An annual of wet marshy places, winter-flooded ground beside ponds, lakes and ditches, or damp pastures trampled by stock. It is found on a wide range of soils, from nutrient-rich muds in pastures to sandy and gravelly lake shores. 0-315 m (Skeggles Water, Westmorland).
While there has been little change in distribution since the 1962 Atlas, P. minor is now known from many more 10-km squares. New records from Ireland, S.W. Scotland and Wales increase the known distribution slightly westwards and northwards.
Eurasian Temperate element.
There are no images in this gallery.
Light (Ellenberg): 7
Moisture (Ellenberg): 8
Reaction (Ellenberg): 5
Nitrogen (Ellenberg): 8
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.6
July Mean Temperature (Celsius): 15.2
Annual Precipitation (mm): 1003
Height (cm): 40
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 296
Count of 10km squares in Ireland: 93
Count of 10km squares in the Channel Isles: 1
Atlas Change Index: -0.06
Scarce Atlas Account
Persicaria minor (Hudson) Opiz
Status: not scarce
P. minor has a similar distribution and ecology to its relative P. laxiflora and, indeed, the two species occasionally grow together, often accompanied by P. hydropiper. In southern England P. minor is typical of an open community of Bidens cernua, B. tripartita, Catabrosa aquatica, and with species of Chenopodium and Rumex. This community develops on nutrient-rich muds as the water level of ponds and ditches falls in the latter part of summer. These open conditions may also develop in cattle-poached sites or where peat-cutting removes the surface vegetation. In northern England and southern Scotland it is a plant of gravelly or sandy shores above the normal water level of lakes and in the draw-down zone of reservoirs. P. minor tends to occur in slightly more acidic conditions than P. laxiflora and somewhat more nitrogen-rich sites. Largely restricted to the lowlands in Britain, P. minor is found up to 315 metres at Skeggles Water.
P. minor is an annual, reproducing by seeds and, like P. laxiflora, requiring the open wet-mud habitat with low competition for successful germination.
As for P. laxiflora, past (and present) records have to be treated with caution owing to taxonomic confusion. However, there is considerable evidence for a decline in southern England. This decline follows both the decline of farm ponds and ditches and greater regulation of water levels, reducing the extent of wet mud. However, it was previously under-recorded and since 1962 it has been found in many new sites, especially in Cumbria and south-west Scotland.
P. minor is widespread in Europe between 45 °N and 65 °N, but absent from the arctic and from most of the Mediterranean region (Jalas & Suominen 1979). It extends eastwards to eastern Asia, and is a rare introduction in North America.
J. O. Mountford
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1979)
1981. Docks and knotweeds of the British Isles. Botanical Society of the British Isles Handbook no. 3.
1994. Scarce plants in Britain.