Boechera laevigata (Smooth Rock Cress)
|Also known as:|
|Habitat:||part shade, shade, sun; rocky deciduous woods, bluffs, ravines|
|Bloom season:||May - July|
|Plant height:||1 to 3 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Loose, elongating racemes at the top of the plant and sometimes arising from leaf axils in the upper plant. Flowers are less than ¼ inch long with 4 white petals and 6 yellow-tipped stamens. Surrounding the flower are 4 erect light green sepals as long as or slightly shorter than the petals, so just the tips of the petals poke out. The flowers droop down on slender stalks about 1/3 inch long.
Leaves and stems:
Stem leaves are 2 to 6 inches long, narrowly lance-shaped, mostly hairless, toothless or with a few teeth, the lower stem leaves clasping the stem with 2 short lobes at the base (auricles), and are a bit floppy. Upper stem leaves may be stalkless but not clasping or auricled, are more linear and rather shorter than the lower leaves.
Basal leaves are up to 3 inches long, more spatula shaped on short stalks, the surfaces slightly glossy, smooth or sparsely hairy, with small sharply pointed teeth around the edges and rounded tips. Stems are smooth. Leaves and stems are green, green tinged purple, or dark purple.
Smooth Rock Cress, formerly known as Arabis laevigata, vaguely resembles the much more common Spreading-pod Rock Cress (Boechera grahamii), which has flowers larger than ¼ inch, shorter, stiffer leaves, and roughly hairy basal leaves. Smooth Rock Cress was listed as a state Special Concern species in 2013, due to its few known locations, low populations and the threats of invasive species, primarily buckthorn and non-native honeysuckles.
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Photos by K. Chayka taken at Whitewater Wildlife Management Area, Winona County. Photos courtesy Peter M. Dziuk taken at Whitewater WMA, Winona County, and Zumbro Falls, Wabasha County.
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