Cerastium glomeratum Thuill., Sticky Mouse-ear

Account Summary

Growth form and preferred habitats

This rather scruffy, slightly sticky, often dust-coated, weedy winter or summer annual is a stress-tolerant ruderal that rarely grows anywhere except on disturbed ground (Grime et al. 1988). The plant has erect or ascending, flexuous and fragile stems up to about 30 cm in height. The stems have long, non-glandular hairs below and glandular hairs above. Leaves in the mid-stem are elliptic, 1.3-2.1 times as long as wide and hairy all over. Stickiness also resides in the compact inflorescence of the plant which is densely covered with glandular hairs (Garrard & Streeter 1983).

Common and widespread in lowland areas of both Britain & Ireland, C. glomeratum prefers moderately fertile or manure-enriched conditions, but it will tolerate a range from moist to dry, light sandy to clayey soils in sunny to shaded situations. Sticky Mouse-ear is often found in bare areas of compacted clayey soil where surface water lies in winter. It is also frequent around gates where animal stale and trample the ground, and at the shady base of damp walls in both urban areas and farmyards.

C. glomeratum sometimes thrives in thinly-grassed patches in lawns and in regularly mown or trampled grasslands, tracks or soil surfaces, as well as in more open, moderately disturbed waste ground. Previously, before the near extinction of arable agriculture in Fermanagh, it would have been an abundant field weed. It cannot, however, survive regular cultivation in gardens. Likewise, in well managed grassland, it is only a poor competitor with perennial grasses and sooner or later it becomes scarce, rare or almost entirely absent from such situations (Sinker et al. 1985).

Fermanagh occurrence

In Fermanagh, C. glomeratum has been commonly recorded in 287 tetrads, 54.4% of those in the VC.

British and Irish occurrence

Widespread and common throughout lowland Britain & Ireland, it is however scarce in wet, boggy ground in parts of W Ireland and NW Scotland since the species favours or requires moderately fertile soil conditions (Preston et al. 2002)

Flowering reproduction

As with C. fontanum (Common Mouse-ear) and Stellaria media (Common Chickweed), germination can occur throughout the year given mild conditions, although there are strong peaks in the early spring and autumn. Frost-tolerant overwintering juvenile plants have five to seven small, tightly clustered leaves, but do not develop a real rosette (Salisbury 1962; Jonsell et al. 2001). The small flowers appear in compact cymose clusters from April to September or later, even until the occurrence of the first autumn frost. The flowers are little visited by insects but are self-compatible and will automatically self-fertilise. In some populations, flowers are frequently produced without petals and are pollinated and fertilised while still in bud (ie they are cleistogamous, a term literally meaning 'closed marriage') (Clapham et al. 1987).

Fruiting plants have a much more lax inflorescence due to elongation of the internodes after fertilisation, and each 6-10 mm curved, cylindrical capsule contains around 50 seeds (Salisbury 1964).

Seed dispersal

The capsule apex splits to form ten teeth and releases the small, light, tuberculate, yellow-brown seed on the breeze. In common with many other species in the family, the seeds are long-persistent (Thompson et al. 1997). Apart from wind dispersal, transport of the species is very closely associated with man and his activities. For instance, Sticky Mouse-ear is such a very common weed in horticultural nurseries and garden centres, customers must often be transporting it home with potted or containerised plants.

Fossil record

None found. Exactly what should be taken from this negative result is not clear, although the link with man and environmental disturbance due to agriculture and stock animals is obvious. Seeds of other common related species do occur in the fossil record, but sometimes in only a small number of sites, eg C. fontanum and C. cerastoides (L.) Britton (Starwort mouse-ear) (Godwin 1975, pp. 147-8).

European and world occurrence

C. glomeratum has been spread by man from W Europe and the Mediterranean to India, N & S America, S Africa, S Australia and New Zealand, and become circumpolar (Hultén & Fries 1986, Map 750). In Norway, C. glomeratum is recognised as being a neophyte introduction imported with ballast (Jonsell et al. 2001).

Names

The genus name 'Cerastium' is from the Greek 'keras' or 'kĕrastēs' meaning a horn or horned respectively, from the fact that some species have curved seed capsules resembling horns as they emerge from the calyx (Johnson & Smith 1946; Stearn 1992). The Latin specific epithet 'glomeratum' is derived from 'glomus', a ball of yarn and means 'aggregated' or 'gathered into a round mass', clearly referring to the compact, cymose, cluster of the inflorescence (Gilbert-Carter 1964; Gledhill 1985). The English common name 'Sticky Mouse-ear' is a recent book name of no folklore significance.

Threats

None.

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