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Montana Field Guide

Montana Field Guides

Tower-mustard - Turritis glabra
Other Names:  Tower Rockcress, Arabis glabra

Non-native Species

Global Rank: G5
State Rank: SNA

Agency Status
MNPS Threat Rank:
C-value: 1

External Links

General Description
Taprooted annual or biennial (monocarpic) with an unbranched caudex. Stems usually unbranched, 40–120 cm. Vestiture of simple or branched hairs on basal leaves and stem base, glabrous above. Basal leaves petiolate, oblong, shallowly dentate, 2–10 cm long. Stem leaves lance-shaped, auriculate, strongly clasping. Inflorescence an unbranched raceme. Flowers white; petals 4–6 mm long. Fruits siliques 5–10 cm × 1–1.5 mm, nearly terete, strictly erect (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Montana Range


Range Comments
Circumboreal; widespread in North America. Apparently native in parts of the U.S. and Canada, but may be introduced in other parts.

Possibly introduced in parts of Canada (Moss, 1994). Native in the U.S. but apparently introduced from southern Alaska-Yukon-District of Mackenzie-British Columbia-Alberta to Saskatchawan, Manitoba, Ontario, Quebec, and perhaps New Brunswick (Scoggan, 1978). Rare in North Carolina and Virginia; possibly introduced there (Weakley, 2000).

Observations in Montana Natural Heritage Program Database
Number of Observations: 156

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Disturbed or sparsely vegetated soil of streambanks, meadows, grasslands, open forest; plains, valleys, montane (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

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Citation for data on this website:
Tower-mustard — Turritis glabra.  Montana Field Guide.  .  Retrieved on , from