Annuals, (1-)2-10(-30+) cm (taprooted, often stoloniferous and/or mat-forming). Stems 1-5+, ± procumbent to erect, simple or branched, glabrous or strigillose to villous [piloso-hispid] (hairs mostly basifixed). Leaves basal or basal and cauline; alternate; sessile or petiolate (bases ± clasping); blades ± obovate to spatulate, usually (1-)2-3-pinnately or -pinnati-palmately lobed (ultimate lobes oblong or lanceolate to oblanceolate or spatulate), ultimate margins entire or dentate, faces glabrous or strigillose to villous. Heads disciform, borne singly (sessile in leaf axils). Involucres ± hemispheric or broader, 2-8+ mm diam. Phyllaries persistent, 5-8+ in 1-2+ series, distinct, lanceolate to ovate, subequal, margins and apices (usually colorless, sometimes brownish) scarious. Receptacles flat to hemispheric or conic, epaleate. Ray florets 0 (peripheral, pistillate florets 5-100+ in 1-8+ series; corollas 0, styles sheathed by pericarp tissues, soon indurate, becoming spinelike). Disc florets 2-8+, functionally staminate; corollas yellowish or whitish, tubes ± cylindric, throats campanulate to funnelform, lobes (2-)4, ± deltate (without resin sacs). Cypselae: (bodies) ± obovate to oblanceolate or oblong-cuneate, ob-compressed or -flattened, winged (wings entire or sculpted), faces glabrous or ± scabrellous to hirtellous or (distally) villous to pilose or arachnose, glabrescent (pericarps without myxogenic cells or resin sacs); pappi 0 (persistent stylar sheaths indurate, spinelike). x = unknown.