Kellogg's Spurred Lupine

Lupinus caudatus is a cool-season herbaceous perennial plant. It develops a thick, deep taproot topped with a woody structure at the base of the stems at the top of the root at or just below ground level (a caudex). From this caudex it has flowering stems that may be branched or unbranched. Most of its leaves grow on individual leaf stems at the base of the plant (basal leaves) which are 6–10 centimeters (2.4–3.9 in) long. Each leaf is divided into 5–10 smaller leaflets attached together at a central point forming a rounded fan (palmate compound). The leaflets are most often 2–4 cm (0.8–1.6 in) long, but may occasionally reach as much as 6 cm (2.4 in). They are 4–8 millimeters wide and are narrow with a shape like reversed spear point, wider nearer the end than at the base (linear-oblanceolate) with a sharp point with the leaf rib extending slightly beyond the leaf margin at the tip (mucronate). The leaves are densely covered by fine hairs that lay flat on both the upper and lower surfaces giving them the appearance being covered in combed silk (sericeous) and the sides of the leaflets often bend inwards until they almost touch (conduplicate). Lupinus caudatus has flowering stems that are 20–80 centimeters tall depending on local conditions. The stems may be branched or unbranched and end with a 4–10 centimeter long inflorescence (terminal raceme) with many flowers. …

Lupinus caudatus is found throughout the western United States from the Rocky Mountains to the Sierra Nevadas and Cascades from occurrences recorded in the PLANTS database. It also records it in the Texas panhandle, Oklahoma, Nebraska, and South Dakota. The Global Biodiversity Information Facility (GBIF) also has a record of the single undated preserved specimen from Alberta, Canada. GBIF also has numerous specimens records from Mexico under the synonymized name Lupinus lupinus collected from the states of Baja California, Baja California Sur, and Durango. POWO also records it growing in North Dakota, but lacks records of it growing in Washington State, Nebraska, South Dakota, Oklahoma, Texas, or any part of Mexico. The usual habitat for Lupinus caudatus is moderately dry, well-drained soils. It is a common feature of open hillsides and road cuts, and will occasionally be found in moderately moist meadows. It will grow with sagebrush or in open timber stands, it is especially noted for being found with the ponderosa pine (Pinus ponderosa). Other habitats where it can be found include desert scrub and mountain or foothill chaparral. It is a fairly common plant in much of its range and is often found in great numbers locally. Its approximate maximum elevation is about 3150 meters in Colorado and minimum is 1450 meters in Utah.

Conservation. …

Lupinus caudatus is eaten by elk, mule deer, whitetail deer, antelope, upland game birds, small non-game birds, and small mammals. Observational studies have not found native wild animals to be poisoned by it. For pocket gophers on the Columbia Plateau in June, it is a very important source of forage. More than two-thirds of all the forb shoots consumed were observed to be of this species and the leaves were also readily consumed in one study. Because it is one of the more palatable Lupinus species, it is also eaten by sheep, cattle, and horses, sometimes to their detriment. While it will also persist in mature landscapes, Lupinus caudatus is generally increased by disturbances. Many plants will survive wildfires and in the next season will set seed to recolonize the open landscape. While they are good at colonizing open ground and low fertility soils, they lack a dense mat of roots and so are ineffective at preventing erosion in disturbed landscapes.