Annuals, 5-60 cm (self-incompatible). Stems erect. Leaves mostly cauline; proximal opposite (often crowded), distal alternate; sessile; blades spatulate to linear, margins entire or toothed, faces hirsute to strigose (distal leaves sometimes stipitate-glandular as well). Heads radiate, in ± umbelliform arrays. Peduncular bracts: pit-glands, tack-glands, and/or spines 0. Involucres ± obconic or urceolate to globose, 3-5 mm diam. Phyllaries 2-12 in 1 series (lanceolate to lance-attenuate, herbaceous, each usually wholly enveloping a ray ovary, abaxially hirsute, hair tips ± uncinate). Receptacles flat to convex, glabrous or setulose, paleate (paleae falling, in 1 series between rays and discs, connate, herbaceous to ± scarious). Ray florets 2-12, pistillate, fertile; corollas yellow, sometimes purple-veined abaxially. Disc florets 1-65, functionally staminate; corollas yellow, tubes shorter than funnelform throats, lobes 5, deltate (anthers ± dark purple; styles glabrous proximal to branches). Ray cypselae compressed, clavate, arcuate, basal attachments oblique, faces glabrous, apices beaked. Ray pappi crowns of scales (0.1-1 mm); disc pappi of 5-7 (white or purple-tipped) subulate, crisped, ciliolate scales (2.5-3 mm). x = 8.

Recognition of Jensia is based on evidence that Madia in the sense of D. D. Keck (1959) is not monophyletic; the epappose annuals constituting Madia in the restricted sense are more closely related to Carlquistia than to Jensia (B. G. Baldwin 1996).