This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The present range of Hop Trefoil - for this is only known in the present-day flora - is the North Temperate Zone of Europe, North Africa, North and West Asia, and it is also an introduction in North America. In Great Britain it is unknown in Monmouth, South-east York, Main Argyle, Hebrides, Orkneys, elsewhere it grows from Ross southwards, ascending to 1200 ft. in Derbyshire, Ireland, and the Channel Islands.
The Hop Trefoil, while commonly a meadow plant, is also a frequent associate of species that delight in the more or less undisturbed security and protection of the railway banks, which are now so general a feature of most districts.