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Coulter's Lupine

Lupinus sparsiflorus

Coulter's Lupine, Lupinus sparsiflorus, photo © by Michael Plagens

Photographed in Maricopa County, Arizona, USA, March 2008. Notice also that there is an irridescent, blue-green, Blister Beetle (Meloidae, Lytta) on the flowers.

ANNUAL: Ephemeral herb of the Sonoran Desert spring. Blooming by mid spring (Feb.) in years with adequate rainfall. Absent in drought years. Most plants less than ½ meter tall. Grows erect.

FLOWERS: Dark blue-purple pea flowers sometimes with the wing petals, hood or entire flower tinged with pink and white. The flowers appear on a verticle spike and open mostly February to April.

LEAVES: Leaves are palmately compound with the narrow leaflets arranged radially. Fairly dense with silky hairs on both upper and lower surfaces.

RANGE: Frequent throughout the Sonoran Desert in Arizona and Mexico at roadsides, on rocky slopes and along washes.

FRUIT: Bean capsules split open explosively as each valve twists in opposite directions - the ten or so bean-seeds are thus ejected a meter or more away from the parent plant. This is fun for students to observe and ask questions about: just set up a couple of flowering spikes in vase with water and wait several days as pods mature and pop open.

UNARMED. No thorns.

Fabaceae -- Bean Family

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Copyright Michael J. Plagens, 1999-2010