Flora of Ashdown Forest - Botanical Society of the British Isles

60Persicaria amphibia (Po/ygonum amphibiumj. Amphibious bistort.Tetrads 43A and 43H IHall 19801.Surprisingly rare given the number of ponds with base-poor, medium-nutrient water, andonly recorded in 47.26, 1994, Flora meeting Idetails not recollected and possibly an error),One of the few truly amphibious plants in Britain, occurring in permanent water and on3 -++------'-+_ dry land though often not flowering in the latter case. Common in Britain and increasing (Rich& Woodruff 1996), and widespread in Europe, Asia, Africa and North America.4 5Persicaria maculosa (Polygonum persicariaj. Redshank, Lover's pride.Frequent on roads ides especially in the gutters, on pond edges, in the villages, car parks andarable fields, etc., often on reasonably nutrient-rich soils. It is only occasionally found inwoodland rides and does not appear as shade-tolerant as P. hydropiper. Whilst most plantsexamined have lacked glands, a few with glands scattered on the pedicels were treated asthis species and not the next.Recorded in 90% of the tetrads in Sussex (Hall 19801. Common throughout lowlandBritain and Europe, and widespread elsewhere in the world as a weed.Persicaria lapathifolia (Polygonum lapathifolium). Pale persicaria.Common on the Forest IHall 19801.Possibly under-recorded on the Forest. This and P. maculosa frequently grow togetherbut the differences are not always immediately obvious; P. lapathifolia is certainly lesscommon. It is found on the edges of roads, in gardens and in arable fields. It was abundant3 --+.--------'_+_ at the organic farm at Plawhatch in 1995.Common in Sussex and lowland Britain, and possibly increasing in England (Rich &Woodruff 1996). Probably more widespread in Europe than P. maculosa. Found in temperateregions of the northern hemisphere and in South Africa.4 5Persicaria hydropiper (Polygonum hydropiper). Water-pepper,Common on the Forest IHall 19801.Most typical of wet patches on shaded rides and often abundant on them. It is especiallyfrequent in damp muddy hollows where the soils are silty and compa~ted, and it is largelyabsent from the heathy, acidic soils. It has a persistent seed bank and 4% of the seeds maystill be viable after 50 years ISalisbury 19701.Young plants can be distinguished from P. maculosa, with which it may grow, by thepeppery taste as the English name hints.Common in Sussex, Britain, lowland Europe, temperate Asia snd North Africa.Persicaria minor (Polygonum minus). Small water-pepper.Near Rifle Butts, Forest Row, Miss P. Stockdale IBEX; Wolley-Dod 19371; this site was probably at about 425.337 andwas drained for the golf course.Probably extinct. This is a species of wet grassland, swamps and pond edges, often on nutrient-rich mud which driesout in summer (Mountford 1994). Plants produce both flat and trigonous seeds in varying proportions which differ in somegermination characteristics, though both germinate best in the spring and in the light (Salisbury 1970).Scattered thinly over the southern part of Britain and always scarce in Sussex, particularly so in the east. Quitewidespread in Europe except the extreme north and south and temperate Asia.Polygonum aviculare sensu stricto. Knotgrass, Armstrong.Quite frequent in car parks, on road edges, field edges and villages, but very uncommonanywhere else.Virtually ubiquitous in lowland Europe, and temperate Asia.P. aviculare s.s. and P. arenastrum have often been recorded as an aggregate in the past,but they are readily distinguished. P. aviculare is a sprawling plant with a variety of leaf sizes,and the fruit has three equal sides. P. arenastrum is a more compact plant with mainly equal,small leaves except at the tips of branches, and the fruits have two equal sides and a smaller,concave one.