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White-bract Blazing Star

Mentzelia involucrata

White-bract Blazing Star, Mentzelia involucrata, photo © by Michael Plagens

This White-bract Blazing Star was found in bloom on the slopes of Stewart Mountain just north of the Salt River in eastern Maricopa County, Arizona, USA on 27 March 2010.

ANNUAL: Spring annual appearing in years after good winter rains. Generally less than 30 cm tall.

FLOWERS: The petals are pale yellow to almost white. Just below the flower are about five enlarged, white and green bracts (modified leaves). Stamens numerous - under good magnification the tips of the stamen filaments are flared out and have a pair lobes on either side of the stamen. Blooming mid to late spring depending on available moisture.

LEAVES: Leaves are variously lobed; generally the lower leaves are larger and with longer lobes.

RANGE: Occurs sporadically on rocky slopes in the Sonoran Desert. Ranges into California and Nevada.

FRUIT: The seed pods, roughly 20 mm in length, develop below the flower and are straight. Numerous small seeds.

UNARMED: No spines or thorns.

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Copyright Michael J. Plagens, 1999-2010