Much like no. 1 [Utricularia cornuta Michx.]; flowering branches greenish-purple to purple; nodes mostly 4-32; bractlets slenderly subulate; fls smaller, some of them cleistogamous; palate without spreading margin, or with only a very narrow one. Wet shores of bogs and ponds on or near the coastal plain; s. N.Y. to Fla. and Miss. Plants blooming in summer have the spur 6-8 mm and the lower lip 8-12 (avg. 9) mm. (Stomoisia j.) Plants blooming in fall are smaller, with much smaller fls, the spur only 2-3 mm. (U. virgulata; Stomoisia v.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.