Pittonia 3: 97. 1896
Annuals or, rarely, perennials; (short-lived, terrestrial or of wet habitat, not submerged); glabrous or hirsute, (trichomes cylindrical). Stems (few to several from base), usually ascending, decumbent, or prostrate, rarely erect, branched distally, 1–4.2(–5) dm, (hirsute proximally). Basal leaves not rosulate; blade margins pinnatifid. Cauline leaves shortly petiolate or sessile; blade oblong or oblanceolate to obovate, (terminal lobe oblong), (2–)3.5–10(–12) cm × (5–)10–30(–37) mm, (lateral lobe smaller than terminal), base usually auriculate, rarely amplexicaul, margins: proximal pinnatifid or sinuate, distal dentate or entire, (surfaces sparsely pubescent). Racemes elongated. Fruiting pedicels divaricate-ascending to horizontal, straight or recurved, (1.2–)1.7–5(–8) mm. Flowers: sepals erect, oblong, 0.8–1.8 × 0.5–1 mm; petals (erect), yellow, oblanceolate to spatulate, 0.5–1.8 × 0.2–1 mm; median filaments 0.9–1.3mm; anthers ovate, 0.3–0.5 mm. Fruits silicles or siliques, curved, ovoid to pyriform, 2–8(–8.8) × (0.5–)1–2.5 mm; valves glabrous; ovules (20–)30–80 per ovary; style 0.3–1 mm. Seeds biseriate, brown, cordiform, 0.5–0.7 mm, colliculate. 2n = 16.
Phenology: Flowering May–Sep.
Habitat: Muddy shores of lakes and ponds, stream beds and banks, edges of cultivated fields, wet roadside, meadows, seepage areas, ditches, creeks, gravel bars
Elevation: 100-3500 m
Alta., B.C., Sask., Ariz., Ark., Calif., Colo., Idaho, Ill., Kans., Mich., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Oreg., S.Dak., Tex., Utah, Wash., Wyo., Mexico (Coahuila).