Holboell's Rockcress
Arabis holboellii Hornem.
Family: Brassicaceae, Mustard
Genus: Arabis
Synonyms: Arabis retrofracta
Other names: reflexed rockcress
Nomenclature: holboellii = named after Holboel
Nativity / Invasiveness: Montana native plant
Edible plant
No medicinal data

General: biennial or short-lived perennial, the 1 to several stems simple or often branched above, 10-100 cm tall, with star-shaped hairs, coarse at the base, or densely and uniformly fine-hairy overall, to hairless above.

Leaves: the basal ones usually in a rosette, 1-5.5 cm long, 2-7 mm broad, oblanceolate, entire to short-hairy with star-shaped, coarse to fine hairs, the stalks sometimes hairy on edges. Stem leaves alternate, usually overlapping, entire or occasionally few-toothed, mostly stalkless and with earlike lobes at base or even clasping, narrowly oblong to lanceolate, 1-5 cm long, 2-7 mm broad, short-hairy or sometimes the upper ones hairless.

Flowers: 20 to 100 in a narrow cluster. Flower stalks 5-15 mm long, hairless to short-hairy, abruptly bent down at the base. Sepals 4, 2.5-5 mm long, hairless or hairy. The 4 petals 5-10 mm long, sometimes white to pink but more commonly pinkish-purple. April-August.

Fruits: pods, hairless, linear, 3-7 cm long, 1-2 mm broad, 1-nerved to about midlength, straight or only slightly curved. Style obsolete. Seeds in 1 row or irregularly arranged, 1-1.5 mm long, the wing barely 0.2 mm broad.


From sagebrush and ponderosa pine slopes to well up in the mountains, in most parts of MT. Also from B.C. to CA, CO, NE, MI, and Quebec.
Edible Uses

All rockcresses are edible, with the typical sharp flavor of plants of the mustard family. The tender leaves and flowers are usually added to salads and sandwiches for flavor, but some people like their hot horseradish flavor, and enjoy them alone.

Sub taxa:

1 Stem leaves without earlike lobes at base. B.C. to CA, e. to MT and CO.
var. pendulocarpa (A. Nels.) Rollins

1 Stem leaves with earlike lobes at base, often somewhat clasping

    2 Flower stalks abruptly bent down at the base, rather than curved downward. Pods commonly straight, bent down at the base of the stalk. Basal leaves uniformly finely short-hairy

      3 Lower portion of the stem coarsely hairy with simple or forked to star-shaped hairs. Petals mostly less than 7 mm long, white to pale pinkish. Alberta to WY, e. to Quebec through the Dakotas and Manitoba.
      var. collinsii (Fern. ) Rollins

      3 Lower portion of the stem finely and uniformly short-hairy with small, star-shaped, often flat-lying hairs. Petals mostly over 7 mm long, white to deep pink or purple

        4 Pods mostly 1.5-2 mm broad. Stem leaves usually with rolled down edges, the upper ones generally short-hairy. Basal leaves often felt-textured or at least grayish. B.C. and Yukon to CA, e. to Alberta and CO.
        var. retrofracta (Grah.) Rydb.

    2 Flower stalks more uniformly curved down, the pods drooping, with the tip often somewhat curved in Basal leaves mostly coarsely short-hairy. B.C. to CA, e. to CO and Saskatchewan.
    var. pinetorum (Tidestrom) Rollins

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