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• Asteraceae
• Asteraceae Group 1
• Sonchus
• Sonchus oleraceus

Sonchus oleraceus — common sow-thistle

Facts

Common sow-thistle is native to Europe and introduced worldwide, including across North America. Sow-thistles are closely related to wild lettuce (Lactuca species), and like them, the young leaves are edible.

Habitat

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

Characteristics

• Flowers

  Bases of bract appendages

  NA

  Bract cycle number

  there are three or more cycles of bracts

  Bract outer side hair type

  • the bracts are hairy on their outer surfaces, with hairs having glands (a swelling at the tip of the hair)
  • the bracts are hairy, with simple hairs on their outer surface
  • the bracts are not hairy on their outer surface

  Bract outer side hairs

  • the bracts are hairy on their outer surfaces
  • the bracts are not hairy on their outer surfaces

  Bract tip shape

  the tips of the bracts acute (have a sharp point)

  Bracts

  there are at least two distinct forms of bracts in different cycles

  Disk flower color

  NA

  Disk flower lobe number

  0

  Disk flower number

  0

  Disk flower proportions

  NA

  Disk flower reproductive parts

  NA

  Disk flower shape

  NA

  Flower head outer flowers

  at the outer edge of the flower head, each flower has a single enlarged lobe or strap

  Flower head platform

  the base has no bristles or papery scales

  Flower head platform surface

  NA

  Flower type in flower heads

  the flower head has ray flowers only, meaning all of the individual flowers of the flower head have a strap-shaped ray, which may or may not have teeth at the very tip of the ray

  Height of flower head base

  9–13 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  the inflorescence is flat-topped in profile

  Ovary beak

  there is no beak on the ovary

  Ovary cross-section

  the ovary is compressed (flattened)

  Ovary hair type

  the ovary has no hairs on it

  Ovary hairs

  the ovary has no hairs on it

  Ovary profile

  in profile, the ovary is lance-shaped, but widest above the middle

  Ovary surface

  the ovary surface is textured with tiny points, bumps or wrinkles

  Peduncle hair type

  the hairs on the peduncles have glands at their tips

  Peduncle hairs

  • the peduncles are hairy
  • the peduncles have no hairs

  Ray flower color

  • orange
  • yellow

  Ray flower reproductive parts

  the ray flowers have both carpels and stamens

  Ray flowers

  more than 50

  Reproductive system

  all the flowers on the plant contain both carpels and stamens

  Rim at top of ovary

  the central flowers have no disk-shaped platform above the ovary

  Scale tip

  NA

  Smaller bracts at base of bracts

  there is no smaller, outer cycle of bracts

  Style branch number

  there are no obvious branches on the style

  Swelling at base of flower head

  the peduncles are not swollen, or only slightly

  Width of flower head base

  6–14 mm

• Fruits or seeds

  Ovary beak length

  0 mm

  Ovary length in developed fruit

  2.5–3.5 mm

  Seed hair tuft color

  the pappus hairs are white or off-white

  Seed hair tuft details

  the pappus hairs are hooked or barbed

  Seed hair tuft length

  5–8 mm

  Seed hair tuft tips

  the pappus hairs are slender

  Seed hairs uniform

  there are two distinct lengths of pappus hairs

  Seed tuft scale number

  0

  Seed tuft type

  the pappus is made of very fine hairs or bristles

  Top of disk flower ovary

  NA

  Tuft or plume on fruit

  at least a part of the plume is made up of fine bristles

• Glands or sap

  Leaf blade glands

  the leaf blades have no glandular (translucent) dots or scales

  Sap

  the sap is milky and opaque, and may be white or colored

• Growth form

  Growth form

  the plant has one or more free-standing stems

  Plant lifespan

  the plant is annual, it lacks evidence of previous years' growth

  Spines on plant

  there are spines on the plant

  Underground organs

  there is a thickened taproot on the plant

• Leaves

  Hairs on underside of leaf blade

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

  Leaf arrangement

  alternate: there is one leaf per node along the stem

  Leaf blade base

  • the leaf has no petiole
  • the leaf has no petiole and at the base it clasps the stem, or goes all the way around the stem so the stem appears to pierce the leaf

  Leaf blade base shape

  the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)

  Leaf blade bloom

  there is a noticeable powdery or waxy bloom on the underside of the leaf

  Leaf blade edges

  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • the edge of the leaf blade has no teeth or lobes
  • the edge of the leaf blade has teeth

  Leaf blade length

  60–350 mm

  Leaf blade shape

  • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
  • the leaf blade is oblong (rectangular but with rounded ends)
  • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
  • the leaf blade is spatulate (spoon-shaped; narrow near the base, then suddenly widening to a rounded tip)

  Leaf blade surface colors

  there is no noticeable color variation on the upper surface of the leaf

  Leaf blade width

  10–150 mm

  Leaf disposition

  the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem

  Leaf spines

  there are spines along the leaf edges

  Leaf stalk

  the leaves have no leaf stalks, but attach directly to the stem

  Leaf stalk length

  0 mm

  Leaf tip extension

  NA

  Leaf type

  leaves are simple (lobed or unlobed but not separated into leaflets)

  Leaflet number

  0

  Specific leaf type

  the leaf has a row of two or more lobes on each side of the central axis

• Place

  Habitat

  terrestrial

  New England state

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont

  Specific habitat

  • man-made or disturbed habitats
  • meadows or fields

• Scent

  Plant odor

  the plant does not have much of an odor

• Stem, shoot, branch

  Flowering stem cross-section

  the flowering stem is circular, or with lots of small angles

  Leaves on stem

  there is at least one full leaf above the base of the flowering stem

  Stem bloom

  • the stem has a powdery or waxy film on it that can be rubbed away
  • there is no powdery or waxy film on the stem

  Stem internode hair direction

  NA

  Stem internode hair length

  0 mm

  Stem internode hair type

  the stem has no hairs between the nodes

  Stem internode hairs

  • the stem has hairs between the nodes
  • the stem has no hairs between the nodes

  Stem wings

  the stem does not have wings on it

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae