4. Lactuca ludoviciana (Nutt.) Riddell (western wild lettuce)

Pl. 258 g, h; Map 1080

Plants biennial or occasionally short-lived perennials. Latex light tan. Stems (30–)50–150(–200) cm long, hollow between the nodes, glabrous, sometimes purple-streaked or purplish-tinged. Leaves well developed along the stem; the basal and lower stem leaves mostly 10–20(–30) cm long, usually sessile or nearly so, oblanceolate to oblong-ovate in outline, unlobed to deeply pinnately lobed, the margins also sharply toothed and somewhat prickly but glabrous, often with a pair of narrowly to more commonly broadly triangular basal lobes clasping the stem, the surfaces glabrous but the undersurface usually short-prickly along the midvein; the middle and upper stem leaves mostly lanceolate to linear, unlobed or with 1 or 2 pairs of narrowly pinnate lobes, the margins glabrous, usually with a pair of narrowly to broadly triangular basal lobes clasping the stem, the undersurface glabrous but often somewhat prickly along the midvein. Inflorescences mostly well-branched panicles with 50–100 or more heads. Involucre cylindrical, 13–15(–18) mm long at flowering, elongating to 18–20(–23) mm at fruiting, the bracts 17(–19). Florets 20–30(–55). Corollas yellow. Pappus (6–)8–10 mm long. Fruits with the body 4–6 mm long, 2–3 mm wide, dark brown to black, flattened, with prominent lateral wings and a conspicuous ridge on each face, tapered abruptly to a slender beak slightly shorter than to about as long as the body. 2n=34. June–August.

Uncommon, known only from two historical collections from Atchison and Greene Counties (western U.S. east to Indiana and Mississippi; Canada). Loess hill prairies and savannas.

The Atchison County specimen is atypical in having the leaves all unlobed, a condition that is comparatively uncommon elsewhere in the range of the species. The Greene County specimen was overlooked by Steyermark (1963).