Lactuca floridana (Woodland Lettuce)
Also known as: | Florida Lettuce |
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Genus: | Lactuca |
Family: | Asteraceae (Aster) |
Life cycle: | annual, biennial |
Origin: | native |
Habitat: | part shade, shade; average moisture; deciduous woods |
Bloom season: | August - September |
Plant height: | 1 to 6 feet |
Wetland Indicator Status: | GP: FAC MW: FACU NCNE: FACU |
MN county distribution (click map to enlarge): | ![]() |
National distribution (click map to enlarge): | ![]() |
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Detailed Information
Flower:
Branching, open clusters of stalked flowers at the top of the plant and arising from upper leaf axils. Flowers are ¼ to ~½ inch across with 10 to 15 pale blue to lavender to whitish rays (petals).
The bracts (phyllaries) surrounding the base of a flower are variable in size, often dark purple or purple at the tips, hairless, overlapping, appressed, and the entire structure (involucre) forming a tube up to ½ inch (10 to 12 mm) long. Flower stalks are green to purple and hairless.
Leaves and stems:
Leaves are alternate and rather variable. Those near the base of the plant are up to 12 inches (30 cm) long and 8 inches (20 cm) wide, deeply divided with a large angular lobe at the tip and 1 to 3 pairs of smaller lateral lobes connected to a narrowly winged stalk.
Leaves become smaller with fewer lobes as they ascend the stem, the uppermost leaves frequently unlobed, triangular to lance-shaped on a winged stalk longer or shorter than the blade. Edges are coarsely toothed to nearly toothless; surfaces are hairless or sometimes sparsely hairy along major veins. Stems are single, erect, hairless, green to purple, and unbranched except in the flower clusters. Leaves, stems and roots exude a milky white sap when broken.
Fruit: 
Flower heads form seed heads about 1-inch in diameter with the phyllaries spreading out as seed matures. Seed is 4 to 6 mm long, brown, often mottled, flattened, generally elliptic, sometimes the tip extending to a stout beak up to 1 mm long. At the tip of the seed/beak is a tuft of white hairs to carry it off in the wind.
Notes:
Woodland Lettuce is an uncommon species that reaches the northern edge of its range in Minnesota. It is almost always found in woodlands here, but habitats are more varied the farther south you go. Only a handful of collections have been made since it was first recorded in Wright County in 1890; several additional locations are reported on iNaturalist. The DNR has been tracking it for possible inclusion on its rare species list.
Woodland Lettuce is recognized by the white sap, small light blue/lavender to whitish flowers, each with up to 15 rays, that are in a fairly open branching cluster; leaves frequently have a large triangular lobe at the tip and a narrowly winged stalk; seeds may have a very short (or absent) stout beak and have white hairs at the tip.
Most similar and reaching similar heights are Tall Blue Lettuce (L. biennis) and Canada Wild Lettuce (Lactuca canadensis), both of which can also be found in woods and may grow side-by-side with L. floridana. L. biennis has somewhat smaller flowers with 20 to 30+ rays in more crowded clusters (less open and diffuse) and has light brown to grayish hairs on seeds. L. canadensis has pale orange-brown sap, yellow to pinkish or orangish flowers, seeds are smaller, flattened oval-elliptic with white hairs at the tip of a thread-like beak half or more as long as the seed body, leaves are often clasping with basal lobes, and may have hairs only on the midrib.
My own personal observation is that L. floridana starts blooming at least two weeks later than the other two. Where these photos were taken, L. canadensis was in the same area, already had mature seed and was pretty much done flowering while L. floridana was still just budding.
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More photos
Woodland Lettuce plant
leaf underside is hairless to sparsely hairy along major veins
starting to flower in mid-August
close-up of seed heads
comparison of MN Lactuca species seed heads
comparison of MN Lactuca species seeds
Photos by K. Chayka taken in Scott County.
Comments
Have you seen this plant in Minnesota, or have any other comments about it?