Key to Wisconsin Alismataceae

Author: Christopher D. Tyrrell

• 1a. Carpels ≤ 28, in one ring-like whorl; receptacle flattened, disk-like; inflorescence paniculate with numerous rebranching branches Alisma

• 1b. Carpels >28, usually very numerous; receptacle convex, dome-shaped; carpels in several spirally arranged whorls; inflorescence verticillate, usually branching or rebranching in whorls of three or more 2

• 2a. Achenes laterally flattened, winged and smooth, without ribs; bracts without bracteoles at the base of inflorescence branch whorls; roots septate Sagittaria

• 2b. Achenes terete, ribbed but not winged; bracts and bracteoles at the base of inflorescence branch whorls; roots not septate Echinodorus