Flora of Ashdown Forest - Botanical Society of the British Isles

75*Rorippa sylvestris. Creeping yellow-cress.Tetrad 42Z (Hall 1980).Weed in imported soil, Pippingford Park (444.3031. 1993, TR; weed in vegetable patcharound old well, Fairwarp (469.268), PD & RN, 1995; weed in drive, Marsh Green(465.3331. 1994, PC, HP & Hazel Pollard.J ++------"'-------Lf- Scattered in Sussex and Britain. Native in Europe, and now widespread through theworld.A variable species, with two main chromosome races; tetraploids are probably thenative form on river banks, shingle and lake shores, whilst the larger more robust hexaploids4 5are widespread as persistent weeds,Armor8cia rusticana. Horse-radish.Four tetrads in Hall 11980).We have recorded it three times probably where it persists as a garden escape. Thegrated root is used for horse-radish sauce - beware of fresh material which is considerablymore potent than the processed versions!J ++-------'-1- Widely introduced in Sussex and lowland Britain and possibly native in south-eastEurope and western Asia. It is largely sterile and spreads vegetatively.4 5Cardamine amara. large bittercress.,---,---------';-, Tetrad 43L (Hall 1980).J -++--..... :---'-+-4 5Widespread and locally abundant, as for instance at Newbridge bog where a typicalplace to find it is around the edge of an iron flush or on the stream bank.It can be confused with C. pratensis but has blackish-purple anthers, and the stemstend to creep and root at the nodes to form small patches. It is rarely fertile {possibly as it isself-incompatible), and the fruits that were seen at Newbridge in 1995 were predated byinsect larvae. Plants at Friars Gate were also found in fruit, PW,It is occasional in the Weald, and is remarkably rare south-west of a line fromPortsmouth to Liverpool and in north-west Scotland. It is widespread in Europe."C:.:a"r.::d::;-8:..:m:..:i::n::e=p::r::8:=-te::n",s::,.::·s,-.-,C:;""c:.:;koo-flower, lady's smock, Milkmaids.Common on the Forest (Hall 1980).Recorded in most squares, though absent from the more acidic parts and heathland.Locally frequent in old woodland and meadows, probably as different genotypes. A veryvariable plant in Britain and Europe where it is widespread. It also occurs in northern Asiaand North America.4 5Cardamine x fringsii (C. flexuosa x pratensis, C. x haussknechtiana). Bevan's bittercress.One plant with very pale pink flowers was found by DB with both parents in 1994 atHorneastle Wood (394.315), but did not persist into 1995.This hybrid may be quite overlooked in Britain - plants of C, pratensis with small flowerswhich may be pale pinkish-purple or white should be examined carefully and compared with3 local populations of both parents. It appears to originate from local populations where theparents meet (e.g. Bevan & Rich 1991).4 5