Monday, July 8, 2013

Brewer's lupine in the sub-alpine region of North Tahoe

Brewer's lupine (Lupinus breweri) inflorescence

Brewer's lupine (Lupinus breweri) grows in masses on dry, rocky flats below timberline throughout Tahoe [1]. The plants shown here were found along the Tahoe Rim Trail (TRT) around Tamarack Peak and Relay Peak. Especially, the trail section between the Mt. Rose Summit Trailhead and the waterfall, on which the TRT coincidences with the Mt. Rose Trail, leads across forest openings with eye-catching, silver-green mats of low-growing Brewer's lupines. In addition to northwest Nevada, this lupine species is native to parts of California and Oregon—particularly mountain forests [2-5].

The picture above shows a raceme densely populated with blue flowers. Each flower has a white patch on its banner. The flower racemes rise slightly above the basal leaves, each of which being composed of five to ten silky-hairy leaflets. The picture below demonstrates leave and flower size by having a penny placed inside a mat. Due to its carpeting growth pattern, Brewer's lupine is also named matted lupine. Several variations of Lupinus breweri are known [2].

Mat of brewer's lupine (Lupinus breweri) with racemes of flowers

References and more to explore
[1] Laird R. Blackwell: Tahoe WildflowersA Month-by-Month Guide to Wildflowers in the Tahoe Basin and Surrounding Areas. A Falcon Guide, Morris Book Publishing, LLC, 2007; page 62. 
[2] Encyclopedia of Life: Lupinus breweri [eol.org/pages/640971/overview].
[3] iNaturalist: Brewer's Lupine (Lupinus breweri) [www.inaturalist.org/taxa/77853-Lupinus-breweri].
[4] USDA PLANTS Profile: Lupinus breweri A. Gray, Brewer's Lupine [plants.usda.gov/java/profile?symbol=LUBR3]. 
[5] Jepson Manual: Fabaceae, Legume FamilyL. breweri A. Gray [ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?3691,4023,4048].

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