Flora of Ashdown Forest - Botanical Society of the British Isles

*E1odea canadensis. Canadian waterweed, Canadian pondweed.We have two records from small ponds in Pippingford Park at 444.301, 1993 and448.299, 1995, both SBRS, and both obviously introduced wite other aquatics. It doesnot grow well in acidic, nutrient-poor water which may explain its absence from theForest.3 First recorded in Britain in 1836, and one of the earliest aquatic aliens to beintroduced into Britain from North America. It is locally frequent in Sussex, and is nowrelatively common in Britain (Simpson 1984) and naturalized world-wide.4 5191*E1odea nuttallii. Nuttall's waterweed.We have records from ponds in the Forest Row area, a new pond near Pound gate(484.2881, 1994, SBRS, and new pond west of Old Mill House (482.3031, 1995, TR. Itis significantly more common in the Forest area than E. canadensis but has also not beenreported previously.3 -++-~~~-""'-+- Both Elodea nuttal/Ii' and E. canadensis show a wide range of variation which is4 5mainly due to the growth conditions (Simpson 1988). Only female plants of both speciesare present, and in the summer, pink flowers on long stalks can dot the water surface.E. nuttallii can be easily distinguished as the narrower leaves curl backwards like an armtwisted behind a back.This is a more recent introduction to Britain than the last species, having been first recorded in 1966. It isscattered in Sussex and is increasingly common in England (Rich & Woodruff 1995) and scattered in Scotland, Walesand Ireland. A native of North America.* Lagarosiphon major. Curly waterweed.Pond on the edge of the golf course at Forest Row (436.342), 1993, TR; pond inPippingford Park (450.298), 1992, PW; Ellison's Pond 1462.288), 1993, TR.It is more common now than as noted in the Sussex Plant At/as. A native of SouthAfrica, commonly used by aquarists and increasingly naturalized in England (Rich &3 Woodruff 1995). Also naturalized in a few European countries.Readily distinguished from the Elodea species by its larger size and spirally arrangedleaves (whorled in Elodea).4 5APONOGETONACEAE* Aponogeton distachyos. Cape-pondweed.Hall 119801 gives a pond at Nutley (42N) as the only Sussex locality for this plant.We have four records. One of these is from the same tetrad as Hall's record but thesite, a dammed stream near Lower Misbourne Farm (456.272:1 is not a pond and therecord may have been from Boringwheel Mill pond to which we have not had access. It3 'IS well-established in the main lakes at Pippingford, where it was probably planted but isnow naturalized, 1993 +, SBRS.4 5A native of South Africa, frequently planted in ponds and naturalized in scatteredlocalities in Britain.JUNCAGINACEAETriglochin pa/ustre. Marsh arrowgrass.On the bogs on Ashdown Forest, not uncommon (Forster 1816; no specimen in BM).This species of wet grassland, ditches and heathland flushes has not been recorded again, and we wonder if theoriginal record was correct though it is difficult to see with what it can have been confused. It is a very uncommonplant in Sussex, but has been recorded on St Leonard's_ Forest (Hall 1980).Widespread in Britain but commonest in the north and west, and in Europe except the Mediterranean region. Italso occurs in North Africa, northern Asia, North and South America and Greenland.POTAMOGETONACEAEThe monograph of the British species by Preston 11995) is now the standard guide but was not published until we hadfinished our survey! It might have helped to clarify some of the problems we have had distinguishing plants of P.natans and P. polygonifo/r"us from dried-up ponds during the 1995 drought.