Oxytropis campestris var. dispar
Oxytropis campestris var. roaldii
field locoweed
roald's locoweed
strongly dimorphic, 5–21 cm;
stipules usually concealed by vesture;
leaflets 19–25, scattered or subopposite, blades primary ones crowded, ovate, shorter, distally linear-lanceolate or narrowly oblong, 4–20 mm.
2–11 cm;
stipules glabrous or strigose abaxially, margins ± ciliate, apex often bristly;
leaflets 11–21, scattered or opposite, blades 4–8.5 mm.
8–15-flowered, ± open to elongate.
usually 8–12(–14)-flowered, subcapitate or somewhat elongate.
7–19(–26) cm, axis 3–8(–11) cm in fruit.
3–12 cm, axis 1.5–4.5 cm in fruit.
purple, blue, pink, white, yellowish, or polychrome (in populations), 17–19(–21) mm.
lavender or pink-purple, sometimes polychrome, 13–16(–17) mm.
tube 6–6.5 mm, lobes 2–2.7 mm.
tube (3.7–)4.5–5 mm, lobes (1–)1.2–2(–2.7) mm.
13–18 × 3.5–5 mm.
9–15 × 4–6 mm.
= 32.
= 64.
Oxytropis campestris var. dispar
Oxytropis campestris var. roaldii
Variety dispar is closely allied to var. spicata, from which it differs in the flowers being polychrome within populations and in the somewhat firmer texture of the pods. It may well be that var. dispar is the somewhat stabilized product of previous hybridization involving the disjunct pale-flowered var. spicata and the purple-flowered Oxytropis lambertii, common in the same region. However, the presence of var. johannensis, not far distant to the northeast, might account for the occurrence of darker colored flowers in this region.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Variety roaldii has flowers that are usually larger, calyx lobes that are usually longer, and other subtle differences aside from flower color that allow segregation from var. jordalii. However, there are intermediate specimens, and in some places, especially on gravel bars, flower color grades within populations. A similar pattern is to be noted between the partially sympatric vars. davisii and spicata in the mountains of Alberta, and between other varieties situated elsewhere. The Pan-Arctic Flora (http://panarcticflora.org/) recognizes Oxytropis roaldii as a distinct species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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