Allioideae

Allioideae is a subfamily of the Amaryllidaceae that includes a diverse group of bulbous, herbaceous perennials, many of which are prominent for their edible or ornamental value. The subfamily is distributed across temperate regions of the Northern Hemisphere and into Africa, with the best-known genera being Allium (onions, garlic, leeks, chives) and smaller lineages such as Tulbaghia (wild garlic from southern Africa) and Nectaroscordum (Mediterranean species). In many classifications, Allioideae is distinguished from other Amaryllidoideae by its bulbous habit, basal leaves, and characteristic inflorescences and flowers.

Morphology: Plants typically have tunicated bulbs. Leaves are usually basal, simple and linear. The inflorescence is often an umbel composed of many flowers. Each flower bears six petaloid perianth segments, six stamens, and an inferior ovary; the fruit is usually a capsule. A hallmark of many Allioideae is the emission of sulfur-containing compounds when tissues are crushed, giving an onion- or garlic-like scent.

Genera and uses: The most economically important genus is Allium, including edible crops such as onion, garlic, leek, chives, and shallot, as well as many ornamental forms. Other genera in the subfamily, such as Tulbaghia and Nectaroscordum, are used ornamentally or occur in the wild. Allioideae species are cultivated or found in gardens, landscapes, and natural habitats worldwide.