Lactuca serriola — prickly lettuce

Characteristics

• Flowers

  Bases of bract appendages

  NA

  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 head shape

  the sides of the flower head are roughly parallel, like a cylinder

  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

  9–12 mm

  Inflorescence branching (Solidago)

  NA

  Inflorescence shape

  the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others

  Ovary beak

  there is a beak on the ovary

  Ovary cross-section

  the ovary is compressed (flattened)

  Ovary hairs

  the ovary has hairs on it

  Ovary profile

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

  Ray flower color

  • blue to purple
  • yellow

  Ray flower reproductive parts

  the ray flowers have both carpels and stamens

  Ray flowers

  • 11-15
  • 16-25

  Reproductive system

  all the flowers on the plant contain both carpels and stamens

  Rim at top of ovary

  the central flowers have a disk-shaped platform above the ovary

  Scale tip

  NA

  Smaller bracts at base of bracts

  there is a cycle of much smaller bracts outside the cycle of larger and longer bracts

  Style branch number

  there are no obvious branches on the style

  Width of flower head base

  3–5 mm

• Fruits or seeds

  Ovary beak length

  2.5–4 mm

  Ovary length in developed fruit

  2.5–3.5 mm

  Ovary width in developed fruit

  0.7–0.9 mm

  Seed hair tuft color

  the pappus hairs are white or off-white

  Seed hair tuft length

  3–5 mm

  Seed hair tuft tips

  the pappus hairs are slender

  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
  • the plant is biennial, it appears as either first year (non-reproductive) plants or second year plants with flowers or fruit

  Spines on plant

  • the plant has no spines
  • 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 fuzzy or hairy

  Leaf arrangement

  alternate: there is one leaf per node along the stem

  Leaf blade base

  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

  • the underside of the leaf has no noticeable 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 teeth

  Leaf blade length

  60–150 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)

  Leaf blade surface colors

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

  Leaf blade tip

  • the tip of the leaf blade is acute (sharply pointed)
  • the tip of the leaf blade is obtuse (bluntly pointed)

  Leaf blade width

  15–100 mm

  Leaf disposition

  • the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
  • the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves

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

• 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

  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 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)

In New England

From Flora Novae Angliae dichotomous key