Kellogg spurred lupine as seen on rocky slopes at the southeastern corner of Strawberry Mountain, Strawberry Mountain Wilderness..........August 3, 2011.
Kellogg's spurred lupine is an attractive perennial wildflower with an unsettled taxonomy. It is very similar in appearance to spurred lupine (Lupinus laxiflorus) as well as the spurred forms of silvery lupine (Lupinus argenteus var. heteranthus), and is easily confused with both the latter species. Complicating matters is the fact that these species are often found together. I've recently read in Peck's "Manual of the Higher Plants of Oregon" that additional species may be spurred, including sulphur lupine, Lupinus sulphureus and whitish lupine, Lupinus leucopsis.
Hitchcock, in his "Flora of the Pacific Northwest" classifies Kellogg's spurred lupine as Lupinus caudatus. Current nomenclature lists it as either Lupinus arbustus ssp. neolaxiflorus or Lupinus argenteus ssp. heteranthus. I'd imagine the taxonomy of this species is still being considered and perhaps open for further revision.
The several stems of Kellogg's spurred lupine range from simple to branched and range from 20-35 cm tall. The herbage consists of silvery, silky, straight hairs closely appressed to the stem or leaves, all pointing in the same direction. Basal leaves may or may not be present. If so, the petioles range from 2-2.5 times longer than the blades. The petioles of the upper stem leaves are usually shorter than the leaf blades. Individual leaves are palmately compound with 6-10 leaflets, each of which ranges from narrowly to broadly oblanceolate. Individual leaflets range from 3-5 cm long with pointed tips and with silky hairs on both leaf surfaces.
The racemes range from 5-30 cm long with many flowers. Spacing of the flowers ranges from closely packed (somewhat reminiscent of Lupinus leucophyllus) to widely spaced. The flower stems range from 2-3 mm long. Individual flowers are 10-12 mm long. The calyx which measures 3-4 mm long is slightly to prominently spurred on the upper side above the petiole. The upper calyx lobe is split at its tip, and ranges from 1/3 to 3/4 the length of the wings of the corolla (See photo below.). The corolla ranges from blue, purple, pink or white in color. The banner often is marked with white or yellowish on the front and has some short hairs on its back. The wings are glabrous (as opposed to being minutely pubescent on their upper surface as in Lupinus arbustus) or entirely lacking hairs. The margins of the keel are fringed with minute hairs. The silky pods are 2-3 cm long. The 4-6 seeds are about 5 mm long and a pinkish-brown in color.
The taxonomy of the spurred lupines has changed a number of times over the course of the past 10 years. This list attempts to differentiate between the spurred lupines, whether they have been lumped into a single unit as some have suggested or whether they are separate entities.
Silvery Lupine: Lupinus argenteus var. heteranthus - Back of banner sparsely hairy or glabrous. When present, hairs may be largely hidden by the upper calyx lip. Flowers 5-10 mm long with the banner index from 4-9. Wing petals not pubescent near the tip, although sometimes hairs may be present along the midvein. Basal leaves generally absent when in bloom, but if present, the pedicels are less than three times as long as the leaflets. Found from Lake County in south-central Oregon and the Steens Mt. of southeastern Oregon and south to Mono county in California and east to western Nevada.
Kellogg's Spurred Lupine: Lupinus caudatus (now L. argenteus var. heteranthus ) - Back of banner typically pubescent on lower 2/3 of banner. Flowers 10-12 mm long, the banner index measuring from 5-10. Wing petals not pubescent near tip. Upper calyx lip nearly as long as the lower lip, measuring 1/3-3/4 as long as the wings. Found east of the Cascade Mts. from central Oregon south to California and east through Idaho to Montana and Colorado.
Spurred Lupine: Lupinus arbustus (former Lupinus laxiflorus) - Back of banner typically pubescent on lower 2/3 of banner. Flowers 9-14 mm long, the banner index from 4-9. Wing petals pubescent near tip. Upper calyx lip much shorter than the lower lip, only 1/5-14 as long as the wings. Found in and to the east of the Cascade Mts. from central Washington south through Oregon to California and east to Idaho, Utah and Nevada.
Sulphur Lupine: Lupinus sulphureus - Back of banner glabrous or sparsely pubescent, especially under the upper calyx lip. Typically not spurred, but if spurred, the spur is short. Flowers 9-12 mm long, the banner index from 4-10. Basal leaves generally present while in bloom with pedicels 3-5 times longer than the leaflets. Found east and west of the Cascade Mts. from south-central British Columbia south through central Washington and Oregon to California and east to Idaho.
Kellogg spurred lupine may be found in ponderosa pine forests and in the sagebrush desert from the foothills into the lower mountains.
Kellogg spurred lupine is found east of the Cascade Mountains from central and eastern Oregon south to California and eastward to Idaho, Montana, Wyoming and Colorado.