Stellaria alsine Grimm (S. uliginosa Murray), Bog Stitchwort

Account Summary

Growth form and preferred habitats

This slender, delicate, brittle-stemmed, rhizomatous, shallow-rooted, wintergreen perennial forms low-growing mats on wet, open, sometimes disturbed fertile ground of acid to neutral reaction beside streams, ditches, marshy ground on lakeshores and in flushes by springs in grasslands. Generally, it is a good indicator of moving groundwater. Its creeping clonal mats are often hidden underneath taller vegetation, although it can sometimes grow upright and ascend to 40 cm (Stace 2010). S. alsine also colonises bare mud in other more frequently disturbed, fairly ruderal, muddy situations, eg around field gates and along wet tracks and rides in woods, where it commonly associates with Juncus articulatus (Jointed Rush), J. bufonius (Toad Rush) and Montia fontana (Blinks).

Fermanagh occurrence

In Fermanagh, S. alsine is common, with a wide variety of suitable habitat available, so that it has been recorded in 333 tetrads, 63.1% of those in the VC. In somewhat shaded, strongly eutrophic, peaty, tall fen situations, eg in reed-beds around Upper Lough Erne, it can behave as an emergent on bare mud. Otherwise, in shallow, still or very slow-flowing water it can become a floating semi-aquatic. Bog Stitchwort also occurs in more acid, infertile ground on the slopes of Cuilcagh, the highest mountain, and in mixed upland oakwood at the Correl Glen NR, plus in mixed ashwoods below the limestone cliffs of Knockmore and the sandstone ones of Poulaphouca, overlooking Lower Lough Erne. It is rare, but not unknown or excluded from the limestone areas of the county.

Reproduction, competition and survival

The small flowers are borne on the upper branches of the plant in lax, few-flowered dichasial cymes. The petals are bifid almost to the base and are shorter than the sepals, or sometimes absent. The flowers attract few insect visitors and therefore are mostly self-pollinated. Seeds are rugose-tuberculate, pale reddish brown to dark brown. Seed setting is usually sparse, but production in unshaded sites can be prolific. A large, long-persistent population can develop in the soil seed bank and some may germinate after habitat disturbance (Grime et al. 1988; Thompson et al. 1997; Jonsell et al. 2001). Capsules and seeds float, and together with fragments of the brittle stems broken by disturbance, they enable water or mud-borne dispersal and colonisation of suitable moist habitats. This process is often assisted by man and his stock animals. S. alsine is a weak competitor and is favoured by disturbance of the soil surface that allows seed germination. Populations are often ephemeral (Jonsell et al. 2001).

Like other members of the genus Stellaria, S. alsine possesses a thin, creeping rootstock from which it produces numerous decumbent, ascending stems, not all of which flower (Clapham et al. 1962, 1987). The weak, decumbent or more prostrate stems can layer themselves, particularly after trampling, and towards the end of summer by producing adventitious roots. The species may thus develop quite extensive creeping clonal mats, hiding underneath taller vegetation which by this stage is beginning to die down.

Variation

Plants are variable in habit and in the size and shape of leaves. In damp and shady situations, plants display a more diffuse habit and are less glaucous than those in drier more open sites (Jonsell et al. 2001).

British and Irish occurrence

In Britain, S. alsine is also well represented more or less throughout, but it appears to have declined in the S & E of England since 1950. This is probably due to drainage and agricultural intensification, including a move to more arable farming and the re-seeding of moist pastures. In Ireland, it is widespread and common, but more patchily recorded in the C & W of the island (P.S. Lusby, in: Preston et al. 2002).

Names

The genus name 'Stellaria' is of medieval origin from the Latin 'stella', meaning 'a star', referring to the shape of the five-petalled flower (Gilbert-Carter 1964). The Latin specific epithet 'alsine' is borrowed from a genus name used by Theophrastus for an unknown plant (Gilbert-Carter 1964). Alternatively, 'Alsine' was a name used by Dioscorides for a chickweed-like plant (Gledhill 1985). The previous, and until recent specific epithet was 'uliginosa' which means 'growing in marshy places' from 'uligo', 'inis', moisture, marshy quality (Gilbert-Carter 1964).

The English Common name 'Bog Stitchwort' is a typical, recent, invented, book name of no folklore significance. The 'Stitchwort' part of the name is examined in my Stellaria holostea species account on this website.

Threats

None.

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