13. Cerastium dubium (Bastard) Guépin, Fl. Maine et Loire, ed. 2. 1: 267. 1838.
Anomalous mouse-ear chickweed
Stellaria dubia Bastard, Suppl. Fl. Maine-et-Loire, 24. 1812; Cerastium anomalum Waldstein & Kitaibel; Dichodon viscidum (M. Bieberstein) Holub
Plants annual, taprooted. Stems erect, many-branched from base, 10-40 cm, minutely viscid-glandular; small axillary tufts of leaves usually absent. Leaves not marcescent, distal sessile, proximal spatulate; blade linear or linear- lanceolate to linear-oblong, 10-30 × 1-4 mm, apex obtuse to subacute, glabrous or sparsely and minutely viscid-glandular. Inflorescences lax, 3-21(-30)-flowered cymes; bracts narrowly lanceolate, glandular-pubescent. Pedicels erect, slender, 2-15 mm, 0.5-3 times as long as sepals, glandular-puberulent Flowers: sepals ovate-lanceolate, 5-6 mm, margins narrow, apex acute to obtuse, minutely viscid-glandular; petals oblanceolate, 5-8 mm, 1.5 times as long as sepals, apex 2-fid; stamens 10; styles 3(-4). Capsules oblong-ovoid, straight, 8-11 mm, ca. 2 times as long as sepals; teeth 6, occasionally 8, erect to spreading, margins convolute. Seeds pale brown, ovate, 0.6 mm diam., tuberculate; testa not inflated. 2n = 36, 38.
Flowering spring. Alien weed of cultivated land; 200-800 m; introduced; Ark., Idaho, Ill., Ind., Kans., Ky., Miss., Ohio, Oreg., Tenn., Va., Wash.; s Europe; Asia.
First collected in North America in 1966 in Washington, Cerastium dubium has now been gathered from many widely scattered sites, and appears to be spreading rapidly.
Shildneck, P. and A. G. Jones. 1986. Cerastium dubium (Caryophyllaceae) new for the eastern half of North America (a comparison with sympatric Cerastium species, including cytological data). Castanea 51: 49-55.