Plant of the Month: Silver Lupine
Silver Lupine Lupinus albifrons
Global Ranking: G5 see individual varieties below.
Other Common Names: Bentham's Bush Lupine, Silver Bush Lupine
Lupinus albifrons var. abramsii: Abram's lupine, prostrate silver bush lupine G?T? included CNPS inventory of rare & endangered plants. CA (This low variation is now considered a separate species: L. abramsii).
Lupinus albifrons var. albifrons: silver lupine G5T5 CA
Lupinus albifrons var. collinus: silver lupine G5T4? CA
Lupinus albifrons var. douglasii: Douglas' silver lupine G5T4 CA
Lupinus albifrons var. eminens: silver lupine G5T4?Q CA, OR
Lupinus albifrons var. flumineus: silver lupine G5T2T4Q CA, OR
Range:
Silver Lupines are narrowly distributed along the west coast of California and, for some taxa, sourthern Oregon. It is generally found on dry hillsides and canyons and in the Sierra Nevada foothills, between an elevation of 1000 - 3000 ft.
This semi-woody plant grows to a height of 3ft (1m), thriving in arid steeply sloping hillsides. As a legume it is able to fix nitrogen from the air. Its deep roots can travel up to 20 ft (6m) through rock fissures in search of moisture. Its fragrant flowers range from pale pink to dark purple.
Plant Communities:
Silver lupines are found in valley grassland, sagebrush scrub, yellow pine forest & central oak woodland.
Wildlife:
Silver lupines are one of only three species of lupine (also Lindley varied Lupine (L. varicolour); and Summer Lupine (L. fomosus)) that host the endangered Mission Blue Butterfly (Icaricia icariodes missionensis) which is found only in the Twin Peaks area of San Francisco; Fort Baker in Marin County; and San Bruno Mountain in Mateo County, CA.
Like the Great Lakes Region Karner Blue Butterfly (Lycaeides melissa samuelis, now extirpated in Ontario), the Mission Blue has a symbiotic relationship with ants. During the caterpillars spring feeding period, caretaker ants ride on the larvae's back and harvest a sugary secretion while protecting the caterpillar from predators and parasites.
Photo by Pete Veilleux, East Bay Wilds
