Amphidiploid of nos. 1 [Ammannia auriculata Willd.] and 3 [Ammannia robusta Heer & Regel]; stems often freely branched; cymes mostly with 3 or more fls, subsessile or on a short stout peduncle to 4+ mm; pedicels short and stout, or none; hypanthium mostly 2-3.5 mm; pet 1.7-2.5+ mm, deep rose-purple; anthers deep yellow; fr 3.5-4.5 mm thick; 2n=66. N.J. and Pa. to N.D., s. to trop. Amer.; Calif. July-Sept.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.

From Flora of Indiana (1940) by Charles C. Deam

Muddy borders of sloughs, ponds, bayous, reservoirs, and streams and in dredged ditches. Local but often abundant where found.

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Indiana Coefficient of Conservatism: C = 2

Wetland Indicator Status: OBL

Diagnostic Traits: Annual with opposite leaves; flowers 2-5 per axillary cluster, borne on peducles 0-4.5 mm long; flowers usually 4-merous, purplish.