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      William Weber and the authors of the new Brassicaceae volume of The Intermountain Flora have indicated for several years that even though the Old World Arabis and our New World Boechera are morphologically nearly identical, genetically they are distinct and the several species pictured below should be called Boechera, not Arabis.  The authors of Intermountain Flora indicate, "The morphological similarities appear to be due to convergent evolution, a curse with which the Brassicaceae burdens us."  The authors also indicate that the upcoming volumes of the authoritative Flora of North America will call this genus Boechera not Arabis.  

     Until 2005, the USDA plant database and the Synthesis of the North American Flora accepted the genus name "Arabis", not "Boechera".  John Kartesz's Synthesis now accepts Boechera as the genus name. 

Tyge Boecher was a 20th century Danish botanist who studied the flora of Greenland.  (More biographical information.)  Boechera is often pronounced "Boo-ker-uh", "Bow-ker-uh", or "Betch-er-uh".  (More biographical information). 

    The genus name, Arabis, was given by Linnaeus in 1753.  Love and Love renamed the genus in 1975 and most botanists now accept this name.

    There are a number of Boecheras in the Four Corners and specific identification  often can only be made by a careful examination of the seeds. 

    See also Boechera sp.
Boechera holboellii
Boechera holboellii.  Synonym: Arabis holboellii. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Behind the Rocks Wilderness Study Area, Utah, April 14, 2009.

Boechera holboellii can grow to over two feet tall with large (for  this genus) flowers.  It has a a cluster of basal leaves, short stem leaves that clasp the stem, and seed pods (siliques) that are up to three inches long and pendulant.  As is true of many Boecheras, flower color ranges through blues and pinks to occasional whites. All the Boecheras shown on this page share similar Sagebrush and Pinyon/Juniper woodlands habitat.

Carl Peter Holboll (1795-1856) collected this species in 1828 in Greenland.  (More biographical information about Holboll.)

Boechera holboellii

Boechera holboellii.  Synonym: Arabis holboellii. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Behind the Rocks Wilderness Study Area, Utah, April 14, 2009.

Compare the basal leaves of this Boechera with those of the other Boecheras shown on this page.  Notice the caudex, the woody stem.

Boechera holboellii

Boechera holboellii.  Synonym: Arabis holboellii. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Behind the Rocks Wilderness Study Area, Utah, April 14, 2009.

Branching hairs, especially on the basal leave, are characteristic of this species.

Boechera holboellii

Boechera holboellii.  Synonym: Arabis holboellii. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Behind the Rocks Wilderness Study Area, Utah, April 14, 2009.

Stem leaves usually clasp the stem, are overlap the leaf above them (i.e., are longer than the internode), roll inward, and are reduced in size upward. Fruit stems ("pedicels") and fruit ("siliques"  --  very light green/white in the photo) typically droop, as shown here in the upper right of the photograph.

Boechera holboellii

Boechera holboellii.  Synonym: Arabis holboellii. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Behind the Rocks Wilderness Study Area, Utah, April 14, 2009.

Boechera perennans
Boechera perennans.  Synonym: Arabis perennans. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Canyons of the Ancients National Monument, April 5, 2005.

This delicate Boechera grows to be about as tall as B. pulchra, but otherwise is about half the size in leaves, flowers, and seed pods (siliques).  Flower color in both Boecheras ranges through blues and pinks to occasional whites. The two plants share similar Sagebrush and Pinyon/Juniper woodlands.

"Perennans" is from the Latin for "perennial".  This plant was first collected in Arizona in 1881 and was named Arabis perennans by Sereno Watson in 1887.  William Weber named it Boechera perennans in 1982.

Bochera perannans
Boechera perennans.  Synonym: Arabis perennans. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Canyons of the Ancients National Monument, April 5, 2005.

Several characteristics shown in the photo at left help to set this Boechera off from the other Boecheras shown on this page.  The basal rosette is dense and made up of finely toothed leaves, the stem leaves are short and clasp the stem, and the stem leaves have a blue-green tint to them.

Boechera perennans
Boechera perennans.  Synonym: Arabis perennans. (Rockcress)
Brassicaceae (Mustard Family)

Semi-deserts, foothills. Woodlands, shrublands, openings. Spring.
Canyons of the Ancients National Monument, April 5, 2005.

The long, slightly down-turning siliques can be seen in the background and to the left.

Boechera pulchra
Boechera pulchra.  Synonym: Arabis pulchra.  (Rockcress)
Brassicaceae (Mustard Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Negro Bill Canyon, April 1, 2004.

This slender, dainty, and lovely (thus the Latin, "pulchra", meaning "beautiful") member of the Mustard Family grows in open, sunny, semi-desert areas of the Four Corners.  The plant is easily passed by because it is so slender and its flowers are so pale, varying from nearly white to pink to lavender-purple. 

M. E. Jones named this plant Arabis pulchra in 1887 from a specimen he collected in Nevada in 1882, and William Weber renamed it Boechera pulchra in 1982.   

Boechra pulchra
Boechera pulchra.  Synonym: Arabis pulchra.  (Rockcress)
Brassicaceae (Mustard Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Mc Elmo Canyon, April 25, 2009.

Stem and pedicels (flower and fruit stems) are hairy.  Fruits (often called siliques in the Brassicaceae) are more and more pendant as they elongate.

Boechera pulchra
Boechera pulchra.  Synonym: Arabis pulchra.  (Rockcress)
Brassicaceae (Mustard Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Mc Elmo Canyon, April 25, 2009.

Narrow, pubescent leaves are in a loose basal array and are shorter than the stem leaves.  Notice the branched caudex, the woody base of this otherwise herbaceous plant. Other species of Boechera can have tight clusters of basal leaves and no caudex.

Boechera pulchra
Boechera pulchra.  Synonym: Arabis pulchra.  (Rockcress)
Brassicaceae (Mustard Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Mc Elmo Canyon, April 25, 2009.

Boechera pulchra
Boechera pulchra.  Synonym: Arabis pulchra.  (Rockcress)
Brassicaceae (Mustard Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Negro Bill Canyon, April 1, 2004.

Boechera pulchra
Boechera pulchra.  Synonym: Arabis pulchra.  (Rockcress)
Brassicaceae (Mustard Family)

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
Mc Elmo Canyon, Canyon of the Ancients National Monument, March 27, 2005.