Orobanche ludoviciana (Louisiana Broomrape)
|Also known as:||Prairie Broom-rape|
|Habitat:||part shade, sun; sandy soil; prairie|
|Bloom season:||June - September|
|Plant height:||3 to 12 inches|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Numerous flowers are clustered in a dense spike, the spike often making up to 2/3 of the plant height. Flowers are tubular, ½ to ¾ inch long, the lower ones may have up to a 1-inch stalk while upper ones are stalkless. Flowers are densely hairy with color ranging from a light pink to often deep purplish rose with yellow on the inside lower lip. The typical flower has a 2-lobed upper lip and 4-lobed lower though they can be split with 3 above and 3 below. Sepals are also tubular with five long lance-linear lobes, brownish in color and densely hairy. Each flower is attended by a broad oval bract tapered to a point as well as 1 or 2 smaller bractlets, all brownish colored and densely hairy.
Leaves and stems:
Stems are usually simple or may be branched, often subterranean with many scale-like leaves.
Fruit is a 2-sectioned capsule, containing many seeds.
While spotting this small plant takes a keen eye, identifying it is relatively easy. Louisiana Broomrape has no chlorophyll and is parasitic on species of Artemisia spp. and other members of the aster family. There are over a 100 species of Orobanche identified worldwide and a number of them are very serious economic crop pests in arid regions, by starving their host plants of nutrients and moisture. Several old world species have made their way into North America and are pests of clovers, tobacco and tomatoes. Minnesota's three species are highly specialized in their host relationships, so much so that as their native ecosystems have been diminished by intensive agricultural practices, mining, development and recreational activities, all were state listed as Special Concern in 1984. According to the DNR, this species has suffered significantly from loss of its sand prairie and savanna habitat and was elevated to Threatened status in 2013.
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Photos by K. Chayka and Peter M. Dziuk taken near Jordan in Scott County.
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