Southwest Colorado Wildflowers, Boechera

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 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.

Until 2005, the USDA plant database and the Synthesis of the North American Flora indicated that this species was called Arabis, not Boechera. John Kartesz, of the Synthesis, recently informed me that Boechera is now the accepted genus 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.

Boechera drummondii. Synonym: Boechera stricta, Arabis drummondii. (Rockcress)
Brassicaceae (Mustard Family)

Foothills, montane. Woodlands, canyons. Spring, summer.
Bear Creek Trail, June 14, 2005.

This slender member of the Mustard family begins blooming early and is quite common from mid-to-high elevations. Flowers range from white to pink, but, click here and you will see that they may even appear to be yellow early in their growth. It continues to elongate and flower for many weeks. Flowers are so small and the stem and leaves so slender, that this is an easily passed-by plant.

"Boechera" is for Danish botanist, Tyge Boecher, and "drummondii" honors botanist, naturalist Thomas Drummond who first collected the seeds of this plant in the northern Rockies. Drummond sent the seeds to England where they were sprouted and in 1829 the resultant plant was named Turritis stricta by Graham. Gray renamed the plant Arabis drummondii in 1863, and the plant has undergone dozens of genus and species name changes since then, the latest being Al-Shehbaz's 2003, Boechera stricta. (More biographical information.)

Boechera drummondii. Synonym: Boechera stricta, Arabis drummondii. (Rockcress)
Brassicaceae (Mustard Family)

Foothills, montane. Woodlands, canyons. Spring, summer.
Bear Creek Trail, June 14, 2005.

Flowers, leaves, and two inch seed pods all have a vertical stance.

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

Semi-desert, foothills. Woodlands, shrublands, openings. Spring.
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. Flower color of Boechera pulchra varies from nearly white to pink to lavender-purple. Narrow, light green leaves are mostly basal in tight, grass-like tufts.

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.

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

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

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

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

Boechera perennans. Synonym: Arabis perannans. (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.

Boechera perennans. Synonym: Arabis perannans. (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.