E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
in florology, means Good Hope, because it shows the winter is over and spring is at hand. The Athenian girls used to crown themselves with hawthorn flowers at weddings, and the marriage-torch was made of hawthorn. The Romans considered it a charm against sorcery, and placed leaves of it on the cradles of new-born infants.
The hawthorn was chosen by Henry VII. for his device, because the crown of Richard III. was discovered in a hawthorn bush at Bosworth.