Caltha chionophila Greene ?
Annotated by Keir M. Wefferling, May 2017. Remarks: University of Wisconsin- Milwaukee

Montana: Ravalli County: Bitterroot National Forest, Lost Trail Pass, subalpine sphagnum meadow next to ski area just off Hwy 93, on MT/ID border. Elev. 2350 m.
Meadow ca 1 h in size with scattered shallow pools surrounded by saturated muck flats dominated with Eleocharis pauciflora, Carex limosa, C. aquatilis and Menyanthes trifoliata. Sphagnum hummocks between open water with very low growing Kalmia microphylla, C. praeceptorum, Drosera anglica and Pedicularis groenlandica. Occasional raised areas formed by trees of Pinus contorta and P. albicaulis with understory of Ledum glandulosum and vaccinum occidentale. The rest of the meadow charecterized by mixed stand of C. rostrata, C. aquatilis, C. prionophylla on moist to wet peat, mostly without sphagnum cover. Prominent on N end of meadow w C. rostrata, C. aquatilis, Dodecatheon jeffreyi on wet substrate with and without moss cover. Phenology: Flowers.

Robert Bursik 1472, Aug 4, 1988
With C. Clemens and F. Rabe
ID, Accession: 101580, Barcode: ID039963