Flora of Ashdown Forest - Botanical Society of the British Isles

59*Saponaria officinalis. Soapwort, GiII~run~by~the~street.,---;---::==-----,----, By Chelwood Vachery (c. 433.3021, 1994 +, Flora meeting. During the 1995 drought, thepatch remained green all summer.This species was apparently once commonly cultivated near wool mills and the soapyextracts from its leaves and roots used for washing wool (hence the name). When the leaves3 -I-+--~----'-+-- are rubbed between hands they produce a soapy, green slime which needs washing off athome. The slime is formed by chemicals called saponins which are found in many plants andwhose natural function may be to provide resistance to fungal attack (Osbourn 1996).4 5Scattered in Sussex where it is a persistent garden escape on roadsides, etc.Widespread in lowland Britain, native in Europe but not in the north, and Asia.POLYGONACEAEThe definitive identification guide is the BSBI docks and knot weeds handbook (Lousley & Kent 1981), but the nomenclatureand sequence have been updated here.*Persicaria campanulata (Polygonum campanulatum). Lesser knotweed.Planted and spreading in Maskett's Wood (428.285), 1995, TR; established garden escapeoutside house at Isle of Thorns (417.3071, 1995, TR & PA; bank by garden at Nutley(445.276), 1995, AK; St John's area (50.321, 1994, Flora meeting.A native species of the Himalaya, originally introduced in about 1910 and now3 naturalized in Scotland and Ireland in damp shaded places. Semi~naturalized in England andWales and increasing (Rich & Woodruff 1996). It has dimorphic flowers which may accountfor lack of seed-set, and it spreads mainly vegetatively (Conolly 1977).4 5*Persicaria wallichii (Polygonum polystachyum). Himalayan knotweed.A275 near Wych Cross (41.31 I, 1988, PW and 1993, Flora meeting; naturalized by stream ondrive to Old lands Hall (478.277), 1995, TR +; naturalized outside garden, Campfields Rough(470.2801, 1995, ER & RN. Also reported in 1993 but not localised, from the A26 in thePoundgate - Heron's Ghyll area.3 --++-___---L+__The history and spread of this species in Britain has been documented by Conolly(1977). As the name implies it is native in the Himalaya, and well-naturalized in westernBritain. It usually spreads vegetatively from plantings or garden throw-outs; at some sites it4 5covers acres of ground and seems to do best where sheltered from frost. Rarely naturalized inSussex (Hall 1980), but certainly spreading in Britain (Rich & Woodruff 1996).*Persicaria bistorta (Polygonum bistorta). Common bistort.Tetrads 42E, 42N and 43L (Hall 1980).Recorded on a hedgebank, Horncastle (393.311), 1993 +, DB.Probably introduced in south-east England and usually found near houses on the sides ofditches, streams and in damp grassy places. In northern Britain it is often found in damp3 -I-+---------.J'+_ meadows where it could be native. Widespread in Middle Europe, especially in damper andupland areas, Asia and Japan.4 5*Persicaria amplexicaulis. Red bistort.Established garden escape outside house at Isle of Thorns (417.3071, 1995, TR & PA.This Himalayan species is widely grown in gardens. It is rarely naturalized in south-eastEngland but more widely so in the west of Britain and Ireland. It does not appear to set seedin Britain.3 -I-,""--------'+_4 5