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."
vegetation (n.)youdaoicibaDictYouDict
1560s, "act of vegetating," from Middle French végétation and directly from Medieval Latin vegetationem (nominative vegetatio) "a quickening, action of growing," from vegetare "grow, quicken" (see vegetable). Meaning "plant life" first recorded 1727.