Onion / Garlic Family

Franciscan Onion © DSchiel

Alliaceae (al-ee-AY-see-ee)

Iconic Features

  • Grow from bulbs
  • Narrow, basal leaves sheath the stem
  • Small flowers in umbels
  • Oniony smell

Description (Jepson)

  • Monocotyledons (monocots) – monocots are a major lineage of flowering, mostly herbaceous plants, generally characterized by
    • Single seed leaf (cotyledon)
    • Linear or oblong leaves with parallel venation
    • Flower parts in threes
    • Pollen grains with a single pore
    • Vascular bundles scattered in stem
    • Fibrous root system
  • Perennial herbs
  • Geophytes (plants with underground storage organs)
    • Grow from bulbs (short underground stems with fleshy leaves, e.g. culinary onion) or, occasionally, from rhizomes (horizontal underground stems)
  • Stem is usually a scape (leafless stem rising from ground level)
  • Leaves
    • Basal and sheathing the stem
    • Long and strap-like, with flat, tubular, or channeled faces
    • Usually wither before flowers appear
  • Flowers
    • Inflorescence (flower arrangement) is an open umbel (a spoke-like flower cluster with stalks radiating from a single point), with 2 bracts (modified leaves)
    • Small, bisexual, radially-symmetric flowers
      • 3 petals and 3 sepals (outer flower parts), in 2 separate whorls, similar in appearance and collectively called tepals
    • Ovary superior (above the attachment of other flower parts)
  • Fruit is a many-seeded capsule (a dry, multi-chambered fruit that splits open)


  • Approximately 800 species worldwide
    • Includes many species cultivated for food (e.g. garlic, chives, culinary onions) and ornamentals
  • Geophytes (e.g. plants growing from bulbs, corms, rhizomes, or enlarged taproots) are well adapted to survive fire, our Mediterranean climate’s long, dry summers, and extended droughts
    • Above-ground growth dies back after flowering, while underground the plant survives with stored water and nutrients
  • Plants have an onion-like odor and taste
    • Contain the chemical compound alliin, which converts to allyl sulfide compounds (allicin) when the plant is wounded (Simpson 2019)
  • Native people harvested many Onion-family species and other edible geophytes (Anderson 2005)
    • Bulbs were boiled, steamed, roasted, or baked in earthen ovens
    • Tender shoots and leaves of onions were eaten as fresh herbs
    • Plants were actively managed
      • Hardwood sticks were used for digging
      • Some plants were spared to allow future crops
      • Bulblets were dispersed and replanted
      • Areas were burned to decrease competition and recycle nutrients
  • Scientific name from the included genus Allium, from the Latin for “garlic”
  • Variously placed in other monocot families in the past, including the Lily family (Liliaceae), and, currently, the Amaryllis family (Amaryllidaceae)
  • Represented by 4 species at Edgewood

See General References

Specific References

Anderson, M.K. 2005. Tending the Wild. University of California, Berkeley.

Simpson, M.G. 2019. Plant Systematics (3rd ed.). Elsevier.

Browse Some Edgewood Plants in this Family