Bladderwort (Utricularia spp.)
Updated: May 15
Bladderwort is one of the most common aquatic plants in Conway Lake and is easily identified by the small bladders (2-4 mm in diameter) on its branched leaves. The plant is typically loosely anchored to the bottom and can grow to heights of 2-3 feet. You may also see it detached as free-floating mats.
Several different species of bladderwort have been identified in Conway Lake: whorled bladderwort (Utricularia purpurea), common bladderwort (Utricularia vulgaris), and flat-leaf bladderwort (Utricularia intermedia) (see photos below). The most common of these is whorled bladderwort and it occurs in all sectors of Conway Lake. The other two have been identified in South Cove by Maria Gross.
Interesting fact: bladderwort is a carnivorous plant feeding on small insects, larvae and other planktonic organisms. The bladders are not little floats – they are for capturing prey. There are trigger hairs on each bladder that open a trap-door and suck in water along with the organism that triggered the reaction. Once inside the bladders, the organism is digested by enzymes, then special cells take the digested material and move it to the stem. See photo at bottom of page.
Look Alikes: Bladderwort may resemble the milfoils, but there are two key distinguishing features. One is the bladders on the leaves for which the plant is named. The other is that milfoils have feather-like leaves that have one central leaf stem with nearly opposite unbranched leaflets. The leaflets of bladderwort are more of a branching-forking configuration.
Common bladderwort (Utricularia vulgaris) on the left, and flat-leaf bladderwort (Utricularia intermedia) on the right. Common bladderwort has coarse, alternately arranged branch-divided leaves whereas flat-leaf bladderworts have slender stems with numerous, crowded, finely dissected leaves. Collected in South Cove by Maria Gross.
Whorled bladderwort (Utricularia purpurea) - photographed in Dolloff Cove by Don Yurewicz
Whorled bladderwort (Utricularia purpurea) - photographed in Turtle Cove by Don Yurewicz
Microscopic view of the bladders on a bladderwort. (http://www.lakestewardsofmaine.org/mciap/herbarium/Bladderworts.php)