Flora of Ashdown Forest - Botanical Society of the British Isles

Potentilla anserina. Silverweed.Common on the Forest (Hall 1980).It is frequent in damper patches on rides and wet grassland, but not on the most acidicsoils or in some of the more heavily wooded areas.The life cycle of this species probably depends on the size of individual plants, andvegetative spread is probably more important for population increase than seeds (Eriksson1988), Plants pass the winter as a rhizome with the bud at the soil surface, and the leavesdevelop in the spring. Small rosettes may simply grow all summer. In June and July, somerosettes above a critical size produce flowers, The flowers are insect-pollinated and selfincompatible,but fruit production is commonly limited by availability of pollen. Between Julyand September the bigger rosettes produce stolons which root and give rise to daughter rosettes, but this uses a lot ofresources. A few rosettes both flower and produce stolons. In the autumn the stolons wither leaving isolated daughterplants, and the cycle begins again the next year.Its prime habitats are shores of lakes, rivers and seas, and it also occurs in man~made habitats such as meadows,roadsides and on waste ground. Ubiquitous in Sussex and Britain, and widespread in Europe except for much of the southand in Asia.99*Potentil/a recta. Sulphur clover.Forest Row, 43M (Hall 1980).On the path between Nutley and Fairwarp church (45.27), 1995, RN (det. PH), lookingvery out of place in a bramble bush with Alchemilla mollis and Geranium x oxonianum.A garden escape originally from Eurasia and North Africa, now widely established insouthern and eastern England. It is a very variable species.Potentil/a erecta subsp. erecta. Tormentil.Common on the Forest (Hall 1980).We have recorded it in every square in grassland and heathland.Widespread but decreasing in Britain (Rich & Woodruff 1996), and widespread in Britain,Europe and Asia.Potentil/a x suberecta (P. erecta X anglica).Near Wych Cross, C. E. Salmon (Wolley-Dod 1937).All three records were made in 1995 by TR whilst specially looking for hybrids, and itgenuinely seems to be quite rare on the Forest. These hybrids form few fruits, rarely root atthe nodes and have entire or deeply cut stipules but they are not easy to determine (seeHarald in Rich & Rich 1988). It seems to be much rarer than P. x mixta, possibly becauseone parent, P. anglica, is rarer and their distributions correlate well.It apparently is quite widespread in Britain where the parents occur together.Potentil/a anglica (P. procumbens). Trailing tormentil.This species is reputedly often confused with P. x mixta and P. x suberecta and Hall (1980)suggests it may be frequent in ~ussex but the data are too inadequate to be certain.We had few records until 1995, when plants were specially looked for; only fertile plantswere accepted by TR. It occurs on mildly acid soils in unimproved meadows, edges of roads,and tracksides, often in open vegetation.It is probably quite widespread in Britain in the west and in areas with acidic soils, and ismainly western in Europe. It also occurs in Madeira and the Azores.