This was either the title of the Roman goddess Minerva/Athene** and others; or the name of some unknown botanist (W.P.U Taylor)
hippo, = horse;
-ius, = means 'characteristic of', hence indicates connexion or resemblance. (Ch, Ox, BL)
frutex, = a shrub, bush;
-escens, = indicates process of becoming, hence not fully achieved resemblance, often expressed by the termination ‘-ish’.
frutesco, = to put forth shoots, to sprout, become bushy.
(becoming shrubby) (ld, BL)