Arabis pycnocarpa var. pycnocarpa

General:
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.

Leaves:
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.

Flowers:
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.

Fruits:
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.

Notes:
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