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Published In: De Fructibus et Seminibus Plantarum. . . . 2(3): 362. 1791. (Fruct. Sem. 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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2. Lactuca floridana (L.) Gaertn. (Florida lettuce, woodland lettuce)

Pl. 258 c, d; Map 1078

Plants annual or biennial. Latex plants white. Stems 40–250(–350) cm long, hollow between the nodes, glabrous, often purple-spotted. Leaves well developed along the stems, extremely variable; the basal and lower stem leaves mostly 7–35(–45) cm long, sessile or more commonly with a winged petiole, narrowly ovate, ovate, or obovate in outline, variously toothed and/or deeply pinnately lobed, the margins sometimes minutely hairy, sometimes with a pair of narrowly triangular basal lobes clasping the stem, the undersurface sometimes short-hairy, especially along the midvein; the middle and upper stem leaves mostly lanceolate to ovate, or obovate, pinnately lobed to nearly entire, the margins usually glabrous, sometimes with a pair of narrowly to broadly triangular basal lobes clasping the stem, the undersurface glabrous. Inflorescences mostly well-branched panicles with 50–100 or more heads. Involucre cylindrical or urn-shaped, 8–9 mm long at flowering, elongating to 10–14 mm at fruiting, the bracts 14–17. Florets 10–17(–25). Corollas lavender to purplish blue or blue, rarely white. Pappus 5–7 mm long. Fruits with the body 4–6 mm long, 1.5–2.0 mm wide, brown to dark brown, often mottled, flattened, with somewhat thickened margins and 4 or 5 nerves or ridges on each face, narrowed or tapered abruptly, beakless or with a short, stout beak much less than 1/2 as long as the body. 2n=34. July–October.

Common throughout the state (eastern U.S. west to South Dakota and Texas; Canada). Banks of streams and rivers, bottomland forests, mesic upland forests, savannas, sand savannas, glades, bases of bluffs, and margins of ponds and lakes; also railroads, roadsides, and open, disturbed areas.

As in L. canadensis, a number of infraspecific variants have been described documenting different leaf morphologies. Of these, f. villosa (Jacq.) Cronquist, with unlobed, toothed leaves, occurs fairly commonly in Missouri. White-flowered plants have been called f. leucantha Fernald.

 


 

 
 
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