Lactuca sativa L.

cultivated lettuce

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Cultivated lettuce (Lactuca sativa) has been around for thousands of years, but is apparently derived from prickly lettuce (Lactuca serriola), native to Eurasia and itself a common weed in North America. As a naturalized weed, cultivated lettuce is typically ephemeral, but it is found throughout most of the world. Lettuce is unquestionably the leafy vegetable most eaten by humans, and hundreds of cultivars exist.

Habitat

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

Characteristics

Habitat
terrestrial
New England state
  • Maine
  • Massachusetts
Leaf type
leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
  • the edge of the leaf blade has no teeth or lobes
  • the edge of the leaf blade has teeth
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
Ray flower color
  • blue to purple
  • yellow
Tuft or plume on fruit
at least a part of the plume is made up of fine bristles
Spines on plant
the plant has no spines
Leaf blade length
60–150 mm
Disk flower number
NA
Show All Characteristics
  • Flowers
    Bract color
    the bracts are not colored or tinged with pink, red or purple
    Bract cycle number
    there are two main cycles of bracts
    Bract inner side hairs
    the bracts are not hairy on their inner surfaces
    Bract outer side hair type
    the bracts are not hairy on their outer surface
    Bract outer side hairs
    the bracts are not hairy on their outer surfaces
    Bract shape
    • the main bracts are lanceolate (widest above the base, then taper narrowly towards the tip)
    • the main bracts are linear (long and very narrow)
    • the main bracts are of a different shape than the given options
    Bract spines
    the bracts have no spines
    Bract tip orientation
    • the bracts are pressed against the plant, or spreading out at the tips
    • the tips of the bracts curve outwards and downwards from the plant
    Bract tip shape
    • the tips of the bracts acute (have a sharp point)
    • the tips of the bracts are obtuse (have a blunt point)
    Bracts
    the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
    Disk flower color
    NA
    Disk flower lobe number
    NA
    Disk flower number
    NA
    Disk flower proportions
    NA
    Disk flower reproductive parts
    NA
    Disk flower shape
    NA
    Flower head number
    each flowering stem has four or more flower heads on it
    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 position
    some or all the flower heads are grouped in clusters of two or more
    Flower head profile
    • the disk is flat or nearly flat across the top
    • the disk is rounded across the top
    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
    6–15 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    • the inflorescence is flat-topped in profile
    • the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
    Number of bracts at flower head base
    5–13
    Ovary beak
    there is a 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 lines or ribs
    • there are four to six lines or ribs visible on the ovary
    • there are seven to nine ribs visible on the ovary
    Ovary profile
    in profile, the ovary is roughly egg-shaped, but widest above the middle
    Ovary surface
    the ovary surface is textured with tiny points, bumps or wrinkles
    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
    • 26-50
    • 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 a disk-shaped platform above the ovary
    Smaller bracts at base of bracts
    there is no smaller, outer cycle of bracts
    Style branch number
    NA
    Swelling at base of flower head
    the peduncles are not swollen, or only slightly
    Width of flower head base
    1–6 mm
  • Fruits or seeds
    Number of pappus parts
    11 or more
    Ovary beak length
    3–5 mm
    Ovary length in developed fruit
    6–9 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
    3.5–4 mm
    Seed hair tuft tips
    the pappus hairs are slender
    Seed hairs uniform
    all the pappus hairs are approximately the same length
    Seed tuft type
    the pappus is made of very fine hairs or bristles
    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
    Horizontal rooting stem
    there are no stolons
    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
    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
    • 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
    alternate: there is one leaf per node along the stem
    Leaf blade base
    the leaf has no petiole
    Leaf blade base shape
    the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
    Leaf blade edges
    • the edge of the leaf blade has no teeth or lobes
    • the edge of the leaf blade has teeth
    Leaf blade hairs
    NA
    Leaf blade length
    60–150 mm
    Leaf blade shape
    • the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    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)
    • the tip of the leaf blade is rounded, with no point
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip
    Leaf blade width
    120–250 mm
    Leaf disposition
    the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have no leaf stalks, but attach directly to the stem
    Leaf stalk length
    At least 0 mm
    Leaf type
    leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Specific leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets
  • Place
    Habitat
    terrestrial
    New England state
    • Maine
    • Massachusetts
    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 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

Not classified

New England Distribution and Conservation Status

Distribution

Connecticut
absent
Maine
present
Massachusetts
present
New Hampshire
absent
Rhode Island
absent
Vermont
present

Conservation Status

Exact status definitions can vary from state to state. For details, please check with your state.

Massachusetts
unranked (S-rank: SNR)

Native to North America?

No

Family

Asteraceae

Genus

Lactuca

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Information from Dichotomous Key of Flora Novae Angliae

4.  Lactuca sativa L. E

cultivated lettuce. MA, ME. Gardens, compost heaps, fields. Lactuca sativa is further characterized by a yellow corolla, white pappus, involucral bracts erect in fruit, and a flat cypsela body that has 5- to 9-nerved faces, the body terminated by an elongate, filiform beak.