Flora of Ashdown Forest - Botanical Society of the British Isles

220SPARGAN IACEAESparganium erectum. Branched bur-reed.Six tetrad records (Hall 1980).In ponds and along slow-flowing streams, especially along Millbrook through PippingfordPark. There are four subspecies, of which subsp. neg/ectum has been recorded from pondson Stone Hill and south-west of Mudbrooks House, 1995, TR. The other subspecies could4 5occur as they do not differ in ecology but they have not yet been recorded (Cook 1962).Branched bur-reed is a perennial plant of swampy, wet places in water up to 1 metredeep, but it cannot tolerate desiccation (Cook 1962). It shows little preference for water orsubstrate quality, and is equally at home along the Medway and in the acidic, nutrient-poorponds on the Forest. It does not tolerate deep shade or fast-running water and so is usuallyfound on the more open, slow parts of streams. Spread by seed is apparently not common, but must be the mechanism bywhich it has reached many of our isolated ponds. Seeds pass though waterfowl unaffected, and they may float for morethan a year. The bur-reed is palatable to stock and may have spread on the Forest since grazing was reduced.It is widespread in Sussex and is locally frequent by ponds and in streams. Widespread in lowland Britain andtemperate regions of the northern hemisphere.Sparganium emersum. Unbranched bur-reed,Bogs on Ashdown Forest (Coleman 1836). Tetrads 42N, 42T, 43H and 43K (Hall 1980).Now confined to the north side of the Forest; minor stream 150 metres east of golfcourse clubhouse (433.341), 1995, TR & PS; Pippingford Park, frequent in stream bedupstream of Centre Bridge for c. 300 metres (449.316-452.313), 1995, TR & HP; stream3 --++---~~~---L+- near Hart's Farm (461.332), 1994, TR & SR.At Pippingford Park the plants that were exposed during the dry summer of 1995 haderect leaves rather like S. erectum but only about one third of the size, and flowered andfruited well. Plants in deep or swiftly-flowing water usually remain sterile (Cook & Nicholls4 51986), and some vegetative plants in the Medway on the drive to Ashdown Farm (443.349),1995, TR & PA may also be this species.It is usually found in permanent water 20-80 cm deep and is tolerant of rapid changes in water level. It occurs in stillor flowing water, and can withstand spates. Individual leaves have been found to last only 31-39 days. It usually occurson clay or fine sandy substrates, and can be frequent on silt. It is most common in mid- to high-nutrient water but willgrow in nutrient-poor water as on the Forest (Cook & Nicholls 1986).It is occasional in Sussex and is widespread in lowland Britain. It is widespread in temperate regions of the northernhemisphere.TYPHACEAETypha latifolia. Greater reedmace, Bulrush, Common cat's-tail.Six tetrad records on the Forest (Hall 1980).Found mainly in ponds, marl pits and along the edges of lakes, but also in relatively dryditches, and sometimes in wet patches in woodland (49.33). It occurs in a range of waterand substrate types, but generally in locations that are wet in winter and dry in summer. It3 forms big patches and excludes most other species.Common in Sussex and England, rarer in Wales and Scotland. Widespread in thenorthern hemisphere and the tropics.4 5PONTEDERIACEAE*Pontederia cordata. Pickerelweed,] ++--___ ....L\__4 5One plant in a new pond west of Ellison's Pond (462.287). late August 1995, AK. The plantwas not there in June; this fact, together with the presence of one of the plastic containersused by garden centres for water plants close by in the same pond, leaves little doubt aboutthe source of this plant!Pontederia cordata is a rather attractive native of eastern North America and is widelyavailable in garden centres. It is still relatively scarce in the wild, currently being known fromonly two other localities in Sussex. Once present it does seem to persist so we can expect itto remain in this site for some time unless someone decides to reclaim it for their gardenpond.