Hairy Lettuce

Hairy Lettuce, Downy Lettuce

Lactuca hirsuta Muhl. ex Nutt.

Asteraceae (Sunflower Family)

Lactuca hirsuta, Hairy Lettuce, Downy Lettuce: (Bayer Code: not known US Code: not known)

  • A Missouri native biennial/summer annual/winter annual that grows 2-6 feet tall with round, smooth to hairy stems, often with purplish stripes or patches and hollow between the nodes
  • Stems usually unbranched until flowering
  • Basal leaves are 5-10 inches long and about 1/4 to 1/3 as wide, with deep lobes; lobes moderately toothed, margins sometimes with fine hairs; terminal leaf lobe slender
  • Leaves often slightly hairy on both sides, with fine hairs long underside of along midvein
  • Upper stem leaves become increasingly smaller and more narrow
  • Inflorescence often a large, open terminal panicle-like inflorescence but sometimes more like a compressed panicle or raceme; inflorescence has 25-100 heads; individual heads are about 1/4 diameter with 15-20 florets each; ray flowers are yellow to orangish, sometimes fading to bluish color with age
  • Involucre of bracts surrounding florets is urn-shaped, 13-20 mm long at start of flowering, lengthening to 15-22 mm long by fruiting
  • Flowers July-August
  • Fruit is small, oval, ridged achene, 3-5 mm long; numerous white hairs (pappus) 7-12 mm long are attached to a slender stalk at one end of the seed; stalk length is equal to or somewhat shorter than main fruit body
  • Has tan to light orange milky sap
  • Very similar to Lactuca canadensis, except L. hirsuta tends to have more hairs on leaves, and bract cluster (involucre) below individual heads is larger 13-20 mm at flowering/15-22 mm at maturity, compared to 8-10 mm long at flowering/10-14 mm long at maturity for L. canadensis
  • Native to Missouri, found in open woods, savannas, around ponds and along roadsides

(Updated September 8, 2023)

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