Flora of Ashdown Forest - Botanical Society of the British Isles

67DROSERACEAEDrosera rotundifolia. Roundwleaved sundew.Bogs of Ashdown Forest, plentifully (Coleman 1836), On the bogs on Ashdown Forest,near Chuck Hatch and elsewhere (Done 1914), Boggy heathland, Ashdown Forest, 1970,• D, p, Young (BM), Abundant in bogs south of Forest Row, 1948, R, A, Boniface, Eleventetrads on the Forest (Hall 1980). Present on most ditch sides near Royal Ashdown golf3 course club house, colonising bare soil, 1987 + t PS.It was recorded from fifteen squares during recent survey work. In most of these itoccurs in several discrete patches, on bare ground in wet areas or amongst Sphagnummosses. Populations survive on some well-used paths and rides where there is a little4 5 disturbance. Some populations may well have been lost with habitat changes in recentyears. Valentine (1979) noted that sundews can reproduce vegetatively by adventitiousbuds which develop on the leaves in late summer and autumn.D. rotundifolia is frequent in the north and west of Britain. It is found elsewhere in Europe from Iceland andnorthern Scandinavia to northern Spain. It also occurs in temperate Asia, Japan, Greenland and North America. It isusually confined to areas with a high water table or high rainfall and humidity. It does not often occur in open pools, asD. intermedia can, but it is frequent at the edges of pools amongst bryophytes.Sundews are carnivorous plants. Invertebrates are attracted to the shiny glands at the ends of the tentacles on theleaves. They become stuck to the sticky secretions, and then trapped as first the tentacles and then the whole leaf foldtogether. The plants benefit from absorbing nutrients from their prey, particularly phosphorus and nitrogen, which arelikely to be deficient in their soils. They can survive without catching any prey, but under experimental conditions feedingthem has shown increased biomass, number of leaves, seeds and weight of seeds (Crowder et al. 1990).Drosera intermedia (D. longifolia). Oblong-leaved sundew.• •] -++-''"-c..------'-+_4 5Near Forest Row (Cooper 1835), Bogs of Leg's Heath, Ashdown Forest (Coleman 1836),Near Forest Row (Deakin 1871), Ashdown Forest near Nutley, M, R, Dixon, 1886 (Arnold1887), Ashdown Forest, 1894, H, Farr (BM), Bog near the rifle range, Forest Row, Miss p,Stockdale (a specimen in BEX is labelled East Grinstead, August 1911 but surely must relateto Forest Row); Quabrook Common between Hartfield and Forest Row, 1817, E. Forster,and seen by Wolley-Dod in 1937; between Pippingford Park and Chelwood, E, Ellman;between Chelwood and Nutley, E, H, Farr; bog north of Gills Lap, E, D, Morgan (Wolley-Dod1937). Frequent in bogs east of Broadstone Warren, 1948, and ncar Nutley, 1957, R. A.Boniface, Tetrads 42J, 42P, 43F and 43H (Hall 1 980),Trampled ride east of the Isle of Thorns with Rhynchospora (423,304), 1988, CM, and 1993 +, TR et ai, butdeclining as the area re-vegetated; ride in the grazing area (444.296), 1983 +, CM and still present 1994, TR & PA butthe site appears to be drying up in recent years; large population on small footpath leading west from the A22 on theslope below Millbrook west (438.294), 1983 +, CM but the path has grown over and there was no sign of it in 1995,but another population of 100 plants was found to the south with Rhynchospora (438.292), 1994, PW; Broadstone Trailnear the pile bridge with Rhynchospora (441.327), 1994, AK but only a single plant in 1995 declined for no obviousreason, NM & CM; bare soil on areas stripped of turf on practice range in 1987, and holding own in quite closed turf forseveral years, 100 metres south of golf course club house (431.341), still present in 1994, PS.Drosera intermedia appears to be declining on the Forest, possibly due to changes in management and trampling, orto changes in ground water levels. There is a fine balance between the level of trampling required to maintain thenecessary open patches and erosion which is too heavy. It has gone from the wet heath north of Goat car park(403,327), 1986, FR (Coleman's site) which is now more heavily used, This together with the loss of the Millbrook westsite shows just how important the balance of trampling pressure is for keeping sites open for this species.It is primarily a plant of sites which are flooded in winter and subject to drying out in summer, although it is alsowidespread in bog pools. The sites on the Forest which appear to have been lost recently were possibly relatively drycompared to typical habitats.D. intermedia is scattered and local in distribution in England and Wales, where its decline is blamed on drainage. Itis a more lowland plant than D. rotundifolia and D. anglica in Britain, reaching only 350 metres altitude in Scotland and335 metres in Ireland. It also has a more restricted European distribution, being absent from northern Scandinavia andrare in eastern Europe (Crowder et al. 1990). It also occurs in Asia Minor and North America.VIOLACEAE* Viola odorata. Sweet violet.Recorded in tetrad 42T in Hall (1980), probably as a garden escape, but not seen by us.It tends to grow best on more calcareous soils and may not persist on the acidic Forest soils. In southern Europe itoccurs in natural habitats such as alluvial woodlands and scrub but becomes less frequent in them in the north. It isclearly native in the Mediterranean and has been introduced as a medicinal and ornamental plant elsewhere.