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.
Indications of heath or grass heath are occasionally to be found amidst meadow and pasture of a less special type, or purely neutral grassland. It may be that the one has invaded or obliterated the other owing to induced or artificial conditions. This is an interesting problem for the pupil, and will show how one type of formation may influence another.
The flowering plants that may be found as vestiges of former heathland or grass heath are more likely to be discovered, and are easier to distinguish than cryptogams. Such vestiges may, however, as in the case of bogs, be indicated by the occurrence of certain ericetal mosses or other cryptogams that are perhaps the only indication that is left of the former occurrence of a heath flora.
Furze itself, may in some cases indicate heath conditions, especially when associated with Grassy Stitchwort, Heath Bedstraw, Water Pepper, Procumbent St. John's Wort, Sieglingia decumbens, etc.