This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Gravelly soil is in general characteristic of heaths in the north and west of England, but in the south may be replaced by sand or clay. It is connected in the first case with the formation of moorpan, and trees will not grow on such tracts; but the Pine grows, where the gravel is not cemented together in this manner, on gravelly heaths in East Anglia and elsewhere in the south of England.
Gravelly commons, as indicated by F. A. Lees, have a characteristic flora, which is common also to trap, serpentine, syenitic and granitic rocks, including Trifolium repens, T. fragiferum, T. minus, T. filiforme, Ornithopus perpusillus, Plantago coronopus (also maritime). He points out that similar species occur whatever be the age of the gravel, the same plants occurring even to the Chamomile (Anthemis nobilis) and Bupleurum tenuissi-mum. And much depends on the relative moisture or occurrence of pools. Here are found Starwort, Forget-me-not, Bur Marigold (Bidens cernua), and Pulicaria vulgaris, like the Chamomile now very rare, and more or less confined to commons in the south of England.
In marshy spots occur Ranunculus flammula, R. hederaceus, Nasturtium terrestre, Carda-mine hirsuta, Montia fontana, Peplis Portula, Epilobium palustre, Helosciadium nodiflorum, H. repens, Pedicularis sylvatica, Lvcopus euro-poeus, Mentha hirsuta, M. piperita, M. Pu-legium (the two latter now very local or rare), Polygonum minus, Blysmus compressus, Heleo-charis, Carices.
Others on village greens and dry commons are Polygonum aviculare, Nardus stricta, Chenopodium, A triplex (in waste places), Cerastium, Sagina, Filago, Polygala vulgaris, Hypericum humifusum, Linum catharticum, Potentilla anserina, P. tormentilla, Carlina vulgaris, Chrysanthemum inodorum (Matricaria inodora). Rampion, described here, is also a characteristic plant of gravelly soil.