Ragged Rock Flower

Crossosoma bigelovii

Crossosoma bigelovii pen and ink © by Michael Plagens

a) newly opened flower, b) unopened bud, c) mature fruit with three distinct carpels.

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flower of Catalina Crossosoma

A related species, perhaps accidentally introduced to the White Canyon area of Pinal Co., is native to coastal Southern California. Follow the thumb link above for more information.

RANGE: Steep, north-facing mountain sides or within deep narrow canyons across southern Arizona. Often growing straight out of crevices in solid-looking rock.


SHRUB: Flexible branches may reach 2.5 m., but are typically much shorter.

flower of Ragged Rock Flower, Crossosoma bigelovii FLOWERS: Showy, often fragrant, white flowers with five petals. Blooms early in year, usu. Jan. to Mar.

FRUIT: 2 to 5 erect, separate ovaries develop from each flower. Later, these mature into dry capsules each with several seeds.

LEAVES: Elliptic and small, 3 cm or less.

When Crossosoma is blooming, Orange-tip Butterflies are also on the wing in the Sonoran Desert. The Sara Orange-tip (Anthocharis sara) has the base color white and the wing tips orange. The Pima Orange-tip (Anthocharis pima) has the base color yellow, and again wing tips are orange. The butterflies feed as caterpillars on winter and early spring mustards that grow about the same time that Ragged Rock Flower is blooming.

Family: Crossosomataceae

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ragged rock flower, Crossosoma bigelovii, photo © by Michael Plagens

Ragged Rock Flower growing from crevices in a rocky ledge at South Mountain, Phoenix, Arizona.

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Copyright Michael J. Plagens, page created 6 Nov. 2007
updated 10 June 2014.