Lupinus bicolor

From Puget Prairie Plants
  • Scientific Name: Lupinus bicolor
  • Family: Fabaceae
  • Common Names: field lupine, small-flowered lupine, two-color lupine
  • Synonyms/Misapplications: Lupinus hirsutulus, L. micranthus, L. polycarpus, L. strigulosus
  • Codon: LUPBIC

Photo by Ben Legler, 2004, also featured on Main Page


Scientific classification
Kingdom: Plantae
Subkingdom: Viridiplantae
Phylum: Tracheophyta
Subphylum: Spermatophytina
Class: Magnoliopsida
Subclass: Rosanae
Order: Fabales
Family: Fabaceae
Genus: Lupinus L.
Species: Lupinus bicolor Lindl.



Native taprooted annual, up to 4 dm tall.

Leaves are alternate, palmately compound with 5-8 leaflets, appressed hairy on one or both sides.[2]

Produces one, sometimes branched, flowering stem, on which flowers are scattered, not whorled.[2] Papillonaceous flowers are pale blue to deep purple, with a white area on the banner, often with blue or purple spots, which turns magenta after pollination.[3] The keel is white, generally pointed, with ciliate upper margins.[4][5]

The pods are appressed-hairy, bearing 4-8 seeds.[2]

Bloom Period

April to July.[3]


Chiefly west of the Cascades in Washington state, but also in southeastern part of state via the Columbia River Gorge; British Columbia south to California, east to Arizona.[5]


Open, gravelly and sandy sites, prairies.[5]


Important nectar source for bees.[6]

Host plant for the Arrowhead Blue butterfly.[7]

According to Welch, there is documentation of Northern Pomo use as food, the whole plant, except the roots, baked and eaten as greens, and young greens eaten fresh.[8]

Several species in the Lupinus genus are important food plants.


Lupinus bicolor seeds, photo by Lisa Hintz

Seed sample from: 2011

Average Measurement: 2.4 x 1.9 x 0.9

Measurement Range: L: 2 - 3, W: 1.75 - 2.25, D: 0.75 - 1


Color: Seeds mostly brown, speckled with brown, gray, off-white, and/ or black. Seeds have distinctive black splotchy line that crosses the lateral seed face to encircle the hilum, inside of which is another similar white line. Seed edges are less heavily speckled with dark colors, giving them a more off-white appearance.

Surface: Seed surface smooth and glossy, with some small concave pockets.

Latitudinal Cross Section: elliptical LUBI-lat-crosssection.png

Longitudinal Cross Section: elliptical LUBI-long-crosssection.png

Basic Explanations and Assumptions:

The dimensions for the seeds are length x width x depth. The location of the hilum is used as the base of the seed, and the length is measured from hilum to the opposite apex. Where a style is present, the length is measured from the hilum to the bottom of the style. Width is measured at a right angle to the length at the widest part. Depth is measured at a right angle to the intersection of height and width lines.

Measurements included are the mean average for each measurement of ten separate seeds.

All measurements in millimeters unless otherwise noted.

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  1. Integrated Taxonomic Information System. Retrieved from
  2. 2.0 2.1 2.2 In Klinkenberg, Brian. (Editor) 2020. E-Flora BC: Electronic Atlas of the Plants of British Columbia []. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2020-06-08 12:03:17 PM ]
  3. 3.0 3.1 Bowcutt, F., & Hamman, Sarah. (2016). Vascular plants of the South Sound prairies (First ed.). Olympia, Washington: The Evergreen State College Press.
  4. Teresa Sholars & Rhonda Riggins 2012, Lupinus bicolor, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=31793, accessed on June 08, 2020.
  5. 5.0 5.1 5.2 Hitchcock, C. L., Cronquist, A., Giblin, D., & Legler, B. et al. (2018). Flora of the Pacific Northwest: an illustrated manual. Seattle: University of Washington Press.
  6. Plant Database. Lady Bird Johnson Wildflower Center - The University of Texas at Austin. (2018, November 30).
  7. Miniature Lupine, Lupinus bicolor. California Native Plant Society.
  8. Welch, J. R. (2013). In Sprouting valley historical ethnobotany of the northern pomo from Potter Valley, California (pp. 87–87). essay, Society of ethnobiology.