Perennial Rockcress Flower Perennial Rockcress Flower Perennial Rockcress Stem Perennial Rockcress Stem Perennial Rockcress Leaves Perennial Rockcress Plant Sabino Canyon 2/8/22 Perennial Rockcress Flower Sabino Canyon 2/8/22 Perennial Rockcress Plant

Wildflowers of Southern Arizona

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Perennial Rockcress.
Boechera (Arabis) perennans.
Mustard (Brassicaceae) family.

Duration: Perennial. Nativity: Native. Lifeform: Subshrub. General: Long-lived perennial herbs, 15-70 cm tall, from a woody caudex; stems usually 2-5 per caudex branch, arising laterally just below leaf rosettes or sterile shoots, often elevated above the ground surface on woody base; lower portions of stems densely pubescent mostly with y-shaped hairs (i.e. a short stalk forking into 2 branches); upper stems usually glabrous. Leaves: Basal leaves petiolate, clustered in distinct rosettes; stem leaves alternate, sessile; basal blades oblanceolate to obovate, 3-20 mm wide, margins dentate, surfaces moderately to densely pubescent with stalked, 3-6 rayed stellate hairs; stem leaves few, clasping the stem with auricles 0.5-3.5 mm; uppermost stem leaves hairless. Flowers: White to purple, in terminal racemes of 16-35 flowers, on 1-2 cm pedicels which are ascending in flower and horizontal in fruit; sepals 4, pubescent; petals 4 in a cross formation, white to purplish, 5-9 mm long and 1 mm wide. Fruits: Capsules linear, 3-7 cm long and 2 mm wide, usually curved, widely pendent, glabrous; seeds 1 mm long, 1 mm wide, winged, in one row per locule. Ecology: Found on rocky slopes and gravelly soil in warm desert, chaparral, and low montane habitats, below 6,000 ft (1829 m); flowers February-May. Distribution: AZ, CA, NV, NM, TX, UT; south to n MEX. Notes: Host plant for the Sara Orangetips butterfly.

Because of hybridization, polyploidy, and self-fertilization, Boechera is an extremely problematic group. There have been several re-organizations of this group over the years (including splitting it out from the genus Arabis). For simplicity it is better to use a recent treatment to identify your plants; this description is based on the Flora of North America treatment (2010) and the key divisions in the Flora Neomexicana (Allred and Ivey 2012). B. perennans is a fairly common early-flowering perennial in the warm desert regions of the southwest. One of its distinguishing features is that it often develops a footlike extension of the caudex between the basal leaves and the ground, appearing to be the consequence of shedding the basal leaves from the previous season. It is most similar to B. gracilenta; it is distinguished by the woody base that elevates the stems and basal leaves above the ground; the toothed margins on the basal leaves; and the mostly y-shaped hairs on the lower portions of the stems; and the seeds in one row per locule. Ethnobotany: Used to treat hiccoughs caused by dry throat; to counter the effects of a bad dream; and taken or made into a lotion to treat general body pain. Etymology: Boechera is named after Tyge Wittrock Boecher (1909-1983), born in Copenhagen, an authority on Arctic vegetation and the flora of Greenland who also worked in Argentina; perennans means perennial.

Santa Catalina Mountains
Prison Camp
Location: Arizona trail 0.1 mile beyond campground road.
3/18/17, 3/19/17

Notes: Sabino Canyon beside main shuttle road between 3rd and 4th bridges 2/9/22

See SEINet Pictures and Description

See FireFly Forest Pictures and Description

Thumb: Tansy Mustard
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