Plants annual, with slender taproots. Stems erect or ascending, branched, 5-45 cm, hairy, glandular at least distally, rarely eglandular; small axillary tufts of leaves absent. Leaves not marcescent, ± sessile; blade 5-20(-30) × 2-8(-15) mm, apex apiculate, covered with spreading, white, long hairs; basal with blade oblanceolate or obovate, narrowed proximally, sometimes spatulate; cauline with blade broadly ovate or elliptic-ovate. Inflorescences 3-50-flowered, aggregated into dense, cymose clusters or in more-open dichasia; bracts: proximal herbaceous, distal lanceolate, apex acute, with long, mainly eglandular hairs. Pedicels erect to spreading, often arcuate distally, 0.1-5 mm, shorter than capsule, glandular-pubescent. Flowers: sepals green, rarely dark-red tipped, lanceolate, 4-5 mm, margins narrow, apex very acute, usually with glandular hairs as well as long white hairs usually extending beyond apex; petals oblanceolate, 3-5 mm, rarely absent, usually shorter than sepals, apex deeply 2-fid; stamens 10; styles 5. Capsules narrowly cylindric, curved, 7-10 mm; teeth 10, erect, margins convolute. Seeds pale brown, 0.5-0.6 mm, finely tuberculate; testa inflated or not. 2n = 72. Flowering throughout growing season. Arable land, waste places, roadsides; 0-1800 m; introduced; B.C., Nfld. and Labr. (Nfld.), N.S., Ont., Que., Yukon; Ala., Alaska, Ariz., Ark., Calif., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Kans., Ky., La., Md., Mass., Mich., Miss., Mo., Mont., Nev., N.J., N.Mex., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., Tenn., Tex., Va., Wash., W.Va.; Europe; introduced and common in Mexico. Cerastium glomeratum often has been reported as C. viscosum Linneaus, an ambiguous name; see discussion under the genus.