1a. Polanisia dodecandra (Linnaeus) de Candolle subsp. dodecandra
Polanisia graveolens Rafinesque
Leaflets: blade apex acute to obtuse. Inflorescence bracts lanceolate to ovate. Petals white (sometimes pinkish), (3-)5-7 (-8) mm. Stamens (6-)7-10 (-14) mm, ± equaling or slightly longer than petals. Seeds roughened. 2n = 20.
Flowering summer-early fall. Roadsides, riverbanks, gravel bars, flood-scoured shorelines, grasslands, disturbed sites; 0-1100 m; Ont., Que.; Ala., Ariz., Ark., Calif., Colo., Conn., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., S.Dak., Tex., Vt., Va., W.Va., Wis., Wyo.
Subspecies dodecandra is smaller-flowered than the other subspecies and is most often found in northeastern and midwestern states. ‘White Spider’ is a cultivar sometimes offered in seed catalogues. Occurrences in New England (except Vermont) probably represent adventives from farther west; this plant is common along weedy roadsides.