Stellaria palustris

Taxonomy 

Name: Stellaria palustris Retz.

Common name: Marsh Stitchwort.

Synonyms

  • S. dilleniana Moench, non Leers
  • S. glauca With.
  • S. parviflora (Kl. & Richt) Druce.

Fl. Nordica finds the species very variable, giving six ‘entities’, though raising none to even varietal status, separating on height, habit, degree of branching, length of internodes and branches, leaf texture, density of inflorescence and flower size. Hybrids – none known in BI but with S. graminea in Fl. Nordica.

Chromosome No.: 2n = c.130 (Clapham, Tutin & Moore 1987; Stace 2010); 2n =182, 10- to 14-ploid (Fl. Nordica).

Stellaria palustrisStellaria palustris

Photography: R. Stokes

Identification 

The flowers are intermediate between S. holostea and S. graminea. It differs from the former by the leaves being waxier, with petals cleft to the base and three-veined sepals, and from the latter by the glabrous bracts and sepals, and by its greyness rather than greenness. Apart from the usually distinctive colour of the aerial parts, S. palustris grows up to a height of around 60 cm and has larger flowers than S. graminea, the only species with which it might possibly be confused, although the latter prefers better drained soils. Walters (1985) draws attention to a green (rather than glaucous) variant that occurs at Woodwalton Fen and possibly elsewhere, and may well be overlooked.

Distribution 

Widespread in eastern and southern England, as well as central Ireland, but rare in Scotland and Wales. As a member of the European Boreo-temperate element, it is quite widespread in northern Europe, eastwards to Russia, and extending southwards at least to the Alps and the Carpathians, but very uncommon south of these. Widely naturalised outside its native range (Hultén & Fries 1986; Jalas & Suominen 1972-1999).

BSBI Hectad Map 

Click on the map to view full-size on the BSBI Maps Scheme website.

Ecology 

A species of damp and wet places, including pastures, grassy fens and marshes, especially in areas with standing water in winter. This is provided in fens, meadows, pastures and scrub, primarily around the larger lakes, but occasionally also by rivers, streams and ditches. It is also able to colonise artificial habitats such as old peat diggings. It is included in the following NVC communities: M22 Juncus subnodulosus fen-meadow, S24 Phragmites australis fen and S27 Carex rostrata tall-herb fen (Rodwell 1991, 1995).

Status 
  • Origin: native.
  • Rarity: although it does not qualify as Nationally Scarce, it is found in only 2.28 tetrads per hectad in a sample of 19 recent tetrad floras - considerably lower than its hectad distribution would imply (Pearman, in press).
  • Threat: it has suffered a marked decline (Change Index -0.89). Many sites were lost in C. & E. England before 1930, and losses have continued in most parts of its British range. However, some recent floras, based on recent work (Norfolk, Somerset) rather than on surveys over many years (Hampshire, Oxford), give no particular hint of decline, merely stating that it is always an uncommon plant. In other apparent centres (Cambs, Hants, Suffolk, Surrey and Berks) the most recent Floras also describe it as rare and decreasing. There are many recent records from Ireland, but we have little idea of its frequency below hectad level, or the trend there, other than in Co. Fermanagh, where the draft forthcoming Flora states that although frequent in its core area, at several of the outlying stations recorded in the 1950s or earlier, it seems to have disappeared, as there are no post-1975 records for them.
  • Conservation: most county recorders list it as an axiophyte.
Further Work 

The vegetation communities listed for it in Rodwell (1991-2000) seem insufficient, possibly because, as a fairly rare plant, it was found in few samples. A dedicated study of its vegetation and habitats might therefore provide useful insights into its ecology and conservation. Taxonomically, it seems a little unstable. Subspecies and/or varieties might be worthy of further investigation, and the range of chromosome counts published for it suggest that there are various ploidy levels. To be more certain about any threat it faces in Britain, we need more detailed studies of its distribution and abundance within sites. It also appears to be under-recorded at the hectad scale, to judge from the Maps Scheme maps.

References 
  • Walters, S.M. 1985. Stellaria palustris - a declining, or an overlooked species? Nature in Cambridgeshire.
Citation 
Pearman, D.A. (date accessed). Species account: Stellaria palustris. Botanical Society of the British Isles, www.bsbi.org.uk.

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