Flora of Ashdown Forest - Botanical Society of the British Isles

*Senecio x albescens (S. cineraria x jacobaea).Disturbed verge with S. cineraria near Ashdown Park (429.323), 1993, TR & EL, possiblyimported with soil rather than originating in situ, but not persisting. It is occasionallyrecorded in Britain near habitation where S, cineraria is cultivated,•3-++-------~+-1874 5Senecio jacobaea. Common ragwort.Recorded in every square. Frequent on roadsides, but much rarer on the heaths and thenusually on the rides or on imported soil used to make up the paths. It mysteriously disappearsshortly after coming into flower on the verges as it is controlled on some of the chases byhand pulling (AFN 30:31. which usually takes about 4-5 years to eradicate it.The plant contains alkaloids which are poisonous to most herbivores except somespecialist invertebrates. Defoliation by the striking black-and-orange cinnabar moth larvae canmarkedly affect its seedling establishment, rosette growth and flowering. The effects aremost pronounced when defoliation occurs in combination with unfavourable weather such as adry spell. It is often abundant around warrens as it is not eaten by rabbits, and selectivegrazing of other species can give the ragwort a competitive advantage as well as creating the open ground that it needs toregenerate in (Prins & Nell 1990).Ragwort has been introduced to New Zealand where it is a serious weed, and there have been attempts to control itwith cinnabar moths sent from England (Imms 1947). Initially the moths did well but then slowly declined, reputedly dueto predation by birds. The bright colours of the larvae - which in England would be a warning to birds - were ignored andthe local birds gorged themselves until they couldn't fly! Another possible reason was that a native parasitoid of anindigenous moth also parasitised the cinnabar moths (Samways 1981). Another insect, the ragwort seed-fly, was also sentwith better success.Recorded in 98 % of the tetrads in Sussex (Hall 1980). Widespread and increasing in England (Rich & Woodruff1996), and widespread in Europe and western Asia.Senecio aquaticus. Marsh ragwort.Tetrads 33W, 42N and 43L (Hall 1980).Millbrook Farm area (43.29), 1994, SBRS (AK, AH, etc.). Amazingly rare for a plant ofwet acidic grasslands, but it does seem genuinely to be very scarce in this part of Sussex.Locally frequent in the Weald and along major river valleys in Sussex. Widespread inBritain, especially in the west, but decreasing probably due to drainage of wet meadows (Rich& Woodruff 1996). West, central and southern Europe.4 5Senecio erucifolius. Hoary ragwort.Common on the Forest (Hall 1980).Usually as scattered clumps on road verges and more frequent on clayey soils. OK iscareful not to pull this species when pulling common ragwort, and its apparent frequencycompared with common ragwort increases markedly during the flowering season as the3 ragwort is pulled up and eradicated!Common in Sussex. Widespread in lowland south-east England, and in Europe except inthe north and parts of the west. Also in western Asia.4 5*Senecio squalidus. Oxford ragwort.One plant near gate noted during the annual flower show at Lines Farm (444.344), 1995, PW,probably trampled to death later 'In the day unnoticed by the visitors!This plant was introduced to Oxford Botanic Gardens and escaped over the wall in 1794and onto the railway lines and spread through Britain very quickly, Salisbury (1961) noted3 that the spread was "markedly discontinuous with respect to the more remote infections,whilst at the same time spreading locally around each new station". It is mainly established inthe Brighton area in Sussex and is more scattered elsewhere.4 5 Widespread in lowland south-east England. It is an endemic of the mountains of centraland southern Europe.