Thought it was probably D. intermedia in the field, but upon closer inspection: hairy petioles, leaf shape more "paddle" shaped than intermedia (in my opinion), within ~2 feet of both parents, and just this one individual seen. Flowers were present, but did not check for presence/absence of fruit. D. anglica not known from this site, and did not see D. intermedia anywhere in this area.
suspected F1 - D. linearis and D. rotundifolia nearby. Second image compares D. anglica (middle blade) and the two parents. There are well established D. anglica populations inland in the MI U.P. but coastal sites usually have F1 crosses only... in my experience.
Sand area of Lake Jackson near boat ramp. low water area.