Herbarium rhymes with:
barium, aquarium, barium, honorarium, merriam, planetarium, aquarium, atrium, auditorium, bacterium, barium, crematorium, delirium, deuterium, disequilibrium, emporium, equilibrium, honorarium, merriam, miriam, moratorium, myriam, mysterium, opprobrium, planetarium, tellurium, thorium, yttrium