Cerastium brachypetalum Desf. ex Pers.

This winter annual germinates in October/ November and flowers in April and May. The flowers self-pollinate, and seed is set after May (1). It seems that this species has particularly poor dispersal abilities, as plants appear repeatedly in the same place as in previous years (1). The seeds require open ground in which to germinate and grow; this plant cannot compete with dense grass or vegetation (4).

Grey mouse-ear is one of the species targeted by Plantlife's 'Back From the Brink' campaign. Controlled burning, used as a conservation management tool at the Bedfordshire site has had promising results (1).

This endangered plant was first discovered in Great Britain in 1947 (1). It is pale green to grey in colour and is covered in fairly long, downy hairs. The small leaves grow in pairs that are positioned oppositely on the stem. The flowers are small and white; the specific name brachypetalum derives from the Greek brakhys, meaning short and petalum which means petal (2).

Inhabits open habitats on old calcareous grassland, as well as railway banks and cuttings (1). The soils are often shallow and suffer from droughts in the summer, which keeps competing vegetation in check (4). In Bedfordshire the plant typically grows on anthills on two railway banks that face to the west (1). In Europe it occurs on walls, rocky limestone outcrops and ledges (4).

In the UK, this species is known from Bedfordshire and at 6 sites in west Kent (1). It also occurs in western, southern and central Europe and in France on the Channel coast (1).

Classified as Endangered in Great Britain (1).

One of the six UK sites for this species was destroyed during construction of the Channel Tunnel Rail Link. Seeds and soil from this site were transferred to a new site and are growing well (4).

The wholly herbaceous bracts of Cerastium brachypetalum distinguish it from C. fontanum subsp. vulgare, C. semidecandrum, and C. pumilum; the ciliate petal and filament bases distinguish it from C. diffusum and C. glomeratum. Cerastium brachypetalum differs from all those species in the long, silvery hairs that give it a grayish appearance. In Europe C. brachypetalum is more variable and eight subspecies have been recognized, two of which—subsp. brachypetalum and subsp. tauricum—occur in North America. However, they differ only in the absence or presence of glandular hairs, an insufficient distinction for recognition at the subspecific level.

Plants annual. Stems erect, simple or branched at base, 5.5-30 cm, shaggy, hairs silvery, spreading-ascending; small axillary tufts of leaves absent. Leaves not marces-cent; blade 4-15(-20) × 1.5-5(-7) mm, pubescence of long, glandular and/or eglandular hairs; basal ± crowded, blade oblanceolate, spatulate, apex obtuse; cauline sessile, blade lanceolate or elliptic, apex acute. Inflorescences lax, dichasiate, 3-30-flowered cymes; bracts herbaceous, lanceolate, densely pubescent, with long, ascending, glandular or eglandular hairs. Pedicels erect or ascending, bent distally in fruit, 6-15 mm, longer than capsule, shaggy, glandular or eglandular. Flowers: sepals lanceolate, 4-4.5 mm, foliaceous, with or without narrow margins, densely pubescent, hairs exceeding sepal tips; petals oblanceolate, 2-3 mm, ca. 0.5 times as long as sepals, apex 2-fid, sparsely ciliate proximally; stamens 10, with few long hairs near filament base; styles 5. Capsules cylindric, slightly curved near apex, 5-7 mm, ca. 1.5 times as long as sepals; teeth 10, erect, margins convolute. Seeds pale brown, 0.5 mm diam., acutely tuberculate; testa not inflated. 2n = 72 (Europe), 88, 90.

introduced; Ala., Ark., Fla., Ga., Idaho, Ill., Ind., Kans., Ky., Miss., Mo., N.Y., N.C., Ohio, Okla., Oreg., Pa., S.C., Tenn., Tex., Va., W.Va.; Eurasia.

Flowering spring.

Dry, sandy places, roadsides, arable land, disturbed, open areas; 0-400m.

Cerastium brachypetalum subsp. tauricum (Sprengel) Murbeck; C. tauricum Sprengel

Cerastium brachypetalum, commonly called gray chickweed, grey mouse-ear or gray mouse-ear chickweed, is a spring blooming annual plant species. It is native from Eurasia and introduced and naturalized in North America.

Cerastium brachypetalum is one of 101 species deemed high priorities for conservation in the UK by the wild flower and plant charity Plantlife.