Flora of Ashdown Forest - Botanical Society of the British Isles

226Iris pseudacorus. Yellow iris, Yellow flag.Frequent on the Forest (Hall 1980).We have recorded it frequently by ponds and streams, the bright yellow flowersconspicuous in early summer, It tends to occur in the wetter patches in meadows and on theedges of ponds, but not in deeper water. [t is probably planted in some ponds.It typically grows on soils with a high water content and is fairly tolerant of anoxicconditions, but it does not need to be submerged and can grow in some dry sandy soils. Thesoils vary from pH 3.6-7.7, but it has a high nitrogen requirement. It occurs in a range ofmire and open woodland types, usually forming patches; after flowering the rhizome's4 5 terminal bud dies and growth is resumed by two lateral buds producing dense stands. Therhizomes degenerate after 6-15 years resulting in separation of clonal patches (Sutherland 1990).Common in wet places in Sussex and throughout lowland Britain. It occurs in Europe, western Asia and North Africa.*/ds versic%r. Purple iris.Pond at Tompset's Bank (424.338), 1995, PW, with either I. pseudacorus or a hybrid.A frequent garden escape in Britain. Native in North America.4 53 -++------'--t-*Crocus vernus. Spring crocus.Goat car park (402.326), 1995, TR & JK. Plants with deep purple flowers occur plantedoutside a number of gardens and in churchyards, but can scarcely be considered asnaturalized.We have also found leaves at a number of sites on the Forest, but have had no flowers3-++------'-+- to confirm identification. A mass of Crocus was reported as appearing in clumps on a trackrepaired with imported topsoil, B. Willard (AFN 16: 16-17).Widely established as a garden escape or planted in Britain. Decreasing in England (Rich& Woodruff 1996). Native in central and southern Europe.4 5*Crocosmia x crocosmiiflora (Tritonia x crocosmiiflora). Montbretia.Frequent on the Forest (Hall 1980).Widespread around the Forest, well-established and spreading vegetatively in manywoodland and wood edges.Widely naturalized in Sussex, especially in the Weald, and in Britain. It originated in3 cultivation.4 5DIOSCOREACEAETamus communis. Black bryony, Poison-berry.Widely dispersed in hedges, ancient and secondary woodland, and sometimes heathlandedges, including one plant at the Airman's Grave. It occurs mainly round the edges of theForest. It has been suggested to be a poor colonist and to occur predominantly on calcareoussoils, but our plants behave differently.Recorded in 92 % of the tetrads in Sussex (Hall 1980). Locally abundant in England andWales north to Cumbria, the only British representative of the yam family. Widespread insouthern and western Europe and Asia Minor, with Britain as its northern limit.