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Published In: The Genera of North American Plants 2: 124. 1818. (14 Jul 1818) (Gen. N. Amer. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native


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3. Lactuca hirsuta Muhl. ex Nutt. (downy lettuce, hairy lettuce)

Pl. 258 e, f; Map 1079

Plants usually biennial. Latex light tan to pale orange. Stems 30–200 cm long, hollow between the nodes, glabrous to densely pubescent with relatively long, curled hairs, often purple-streaked or purplish-tinged. Leaves best-developed toward the stem base, reduced in size and often unlobed above the stem midpoint, the basal and lower stem leaves mostly 10–20 cm long, with a winged petiole, ovate or obovate in outline, deeply pinnately lobed and sharply toothed, the margins sparsely hairy, sometimes with a pair of narrowly to broadly triangular basal lobes clasping the stem, the surfaces usually short-hairy, less commonly only sparsely hairy on the undersurface midvein. Inflorescences mostly well-branched panicles with (15–)25–100 heads, occasionally appearing nearly racemose. Involucre cylindrical or urn-shaped, 13–20 mm long at flowering, elongating to 15–22 mm at fruiting, the bracts 17(–19). Florets (12–)15–20(–22). Corollas yellow to orangish yellow, sometimes turning blue with age or upon drying. Pappus 7–10(–12) mm long. Fruits with the body 3–5 mm long, 2.0–2.5 mm wide, dark brown to black, flattened, with prominent lateral wings and a conspicuous ridge on each face, tapered abruptly to a slender beak somewhat shorter than to about as long as the body. 2n=34. June–September.

Uncommon in the Ozark and Ozark Border Divisions (eastern U.S. west to Illinois and Texas; Canada). Mesic to dry upland forests, savannas, sand savannas, and margins of sinkhole ponds; also roadsides.

This species is similar to L. canadensis but tends to be hairier and to have larger involucres and fruits. It also has the leaves more basally disposed. Several infraspecific taxa have been described based on the extent of hairiness and the colors of florets. Two phases that occur in the state are var. hirsuta, with stems and both sides of the leaves hairy, and var. sanguinea (Bigelow) Fernald, with stems glabrous or nearly so and leaves glabrous or sparsely hairy along the midvein on the undersurface. These variations seem unworthy of formal taxonomic recognition, and intermediates exist.



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