Glabrous, somewhat fleshy annual 1-10 dm from a short taproot; lvs linear, entire or nearly so, to 20 נ1 cm, entire; heads remotely solitary to usually several or many in an open infl; invol rather narrow, 5-8 mm, its usually well imbricate bracts acuminate, often somewhat greenish, but scarcely herbaceous, frequently purplish toward the margins and tips, all except sometimes the outer with scarious or hyaline margins; rays inconspicuous, bluish, more numerous than the 5-15 disk-fls, becoming circinately rolled outwards, longer than the style, but scarcely or not at all exceeding the copious fine white pappus; 2n=10, 20. Coastal, mostly saline marshes; N.B. and se. Me. and N.H. to trop. Amer., and rarely and irregularly inland to e. N.Y. and s. Mich.; also in a nonmaritime, often weedy var. in the Ozark reg., n. to Nebr. Most of our plants are var. subulatus, as here described; plants of N.B. have blunter lvs, and a less imbricate, slightly more herbaceous invol, and have been distinguished as var. obtusifolius Fernald.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.