Field Chickweed, Field Mouse Ear: Cerastium arvense ssp. strictum (Synonym: Cerastium arvense ssp. maximum) - Perennial. Flowers large and showy, usually with petals at least 1.5 times longer than the sepals. Inflorescence open.
Doubtful Chickweed: Cerastium dubium - Weedy annual. Flowers small with petals longer than the sepals. 3 styles present. Inflorescence open.
Big Chickweed, Common Mouse Ear, Common Mouse-ear Chickweed, Mouse-ear Chickweed: Cerastium fontanum ssp. vulgare (Synonyms: Cerastium holosteoides, Cerastium vulgatum) - Weedy biennial to perennial. Matted growth. Flowers small with petals about equal to the sepals. Flowers not in tight clusters.
Sticky Cerastium, Sticky Chickweed: Cerastium glomeratum (Synonyms: Cerastium glomeratum var. apetalum, Cerastium glomeratum var. glomeratum, Cerastium viscosum, Cerastium viscosum var. viscosum) - Weedy annual. Sepals 4-5 mm long. Flowers small with petals roughly equal to the sepals in length. Flowers in tight clusters.
Nodding Chickweed, Nodding Mouse Ear: Cerastium nutans (Synonyms: Cerastium brachypodum, Cerastium nutans var. nutans) - Weedy annual. Flowers small with petals slightly shorter than to equal to the sepals. Plants ascending to erect. Pedicels and calyx with glandular hairs. Inflorescnece not in tight clusters of flowers.
Sticky Mouse Ear Chickweed: Cerastium pumilum (Synonyms: Cerastium glutinosum, Cerastium pumilum) -
Fivestamen Chickweed, Little Mouse Ear: Cerastium semidecandrum - Weedy annual. Flowers small with petals about 1 mm shorter than the sepals. Sepals with wide, white-membranous margins. Inflorescence not with flowers in tight clusters.