florayoudaoicibaDictYouDict[flora 词源字典]
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[flora etymology, flora origin, 英语词源]
flora (n.)youdaoicibaDictYouDict
c. 1500, "Roman goddess of flowers;" 1777, "the plant life of a region or epoch," from Latin Flora, "goddess of flowers," from flos (accusative florem, genitive floris) "flower," from *flo-s-, Italic suffixed form of PIE *bhle- "to blossom, flourish" (cognates: Middle Irish blath, Welsh blawd "blossom, flower," Old English blowan "to flower, bloom"), extended form of *bhel- (3) "to thrive, bloom," which is possibly identical with or derived from *bhel- (2) "to blow, swell" (see bole).

Her festival, the Floralia, was April 28 to May 2 and featured "comic theatrical representations" and "excessive drinking" [Century Dictionary]. The French Revolutionary calendar had a month Floréal (April 20-May 20). Used as the title of systematically descriptive plant catalogues since 1640s, but popularized by Linnaeus in his landmark 1745 study of Swedish plants, "Flora Suecica."