In Greek:
Tree: «Δένδρο» ('ðenðro, n.) or colloquially, «δέντρο» ('ðendro, n.); Classical neuter noun «δένδρον» ('dĕndrŏn)--> tree, PIE base *der-/drew-, wood, tree.
Roots: «Ρίζα/ρίζες» ('riza, f. nom. sing./'rizes, f. nom. pl.); Classical feminine noun «ῥίζα» ('rhīză)--> root; also «ῥίζωμα» ('rhĭzōmă, n., 'rizoma in modern Greek)--> the mass of roots of a tree. PIE base *wrd-, root.
Trunk: «Κορμός» (kor'mos, m.); Classical masculine noun «κορμός» (kŏr'mŏs)--> trunk of a tree, log of timber; PIE base *(s)qer-, to cut.
Bark: «Φλοιός» (fli'os, m.); Classical masculine noun «φλοιός» (pʰlœ'ŏs)--> husk, bark; PIE base *bhel-(2), to inflate, swell.
Branches: «Κλαδιά» (kla'ðja, n. nom. pl.); diminutive of the Classical masculine noun «κλάδος» ('klādŏs)--> branch, shoot of a tree; PIE *kldo-, from PIE base *kel-, to strike, cut.
Leaves: «Φύλλο/φύλλα» ('filo, n. nom. sing./'fila, n. nom. pl.); Classical neuter noun «φύλλον» ('pʰūllŏn)--> leaf; PIE base *bhel-(1), to thrive, bloom, sprout.
Fruits: «Καρπός/καρποί» (kar'pos, m. nom. sing./kar'pi, m. nom. pl.); Classical masculine noun «καρπός» (kār'pŏs)--> fruit; PIE base *kerp-, to gather, pluck, harvest. Colloquially, «φρούτο/φρούτα» ('fruto, n. nom. sing./'fruta, n. nom. pl.), an Italian loan word < frutto.
Flowers: «άνθος/άνθη» ('anθos, n. nom. sing./'anθi, n. nom. pl.); Classical neuter noun «ἄνθος» ('āntʰŏs)--> blossom, flower; PIE base *andh-, to bloom. Colloquially, «λουλούδι/λουλούδια» (lu'luði, n. nom. sing,/lu'luðja, n. nom. pl.), with obscure etymology (either from the Albanian lule-->flower, or from the Byzantine «λειλίδιον» (li'liðion, n.) diminutive of «λειρίον/λειλίον» (li'rion/li'lion, n.)--> the lilium).
Blossoms: «Mπουμπούκι/μπουμπούκια» (bu'buci, n. nom. sing./bu'buca, n. nom. pl). A Byzantine word, diminutive of the Classical masculine noun «βόμβυξ» ('bŏmbūks)--> init. silk-worm, later flower or cluster of flowers. «Βόμβυξ»>«Βομβύκιον»>«Μπουμπούκι». With obscure etymology.
Crown: «Κορώνα» (ko'rona, f.) or «κορώνη» (ko'roni, f.). Classical feminine noun «κορώνη» (kŏ'rōnē)--> init. anything hooked or curved, later, garland, wreath, crown. PIE base *qer-, *qor-, imitative of harsh sounds (especially of the crow's cawing). The curving on the crown resembles the crow's bill.