Sabin's lupine is a pretty distinct lupine, best identified by its yellow flowers. Only one other northwest lupine (sulphur lupine) has the same flower color, and unfortunately it may be found in close proximity.
Sabin's lupine arises from a branched cronw, having several to many stems arising 7-12 dm in height. The stems and both leaf surfaces are usually covered with many straight hairs, pressed against the stem or leaf surface, and pointing in the same direction. Those hairs on the stem may also be yellow-tinged.
The leaves are usually all found on the stem during the blooming period, with the lower leaves having petioles up to twice the length of the blades. The upper leaf petioles will roughly equal the length of the length of the leaflets. The 8-11 leaflets range from 6-12 cm long and 10-15 mm wide.
The racemes of Lupinus sabinii are 1.5-3 dm long, with numerous but not crowded yellow flowers. The flowers range from 15-18 mm long and occasionally may be purple-tinged. The calyx is noticably hairy, not noticeably spurred, with the upper lip shallowly notched (See photo.). The banner lacks hair on the back, or may have a few hairs in the vicinity of the notched calyx tip. The pea pods are about 3-4.5 cm long and 11-15 mm wide, covered with yellowish hairs. The pod typically contains 4-7 pinkish-brown seeds. It usually blooms from late May into early June.
-Closeups of the flowers of Sabin's lupine. Notice the notch or two teeth on the upper lip (green area on photo at the left). Also note that the back of the banner (upper petal) is smooth, and not haired.
The photos above show the leaflets of Sabin's lupine. The upper photo is the dorsal or upper leaf surface, while the lower photo is of the ventral or lower leaf surface.
Sulphur lupine (Lupinus sulphureus var. sulphureus) Sulphur lupine usually has basal leaves present at flowering time. The basal leaves have petioles 3-5 times as long as the leaflets. The flowers of Sulphur Lupine are generally shorter than those of Sabin's Lupine. The flowers of the former plant range from 9-12 mm in length. The banner of Sulphur Lupine is sparsely haired, or not so at all. The upper lip of its calyx is also notched.
Sabin's lupine may be found in open ponderosa pine forests.
Sabin's lupine may be found in the Blue Mts of southeastern Oregon and northeastern Oregon. It usually blooms from late May into early June.
The photo above shows a close-up of the keel and hairy calyx of Sabin's lupine. Note the ring of tiny hairs along the upper margin of the keel. Photographed along Tollgate Lane in the Umatilla NF....................June 27, 2006.
- -The photo above shows three views of Sabin's lupine as seen amongst timber along a road cut near the Umatilla Rim Trail at the eastern edge of the North Fork Umatilla Wilderness........................June 24, 2007. (Click each photo for a larger view.)