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(updated September 7, 2023) 

Woodland Lettuce, Tall Blue Lettuce, Florida Wild Lettuce

Lactuca floridana (L.) Gaertn.

Asteraceae (Sunflower Family)

▲▼first year rosette

▲▼first year rosette

▲first year rosette

▲elongating stem

▲▼leaves

▲▼approaching flowering size

▲▼mature, flowering plants

▲▼inflorescences

▲▼inflorescences

Lactuca floridana (L.) Gaertn., Woodland Lettuce, Tall Blue Lettuce, Florida Wild Lettuce: 

Bayer Code:  LACFL

US Code LAFL

·         A Missouri native biennial/summer annual/winter annual that grows 2-12 feet tall with round, smooth, purple-spotted green stems that are hollow between the nodes

·         Stems usually unbranched until flowering

·         Basal leaves are 4-18 inches long and about ¼ to 1/3 as wide, with moderate to deep lobes; lobes moderately toothed, margins sometimes with fine hairs; basal leaf terminal lobe is broadly triangular; similar Tall Lettuce has leaves that end in a narrow, tapering lobe

·         Leaves smooth to slightly hairy on undersides and along midvein; not spiny on midvein underneath, as with prickly lettuce

·         Upper stem leaves become increasingly smaller and more narrow

·         Large, open terminal inflorescence has 50-100 heads; individual heads are about ¼ diameter with 10-15 florets each; ray flowers are lavender to blue, occasionally white; bracts surrounding flowers often end in a purplish tip

·         Involucre of bracts surrounding florets is urn-shaped, 8-9 mm long at start of flowering, lengthening to 10-14 mm long by fruiting

·         Flowers June-October

·         Fruit is small, oval, ridged achene, 4-6 mm long; numerous white hairs (pappus) 5-7 mm long are attached to a slender stalk at one end of the seed; stalk length is less than ½ the length of the main fruit body

·         Has white milky sap

·         Native to Missouri; found in open woods, roadsides; not usually a serious weed problem

·         Similar species:

     o   Tall Blue Lettuce (Lactuca beinnis), is very similar to woodland lettuce, but is a more southern-occurring species and can only be definitively distinguished by the number of florets per head inflorescence:

       §  Lactuca floridana – has 10-15 florets per inflorescence

       §  Lactuca biennis – has 15-30 florets per inflorescence

     o   Perennial Blue Lettuce. (Lactuca tatarica), non-native creeping perennial with creeping roots that grows only 2-3 feet tall, often in open colonies; inflorescences have larger, showy, blue florets; more common in northern Midwest

     o   Wild Lettuce, Tall Lettuce (Lactuca canadensis),  is quite similar to Tall Blue Lettuce until flowering; wild lettuce has yellow ray flowers instead of blue to white, and tips of basal leaves end in long, tapered point; sap is also yellow, instead of white

     o   Willowleaf Lettuce (Lactuca saligna), a non-native species that appears similar to Prickly Lettuce, but has more linear to lanceolate, slightly lobed leaves with smooth margins, and only a few hairs, but no spines, along midvein on lower side of the leaf; leaves often more blue-green in color than other Lactuca spp.

     o   Prickly Lettuce (Lactuca serriola), a non-native species that can be readily identified by the row of stout hairs/prickles along midvein on lower side of the leaf and leaf margins, the lateral vertical orientation of stem leaves and yellow ray flowers; similar Willowleaf Lettuce has narrower leaves and no prickles along the lower leaf midvein