Annual or perennial herb 3 - 15 cm tall Stem: free-floating, brown, to 1 m long. Leaves: borne in whorls of five to seven, each whorl branching into another whorl of very slender segments, with many segments having tiny bladders on the tips. Flowers: borne one to four on a stout emersed stalk (scape) arising from the ground. The two-lipped petals are violet or reddish violet with a yellow spot in the lower lip, the upper lip being shorter and almost as wide as the 7 - 13 mm long lower lip, and the lower lip being three lobed with the outer lobes each having a small projection. Spur (extended sac at base of petals) shorter than lower lip and pressed against it. Fruit: a two-valved capsule containing small seeds.
Similar species: Utricularia resupinata also has violet flowers, but the flowers are borne solitary on a slender stem. The plant appears leafless and is not free-floating.
Flowering: early July to late August
Habitat and ecology: Shallow water.
Occurence in the Chicago region: native
Etymology: Utricularia comes from the Latin word utriculus, meaning "a small bottle."This refers to the insect-trapping bladders on the leaves and runners of the bladderworts. Purpurea means purple.
Author: The Morton Arboretum
From Flora of Indiana (1940) by Charles C. Deam
Local and sometimes common. In 1930, in a bayou of about 5-10 acres in Lake Cicott, Cass County, it was common in about 3-5 feet of water, associated with Utricularia macrorhiza, Nuphar advena, and Nymphaea tuberose. It has been reported also from Marshall County.
Stems submersed, to 1 m; lvs in whorls of 5-7, verticillately branched into filiform segments, many of which bear a terminal bladder; flowering branches 3-15 cm, 1-4- fld; cor 1 cm, violet or red-violet, the lower lip with a basal yellow spot, 3-lobed, the lateral lobes strongly and separately elevated at base into a palate; spur shorter than and appressed to the lower lip. Quiet water; Que. and N.S. to Minn. and n. Ind., s. along the coastal plain to Fla. and La.; W.I. July-Sept. (Vesiculina p.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.