The genus Allium (alliums) is characterised by herbaceous geophyte perennials with true bulbs, some of which are borne on rhizomes, and an onion or garlic odor and flavor.^[16]

The bulbs are solitary or clustered and tunicate and the plants are perennialized by the bulbs reforming annually from the base of the old bulbs, or are produced on the ends of rhizomes or, in a few species, at the ends of stolons.^[17] A small number of species have tuberous roots. The bulbs' outer coats are commonly brown or grey, with a smooth texture, and are fibrous, or with cellular reticulation. The inner coats of the bulbs are membranous.

Many alliums have basal leaves that commonly wither away from the tips downward before or while the plants