Annuals, 4-42 cm. taprooted. Stems erect or ascending, branched, eglandular or stipitate-glandular, especially distally. Leaves basal and cauline; petiolate (at least basal); blades broadly to narrowly oblanceolate, 2-15 cm, margins entire or remotely toothed or lobed, lobes acute or rounded, apices acute to obtuse, faces glabrous or lightly glandular-villous; cauline appearing unequal and opposite proximal to distal peduncles, petiolate or sessile, blades oblanceolate to linear, gradually reduced, bases ± clasping, margins entire or dentate. Heads borne singly. Peduncles from branching, leafy stems. Involucres 2-8 mm. Phyllaries 5-10, erect in fruit, narrowly to broadly lanceolate, midveins evident, not prominent or keeled, apices acute. Florets 12-35; corollas yellow, 2-11 mm (barely equaling to much surpassing phyllaries). Cypselae fusiform, 1.4-1.7 mm, broadest at or ± beyond middles (apical areas ± equal to basal areoles), 15-ribbed; pappi 0. 2n = 8.

The name Krigia oppositifolia Rafinesque, long in use for this species, was not accepted by Rafinesque in his original publication and is therefore invalid.

This species was found in flower on May 12, 1935, by Scott McCoy. It was growing in wet soil on the border of a woods along State Road 62 a few miles east of Boonville, Warrick County.

Slender, branching, usually several-stemmed annual 5-45 cm; lvs basal and cauline, linear-oblong to oblanceolate or a little broader, entire to pinnatifid, 1.5-15 cm נ2-20 mm; some of the upper internodes commonly shortened so that the lvs appear opposite, with several long, sometimes similarly branched and bracteate peduncles in their common axil; heads 8-15 mm wide in fl, yellow with a golden center; invol 3-5 mm high, its bracts 6-10, lanceolate or broader, persistently erect, becoming keeled in fr; pappus wanting, or a mere scaly vestige; 2n=8. Generally in moist, low places; s. Va. to Fla., w. to s. Ill., se. Neb., Kans. and Tex. Apr.-July. (Serinia o.)

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.