Ammannia auriculata Willd.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Erect, 1–3 dm, pyramidally branched, with short ascending branches beginning above the base; lvs membranous, linear or lance-linear, 1.5–5 cm, cuneate to a barely auriculate sessile base; cymes 3–15-fld, on slender axillary peduncles 4–10 mm; pedicels 1–3 mm; fls small, the hypanthium at an thesis mostly 1.5–2.5 mm, the caducous pet mostly 1–2 mm, deep rose-purple; anthers 4, yellow; sep triangular, shortly surpassed by the fr, this 2–3.5 mm thick; style persistent, 1.5–3 mm; ovary and fruit 4-locular; 2n=32. Borders of ponds, and similar wet places; N.D. to Tex., and irregularly pantropical, perhaps not entering our range, most of our plants so identified in the past being extremes of no. 2. [Ammannia coccinea Rottb.] July–Oct.