Utricularia cornuta (Horned Bladderwort)
|Also known as:||Spurred Bladderwort|
|Habitat:||part shade, sun; bogs, swamps, along shores|
|Bloom season:||July - August|
|Plant height:||2 to 12 inches|
|Wetland Indicator Status:||GP: OBL MW: OBL NCNE: OBL|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Raceme of 1 to 6 bright yellow ½ to ¾-inch snapdragon-like blooms at the top of a mostly naked stem. The lower lip is somewhat helmet-shaped and is sometimes shorter than the fanning upper lip, though broader. Two small sharply pointed oval bracts, larger one above and smaller below, along with two scale-like bracts on each side. A downward curving spur is below. Each flower has a short green stalk.
Leaves and stem:
Leaves are mostly hidden, integrated within the surface of the mucky soil. Occasionally, leaves are absent. When present, they are unbranched, linear (like a slender blade of grass), bear bladders, and alternate along the stem. Root-like branches are generally present. Flowering stems are green or yellow-green, with a few widely spaced, alternately attached, scale-like leaves, each not more than 1/12 inch long.
Fruit is a tiny capsule.
Another one of Minnesota's carnivorous plant species, Horned Bladderwort is not as widespread as the Common Bladderwort (Utricularia vulgaris). It is highly restricted to specific open bog habitats that are exceedingly harder to find in Minnesota. While this species’ range extends to eastern Texas it is more limited to northern Minnesota, more likely due to habitat requirements than cold temperatures. The population in Anoka County is a rather disjunct population within Minnesota, but again it is in a rare habitat environment in which it can thrive. There are 8 bladderwort species in Minnesota, most with yellow flowers and similar leaves. Distinguishing features are the size and shape of the spur, the general shape of the flowers, including relative sizes of the upper and lower lips, the bladder size and location, and leaf arrangement. Horned Bladderwort bladders are unseen, the spur is fairly slender and mostly points down, the lower flower lip may be shorter than the upper, though broader, the flowers are solid yellow without red venation, and the leaves are unbranched. When not in bloom, it is very difficult to distinguish from Lavender Bladderwort (Utricularia resupinata), which has very similar leaves and violet flowers. Although the commonly held view is that the bladders of bladderworts are for capturing and digesting microorganisms that provide the plant with nutrients, bladders more often have been observed to contain communities of microorganisms (bacteria, algae, and diatoms) living in the bladders, not as prey, suggesting that the bladders may also, and perhaps more importantly, serve to establish mutually beneficial relationships with some microorganisms.
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Photos courtesy Peter M. Dziuk taken in Blaine, Anoka County. Photos courtesy John Thayer taken in Itasca County.
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