Persicaria minor

Tracheophyta MagnoliopsidaPolygonaceaePersicariaPersicaria minor

Ecology

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).

Status

Native

World Distribution

Eurasian Temperate element.

Broad Habitats

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

Annual

Life Form - primary

Therophyte (annual land plant)

Woodiness

Herbaceous

Clonality - primary

Little or no vegetative spread

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

JNCC Designations

NHMSYS0000461606

Scarce Atlas Account

Scarce Atlas Account: 

Persicaria minor (Hudson) Opiz

Small water-pepper

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

Atlas (176a)
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1979)
Lousley JE, Kent DH
1981.  Docks and knotweeds of the British Isles. Botanical Society of the British Isles Handbook no. 3.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.