Mouse-ears
What are they?
Members of the campion family, mouse-ears are a group of small to very small, mostly annual (but some perennial) plants with five-petalled, white flowers. In most species, the petals are deeply notched or cleft at the tip and all have very obviously hairy leaves - a feature that gives them their English name.
Where are they found?
Most species are plants of open ground, growing either as annuals on bare or disturbed ground, or as perennials in grassy places.
Identification
In the annual species, identification can be difficult as the plants are often very small, regularly consisting of just three or four leaves and a single flower! Critical for identification is the appearance of tiny, leaf-like bracts, that can be found at the base of the flowers In particular, the presence or absence of a thin, membrane-like section at the edge/tip of these bracts is important.
Sticky Mouse-ear Cerastium glomeratum
Native. A common and often locally abundant species of disturbed and waste ground, especially as a weed of cultivation and in urban areas. Flowers mostly April to September but occasionally also other times, especially in urban areas. A small species, but typically larger and with broader leaves than the other annual species. Flower bracts all green, with no membranous margin; flowerheads rather dense.
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Little Mouse-ear Cerastium semidecandrum
Native. Widespread on sandy, calcareous soils, being most common in Breckland and sandy coastal areas. Flowers late March to June. A small to very small, annual species. Flower bracts with very broad and obvious, membranous margin; flowerheads at first dense, becoming more open with age; flowers with only five stamens (other mouse-ears have 10). Petals narrow and noticeably shorter than sepals.
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Sea Mouse-ear Cerastium diffusum
Native. Widespread on sandy soils or established coastal shingle habitats but nowhere common and almost always hard to find among larger numbers of Little Mouse-ear. Flowers April to June. A small to very small, annual species. Flower bracts all green, with no membranous margin; petals broader and longer than those of Little Mouse-ear.
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Dwarf Mouse-ear Cerastium pumilum
Native in the western half of the UK but has only occurred recently in East Anglia as a rare casual, mostly in Cambridgeshire. Flowers April to June. A small to very small, annual species. Flower bracts with a relatively narrow membranous margin, intermediate between Little and Sea Mouse-ears. Petals at least as long as sepals.
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Common Mouse-ear Cerastium fontanum
Native and common throughout the region in a wide range of habitats but especially grassy places and on old walls. Flowers mostly April to June. A low growing perennial species that forms spreading mats of dark green foliage, that helps to distinguish it from the annual species that only form simple rosettes of leaves, terminating in a flowering stem. Leaves a little longer and more pointed at the tip than those of the annual species. Most plants are of the subspecies vulgare but subspecies holosteoides also occurs and differs by being more or less hairless.
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Field Mouse-ear Cerastium arvense
Native. Widespread but only common in grassland on light, sandy soil over chalk and perhaps more common in East Anglia's Breckland than anywhere else in Britain. Flowers mostly April to June with a few into late summer. A low growing perennial species with flowers that are much larger and more showy than other mouse-ears. Leaves lanceolate, thickly hairy.
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Snow-in-summer Cerastium tomentosum
Introduced from southern Italy and now widespread as an escape from cultivation. Most often found in urban environments along roadsides, grassy banks, walls, cemeteries and similar places. Flowers mostly April to June with a few into late summer. A perennial species that forms low mounds of silver-grey, densely hairy leaves.
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Hybrid Mouse-ear Cerastium x maueri
Has occurred spontaneously in a handful of places as a hybrid between the native Field Mouse-ear and the introduced Snow-in-summer. In appareance it is intermediate between the two parents.
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Hybrid Mouse-ear, Snow-in-summer |
Hybrid Mouse-ear, Snow-in-summer |