986; and Whittemore in Flora of North America 1997).
Stems erect, 5–33 cm with pilose foliage. Basal leaf blades 1–4 cm long, ovate, scalloped on the upper half. Flowers with petals 6–8 mm long, slightly longer than the pilose sepals. Achenes glabrous, ca. 2 mm long with curved beak <0.5 mm long; heads globose, 4–6 mm high (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX
AB to ON south to MT, NE, WI and IA (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus auricomus
, Bombus bifarius
, Bombus nevadensis
, and Bombus bimaculatus
(Macior 1968, Thorp et al. 1983).
- Literature Cited AboveLegend: View Online Publication
- Benson, L.D. 1948. A treatise on the North American Ranunculi. Amer. Midl. Naturalist 40:1-261.
- Flora of North America Editorial Committee. 1997. Flora of North America North of Mexico. Volume 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, Inc., New York, NY. xxiii + 590 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Macior, L.M. 1968. Bombus (Hymenoptera, Apidae) queen foraging in relation to vernal pollination in Wisconsin. Ecology 49:20-25.
- McGregor, R.L. (coordinator), T.M. Barkley, R.E. Brooks, and E.K. Schofield (eds). 1986. Flora of the Great Plains: Great Plains Flora Association. Lawrence, KS: Univ. Press Kansas. 1392 pp.
- Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.