The various species of Boechera are almost always difficult to tell apart.  Some experts believe that the genus needs an entirely new evaluation leading to a new key. I used a number of keys to identify the species shown in this web site and I am reasonably sure that the identifications are correct.      

     Boecheras have a further problem: their genus name has been a subject of debate.  For two centuries "Arabis", a name given by Linnaeus in 1753 to Old World species, was the accepted genus name for all the similar New World plants, including those shown in this web site.  Genetic research by Löve and Löve led them to believe that the Old World genus and the New World genus were not the same and in 1978 they created the Boechera genus.  In 1982 William Weber furthered their work and reassigned almost all New World Arabis species to the Boechera genus. 

    Most botanists now accept Boechera for the New World members of what had previously been called Arabis.  Boechera is the accepted name in Colorado Flora, Intermountain Flora, Flora of North America, The Synthesis, the USDA Plants Database, etc.  But Stanley Welsh has this to say in his 4th edition of A Utah Flora:

Tradition is followed herein in the maintenance of the North American species within the genus Arabis... as opposed to a narrower view in which that genus is shorn of everything in North America [and almost all species are placed in] Boechera.  [I retain the Arabis genus] even though Intermountain Flora and Flora of North America... have fallen in line with the modernists, those who play with numbers until "proper" and hence "correct" results are obtained....  One should not have to [take] a laboratory [to the field] to make determinations of "molecular phylogeny" prior to placement of genera, and at the same time toss away morphological considerations.

     Other botanists agree with what Welsh implies in his last statement: morphologically, the New World species are nearly identical to the Old World species.  Further, as noted above, the New World species are very similar to each other.  The authors of Intermountain Flora indicate, "The morphological similarities appear to be due to convergent evolution, a curse with which the Brassicaceae burdens us."  

     To sum: most botanists believe that laboratory work indicates that the New World species are genetically distinct from the Old World species and that morphological, field characteristics should not take priority in naming the genus.

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

Click to see Boechera afflicted with yellow Puccinia rust.

 Click for more Boechera.

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.   

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.

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.

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

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

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

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Boechera holboellii

Range map for Boechera perennans   

Range map for Arabis pulchra