Sheathed Wildparsley

Musineon vaginatum Rydb. Mem. N. Y. Bot Gard. 1: 288. 1900.
Plants caulescent, 4-30 cm. high, the stems purplish-tinged, scaberulous at the base of the umbel, otherwise glabrous; leaves broadly ovate to oblong-ovate in general outline, excluding the petioles 1-10.5 cm. long, 1.5-4 cm. broad, ternate, then 1-2-pinnate, the leaflets ovate, pinnately lobed, 5-11 mm. long, 2-5 mm. broad, rarely scaberulous above; petioles 1-4 cm. long, inflated at the base into a conspicuous, purplish, scarious-margined sheath; peduncle usually exceeding the leaves; involucre wanting, or rarely present as a low sheath;
* As "Musenium." invokicel of linear-lanceolate bractlets, 2-5 mm. long, shorter than the white or yellowish flowers; rays several, 4-17 mm. long; pedicels 2-4 mm. long; fruit ovoid-oblong, 3-4 mm. long, 1-2 mm. broad, glabrous to densely scaberulous, the oil-tubes usually 3 in the intervals, 4—5 on the commissure, the seed-face plane.
Type locality: Bridger Mountains, Montana, Rydberg & Bessey 4626.
Distribution: Bridger Mountains, Montana; Big Horn Mountains, Wyoming; northern Utah