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 Idaho Mountain Wildflowers

Mustard, or Cabbage Family: Brassicaceae

The scientific family name Brassicaceae is derived from the Latin brassica, a word that means “cabbage.” (An older family name, Cruciferae, is still in use although most botanists prefer the former name.) The family contains many valuable food plants rich in vitamin C and sulfur compounds—the latter are responsible for the typical smell and taste of foods such as cabbage, brussel sprouts, broccoli, turnip, and mustard (all of which belong to the genus Brassica ), water cress (Rorippa spp.), radishes (Raphanus spp.), and many others. While these are of great economic importance, the family also contributes ornamentals to our gardens: ornamental cabbages, wall-flowers (Erysimum spp.), rockcresses (Arabis spp.), and others. The flowers’ four petals usually form a cross, explaining the older family name Cruciferae, derived from the Latin crus (cross) and fero (I bear) and members of the family are often referred to as “crucifers.” The flowers are frequently borne in clusters (“racemes”). Leaves are usually simple, alternate, and lack a petiole (a leaf stem). Most of the Brassicaceae form seedpods. When these are long, they are “siliques”; when short, they are known as “silicles.” The leaves and other parts of the plants often have a radishy taste. Members are represented in our mountains by several genera and many species, including some with showy flowers, as shown on the following pages. Most likely any small, four-petaled, early spring-blooming wildflower will belong to the mustard family.

	Draba species: The drabas are the largest genus in the mustard family with about 350 species. The name, from Greek antiquity, was used for a now unknown crucifer.  “Whitlow grass” is an old English name for drabas because they were used as poultices  to treat “whitlows,” or “run-arounds”—infections at the base of the nails. At lower altitudes drabas tend to be long-stemmed solitary plants with small white, pink, or yellow flowers. At higher elevations, they form compact clumps on rocky slopes, usually flowering at the end of snowmelt. . Some are localized to one area or mountain range. These plants are so alike that species identification is difficult. Few-seeded draba, Draba oligosperma Hook. (left). The species name, oligosperma, means “few seeds.” The few-seeded draba grows in all but the most southern of our western mountain states and in Canadian provinces, from lower elevations to subalpine slopes. While its flowers are similar to other plants shown on this page, its narrow leaves do not form mats. Payson’s draba, Draba paysonii J. F Macbr.  (right). Payson’s draba is found only at high elevations in the Sierras, and northern Rocky Mountains in the United States and Canada. The plant shown here was photographed well above treeline on Mount Borah, Idaho’s highest mountain. Its tiny, hairy, clustered leaves grow at ground level and remain well hidden when the plants are in flower. Two varieties are recognized; ours is var. treleasii (O. E. Schulz) C. L. Hitchc.
	Stanley Creek draba, Draba trichocarpa Rollins. (left) The Stanley Creek draba has the most restricted range of any of the very similar alpine/subalpine plants shown on this page, for it is found only near Stanley, Idaho. Because this species was described relatively recently it is often not listed in regional plant guides. Its four-petaled flowers are small and remain partially closed, and its tiny leaves form tight clusters. The species name, trichocarpa, means “hairy fruit.” Globe-fruited draba, Draba sphaerocarpa J. F. Macbr. & Payson. (right). This cushion-forming plant,grows only on exposed alpine and subalpine ridges of the Sawtooth Mountains. Its common and species names both refer to its rounded fruit. While many draba species are quite similar, tentative identification is sometimes possible based on plant location and appearance. Definitive identification usually depends on technical differences among the fruits of various species.
	Lance-leaf draba, Draba cana Rydb. (left). The lance-leaf draba (also known as the cushion whitlow-grass) blooms later in the spring than do those shown above, favoring high open slopes and rocky crevices. This plant’s classification has been a source of confusion in the past. It has variously been classified as Draba lanceolata or as Draba breweri. The classification used here is correct. The plant is found throughout the Rocky Mountains to Alaska, east across the continent to several northern states, and south to California, Nevada, New Mexico, and Utah. It also grows in Greenland and Eurasia. Spring whitlow-grass, Draba verna L. (right).The spring whitlow-grass is an imported European weed that has spread throughout much of the Northern Hemisphere. It is found throughout Idaho. It is easily identified by clustered bright-white flowers. The flowers are unusual for they have two pairs of opposed, deeply cleft petals—a feature that serves to identify the plant

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