Onosmodium molle (False Gromwell)
|Also known as:||Soft-hair Marbleseed|
|Habitat:||part shade, shade; dry sandy or rocky soil; prairies|
|Bloom season:||June - July|
|Plant height:||1 to 4 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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A 1-sided raceme to 6 inches long of nodding, short-stalked tubular flowers. Flowers are white or tinged yellow or green, ½ to ¾ inch long, covered in short hairs, with 5 triangular lobes at the tip that close the mouth of the tube. A long white style projects from the tube like a large stinger; the style remains long after the petals wilt away. The calyx holding the flower has 5 narrow lobes; depending on the variety are about half as long as the floral tube or as long as the tube.
Leaves and stems:
Leaves are 2 to 4 inches long, ½ to 1½ inches wide, lance to narrowly egg-shaped, toothless and stalkless, with several deep veins, alternately attached, reduced to bracts in the upper plant. Leaves are bristly hairy, depending on the variety densely covered in appressed hairs, or less densely covered with more spreading hairs. Stems are covered in bristly hairs. Multiple stems arise from a woody root, often branching in the upper plant.
Fruit is a smooth nutlet that ripens from green to brown to white, somewhat conical to egg-shaped. The nutlet may dull and constricted just above the base forming a collar, or shiny and without a collar.
False Gromwell goes by several Latin names, including Onosmodium bejariense and Lithospermum occidentale, but the accepted name in Minnesota is Onosmodium molle. There are 2 varieties in Minnesota: var. hispidissimum can reach heights up to 4 feet, is quite coarsely and conspicuously hairy, has the long calyx lobes and the dull, collared nutlets; var. occidentale, the more common, is a smaller plant, more loosely hairy, and has the short calyx lobes and shiny, uncollared nutlets. A third variety not found in Minnesota, var. molle, is a more southern species with pitted nutlets.
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Photos by K. Chayka taken in Lac Qui Parle WMA. Photos courtesy Peter M. Dziuk taken in Lac Qui Parle and Dakota counties.
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