flora: [16] Latin flōs meant ‘flower’ (it was the source of English flower). From it was derived Flora, the name given to the Roman goddess of flowers. English took over the term in this mythological sense, and in the 17th century it began to be used in the titles of botanical works (for example John Ray’s Flora, seu de florum cultura ‘Flora, or concerning the cultivation of flowers’).
In particular, it was used for books describing all the plants in a particular area or country, and in the 18th century it came, like its animal counterpart fauna, to be applied as a collective term to such plants. The adjective floral [17] comes from Latin flōs. => flower
