Vesper montanus (Torr. & A. Gray) R. L. Hartm. & G. L. Nesom

Cymopterus montanus (Nutt.) T. & G. Fl N. Am. 1: 624. 1840.
Phelloplerus montanus Nutt.; T. & G. Fl. N. Am. 1: 624, as syn. 1840. Leptocnemia campestris Nutt.; T. & G. Fl. N. Am. 1: 624, as syn. 1840. Cymopterus campestris T. & G. Fl. N. Am. 1: 624. 1840. Phellopterus macrocarpus Osterhout, Muhlenbergia 6: 59. 1910.
Plants acaulescent or subcaulescent with the development of a pseudoscape, 5-30 cm. high, from long fusiform or subfusiform roots; leaves ovate-oblong in general outline, excluding the petioles 1.5-8 cm. long, 1-6 cm. broad, pinnate, bipinnate, or occasionally ternate-bipinnate, somewhat fleshy, pallid, the leaflets entire to pinnately lobed, the lobes usually obtuse, mucronate, 1-2 mm. long, 0.5-1 mm. broad, confluent, roughened on the margins and veins; petioles 1-14 cm. long; peduncles shorter than or equaling the leaves, 0.5-10 cm. long, minutely roughened throughout or only at the base of the umbel; involucre of a low inconspicuous sheath, or of conspicuous linear-oblong bracts, or wanting; involucel of conspicuous, ovate-oblong, mostly acute bractlets, sometimes lacerate toward the apex, white with a conspicuous green central nerve, usually shorter than the flowers, the umbels subcompact; fertile rays 3-6, slightly spreading, 0.5-20 mm. long, glabrous or minutely hirtellous, the secondary' rays short; pedicels 2-5 mm. long; flowers white or purple; fruit ovoid to ovoid-oblong, 5-12 mm. long, 4-10 mm. broad, the wings conspicuously enlarged at the base, narrowed toward the apex, twice as broad as the body; oil-tubes 1-4 in the intervals, 2-6 on the commissure, accessory oiltubes occasionally present in the wings; strengthening cells present in the wing-base, or wanting.
Type locality: "High bare plains of the Platte, towards the Rocky Mountains," Nuttall. Distribution: South Dakota and central Colorado to northwestern Texas and northern New