I'm a Riddle in Nine Syllables

I'm a riddle in nine syllables, An elephant, a ponderous house, A melon strolling on two tendrils. O red fruit, ivory, fine timbers! This loaf's big with its yeasty rising. Money's new-minted in this fat purse. I'm a means, a stage, a cow in calf. I've eaten a bag of green apples, Boarded the train there's no getting off.