E-Flora BC: Electronic Atlas of the Flora of British Columbia

Arabis pycnocarpa M. Hopkins
blushing rock-cress
Brassicaceae (Mustard family)

Introduction to Vascular Plants

© Curtis Bjork  Email the photographer   (Photo ID #46920)

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Distribution of Arabis pycnocarpa
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Arabis pycnocarpa var. pycnocarpa

Species Information

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Biennial or short-lived perennial herb from a simple stem-base; stems usually simple, 15-100 cm tall, strongly stiff-hairy at the base, usually glabrous above.
Basal leaves oblanceolate, 2-8 cm long, 1-1.5 cm wide, narrowed to a fringed, winged stalk, often purplish beneath, glabrous to hairy, remotely toothed; stem leaves broadly egg-shaped, 2-10 cm long, 1-3 cm wide, broadly unstalked, usually ear-like at the bases and clasping.
Racemes few to many flowered; petals 4-9 mm long, white to cream or pale pink; outer sepals bulging on one side at the base.
Siliques, erect, tightly appressed to the axis of the inflorescence or angled slightly outward, 4-8 cm long, 0.75-1.5 mm wide; seeds in 1 row, 1.5 mm long, with narrow wings.
All of our BC material is referable to the var. pycnocarpa (Hopkins) Roll., except for a single collection of the European var. hirsuta, from Glacier National Park.. The two varieties may be separated as follows:

1. Plants perennials; siliques beakless.......................... var. hirsuta

1. Plants biennials or short-lived perennials; siliques with a beak 0.5-1.25 mm long........................... var. pycnocarpa (Hopkins) Roll.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist to mesic meadows, gravel bars, open woods, rock outcrops and waste places in the lowland and montane zones; var. hirsuta known in BC only from Glacier National Park; var. pycnocarpa common throughout BC east of the Coast-Cascade Mountains; circumpolar, S to CA, NM and GA; Eurasia.

Source: The Illustrated Flora of British Columbia

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References