This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Perennial, nearly or quite acaulescent herbs, with 1-3-pinnate leaves, their segments small, short and broad, the flowers white or purple. Calyx-teeth distinct. Fruit glabrous, ovate to orbicular, each carpel with 3-5 broad thin wings. Stylopodium none. Oil-tubes 2 or 3 in each interval, 4-8 on the commissural side. [Greek, referring to the broad wings of the fruit.]
About 5 species, natives of the central and western United States, the following typical.
Cymopterus montanus T. & G. Fl. N. A. 1: 624. 1840.
Somewhat glaucous, or very slightly pubescent. Leaves 1'-6' high, stout-petioled, pinnate, or bipinnate, the segments oblong, obtuse, entire, toothed, or lobed; peduncles stout, 1'-6' high; involucre and involucels of broad membranous somewhat united veined bracts; umbels 1'-2' broad in fruit; rays several, 3"-9" long; pedicels 1"-2" long; fruit ellipsoid, 3"-6" long, the carpels broadly 3-5 winged; oil-tubes 1-3 in the intervals.
Dry soil, South Dakota to western Nebraska, Wyoming, Colorado and Texas. March-April.