A sermon preached on Whit Monday in St. Catherine Cree, when all the congregation wear flowers.
Flower sermons are now (1894) preached very generally once a year, especially in country churches. Every person is supposed to bring a bunch of flowers to the altar, and the flowers next day are sent to some hospital.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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