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Mountain Wildflowers

Mustard Family: Brassicaceae
Confusingly, many plants classified in the genus Arabis, have, on the basis of recent DNA studies, been reclassified as Boechera. All of the plants on this page are now in this genus. The name honors a prominent Danish botanist, Tyge Wittrock Böcher (1909-1983).

Hoary rockcress, Boechera puberula (Nutt.) Dorn. (Previously Arabis puberula Nutt.) This little plant (left), has the species name puberula, a word that described the minute hairs  that coat its leaves, explaining their gray-green color. It grows to mid-elevations in our mountains. The generic name Boechera honors Danish botanist Tyge W. Böcher (1909-1983).The chances are that any pink-to-purple, spring-blooming, four-petaled plant found in our mountains will be in this genus

Wind River rockcress, Boechera williamsii (Rollins) Dorn var. saximontana (Rollins) Dorn (right). This plant until recently was classified as Arabis microphylla Nutt. var. saximontana Rollins. It is an uncommon, tiny plant only an inch or so high characterized by smooth surfaced basal leaves, few-leaved stems and small clusters of pink-to-purple four-petaled flowers. Look for it shortly after snowmelt, close to treeline. Two varieties are recognized. One, var. williamsii, is found only in Wyoming where the species was first collected. The other, this plant, grows in Idaho, Wyoming, and Montana.


Cusick’s rockcress, Boechera cusickii (S. Watson) Al-Shebaz (left). Cusick’s rockcress (formerly Arabis cusickii S. Watson ) grows only in Idaho, Nevada, Washington and Oregon. Its tiny flowers range from purple to nearly white. The plant may be identified by its clustered flowers, leafy stems and pendulous fruiting bodies or “siliques” (not present in the illustration). Its silvery-green color comes from fine hairs that cover the foliage. William Conklin Cusick (1842-1942) was an Oregon school-teacher, rancher, and botanist who collected and described many plants native to Oregon’s mountains.

Lemmon's Rockcress, Boechera lemmonii (S. Watson) W. A. Weber (formerly Arabis lemmonii, S. Watson)  shown on the right, is a low, small, purple-flowered, sub-alpine to alpine plant found on bare, windswept talus and gravel slopes high in our mountains. John Gill Lemmon (1832-1908) for whom this species was named, fought in the Civil War and survived imprisonment in Andersonville, the notorious Confederate prison. Scarred by his experience, he moved to California in his mid-thirties and apparently found peace as a botanist and plant collector.

Hoelboell's rockcress, Boechera holboellii (Hornem.) A. Löve & D. Löve (formerly Arabis holboellii Hornem). Holboell’s rockcress (left) is widely distributed across northern North America. Many varieties are recognized—the plant shown here is var. secunda (Howell) Dorn. Holboell’s rockcress may be identified at the species level by its pendulous siliques. It is commonly encountered, growing as high as the subalpine zone. The species name, holboellii, honors Danish naturalist, Carl Peter Holboell (1795-1856), a man whose interests apparently varied greatly, for species of birds, molluscs and fish also bear his name.

Nuttall’s rockcress, Boechera nuttallii (B. L. Rob.) Dorn (formerly Arabis nuttallii (Kuntze) B. L. Rob (right) This rockcressis at home from foothills to mid-montane elevations. A thin stem arises from a basal rosette of leaves, topped by a cluster of white to pinkish flowers that form upward pointing siliques. Englishman Thomas Nuttall (1786-1859), one of the greatest of our early botanists, spent years botanizing in the United States and western North America. His Genera of North American Plants appeared in 1818.

Small-leaf rockcress, Boechera microphylla (Nutt.)  Dorn (left) is a tiny-flowered, tall, rather common, early-spring blooming rockcress. As microphylla (small leaf) suggests, it has a cluster of small, lanceolate, basal leaves, and sparse, even smaller, ascending stem leaves. Its long slim fruit (siliques) are upright, helping to identify the plant.

Elegant rockcress, Boechera sparsiflora (Nutt.) Dorn (right) is taller than most plants in this genus, with the characteristic four petals ranging from pink, or more commonly purple. Its long, drooping, sickle-shaped silicles are characteristic. The plant, as one variety or another ranges from B.C. to southern California, east of the Cascade Range to Wyoming and Montana.

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