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• Alliaceae
• Allium
• Allium cepa

Allium cepa — garden onion

Facts

Garden onion is cultivated worldwide. Although it there is no known wild progenitor, the nearest wild relative is Allium oschanini, a species from central Asia. There are many cultivars of onion, with a wide range of morphologies, including some with bulbils in the inflorescence. Garden onion may escape within areas of cultivation or agriculture, and occurs sporadically across North America, including New England.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields

Characteristics

• Clonal plantlets

  Axillary bulblets

  there are no bulblets being produced in axils

• Flowers

  Anther attachment

  the anther is attached by its base to the filament

  Anther color

  the anthers show no hint of a pink, reddish or purplish tint

  Bulblets replace flowers

  there are no bulblets where the flowers are located

  Carpels fused

  the carpels are fused (the number of carpels equals the number of locules)

  Filament surface

  the filament surface has no hairs or scales on it

  Flower bracts

  there are bracts associated with the flower

  Flower number

  Up to 500

  Flower orientation

  the flowers point upward or spread or curve outward

  Flower petal color

  • pink to red
  • white

  Flower petal length

  3–4.5 mm

  Flower shape

  • the flower has an urn-shaped corolla (constricted at the opening)
  • the flower is bell-shaped

  Flower symmetry

  there are two or more ways to evenly divide the flower (the flower is radially symmetrical)

  Flowering stem width

  3–20 mm

  Form of style

  the style is knob-like at the tip, and unbranched

  Fringed petal edges

  the petals are not fringed

  Hairs on flower stalk

  the flower stalk has no hairs on it

  Inflorescence hair glands

  the axis of the inflorescence has no hairs on it

  Inflorescence length

  300–1000 mm

  Inflorescence type

  the inflorescence is an umbel (with an axis so short it appears the flowers all originate from the same point)

  Inflorescence width

  3–20 mm

  Length of flower stalk

  10–50 mm

  Length of peduncle

  Up to 1000 mm

  Marks on petals

  there are no noticeable marks on the petals

  Nectar spur

  the flower has no nectar spurs

  Number of carpels

  3

  Number of pistils

  1

  Number of sepals and/or petals

  there are six petals, sepals or tepals in the flower

  Number of styles

  1

  Ovary position

  the ovary is above the point of petal and/or sepal attachment

  Petal and sepal arrangement

  the flower includes two cycles of petal- or sepal-like structures

  Petal appearance

  the petals are thin and delicate, and pigmented (colored other than green or brown)

  Petal base

  the petal narrows gradually or does not narrow at the base

  Petal fusion

  the perianth parts are separate

  Petal hairs on inner/upper surface

  there are no hairs on the inner/upper petal surface

  Sepal appearance

  the sepals resemble petals in color and texture

  Sepal length

  3–4.5 mm

  Sepal orientation

  • the sepals are pressed against the plant, or jutting stiffly upward
  • the sepals are slightly curved outwards from the plant

  Sepals fused only to sepals

  the sepals are separate from one another

  Spathe

  • the plant does not have a spathe
  • the plant has a spathe surrounding the flower spike

  Spathe form

  • NA
  • the spathe just wraps around the base of the spike of flowers

  Stamen number

  6

  Stamen position relative to petals

  NA

  Stamen types

  the stamens within a cycle are distinctly of two types

  Stamens fused

  the stamens are not fused to one another

  Stamens fused outwards

  the stamens are fused to the petals or tepals at or near their bases

  Style petal-like

  the style is not broad and flattened like a petal

  Tepals

  the petals and sepals are similar in size and color

• Fruits or seeds

  Berry color

  NA

  Capsule ridges

  there are no ribs or wings on the capsule

  Fruit compartments

  there are three locules in the fruit

  Fruit cross-section

  the fruit is round in cross-section

  Fruit length

  Up to 5 mm

  Fruit stalk orientation

  the fruits point upward or spread or curve outward

  Fruit type (general)

  the fruit is dry and splits open when ripe

  Fruit type (specific)

  the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)

  Other markings on berry

  NA

• Glands or sap

  Sap

  the sap is clear and watery

• Growth form

  Lifespan

  the plant lives more than two years

  Root septa

  the roots do not have transverse septa

  Underground organs

  the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms

• Leaves

  Hairs on underside of leaf blade

  the underside of the leaf is not hairy, or has very few hairs

  Hairs on upper side of leaf blade

  the upper side of the leaf is not hairy, or has very few hairs

  Leaf arrangement

  basal: the leaves are growing only at the base of the plant

  Leaf blade basal lobes

  the leaf blades do not have basal lobes

  Leaf blade base

  the leaf has no stalk

  Leaf blade base shape

  the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow

  Leaf blade bloom

  the underside of the leaf blade has no noticeable waxy or powdery bloom

  Leaf blade cross-section

  the leaf blade is round or semicircular

  Leaf blade faces

  both surfaces of the leaf blade are exposed

  Leaf blade form

  Fully-formed (i.e., expanded), +/- green leaf blades are found somewhere on the plant

  Leaf blade length

  100–500 mm

  Leaf blade orientation

  the upper surface of the leaf blade faces the stem of the plant

  Leaf blade shape

  the leaf blade is linear (very narrow with more or less parallel sides)

  Leaf blade surface colors

  the upper side of the leaf blade is relatively uniform in color

  Leaf blade tip

  • the tip of the leaf blade is acuminate (tapers to a long, thin point)
  • the tip of the leaf blade is acute (sharply pointed)

  Leaf blade veins

  the lateral veins are parallel or slightly arched in the direction of the tip

  Leaf blade width

  3–20 mm

  Leaf stalk length

  0 mm

  Leaf type

  the leaves are simple (i.e., lobed or unlobed but not separated into leaflets

  Leaflet number

  0

  Stipule twining

  NA

  Stipules

  there are no stipules on this plant

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields

• Scent

  Plant odor

  the leaves smell of onion or garlic

• Stem, shoot, branch

  Flowering stem growth form

  the flowering stem is held upright

  Flowering stem interior

  • the flowering stem is hollow
  • the flowering stem is solid

  Flowering stem leaves

  there are no true leaves on the flowering stem

Wetland status

Not classified

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae