1. Lapsana communis L. (nipplewort)

Pl. 260 a–c; Map 1084

Plants annual, with shallow, fibrous roots. Latex white. Stems 1 or few, 15–80 cm long, erect or ascending, unbranched or few-branched below the midpoint, finely longitudinally ridged, sparsely to moderately pubescent with slender, multicellular, spreading hairs, these often gland-tipped, especially toward the stem tip, occasionally nearly glabrous with age. Leaves basal and alternate, sessile or with a short to long, winged petiole. Leaf blades 1–15 cm long, those of the basal and lower stem leaves obovate to oblanceolate, with a large, ovate terminal lobe abruptly tapered to a narrower, pinnate series of lobes, these sharply triangular with mostly broadly rounded sinuses; those of the upper (and sometimes also median) stem leaves mostly unlobed, entire or with few to several broad, shallow, spreading teeth, both surfaces sparsely to moderately pubescent with short, white, more or less spreading, nonglandular hairs. Venation of 1 main vein and a complex network of anastomosing secondary and tertiary veins. Inflorescences terminal panicles or occasionally loose terminal clusters. Heads appearing mostly long-stalked. Involucre 5–10 mm long, cup-shaped, the bracts in 2 series, glabrous or inconspicuously cobwebby- or glandular-hairy along the margins, those of the outer series 4 or 5, 0.5–2.5 mm long, ovate to narrowly triangular, green; those of the inner series 8–10, narrowly oblong, usually becoming keeled as the fruits mature, sometimes becoming somewhat hardened and pale yellow at maturity. Receptacle naked. Ligulate florets 8–15. Corollas 7–10 mm long, lemon yellow to yellow. Pappus absent. Fruits 3–5 mm long (those of the outer florets longer than those of the inner ones), narrowly oblong in outline, often slightly flattened, with numerous fine ribs, somewhat curved, slightly tapered to a more or less truncate tip, not beaked, the surface otherwise smooth, glabrous, shiny, light brown to yellowish brown. 2n=12, 14, 16. June–September.

Introduced, uncommon and sporadic in the Ozark and Ozark Border Divisions (native of Europe, Asia, introduced nearly throughout the U.S. [including Alaska], Canada, Greenland). Banks of streams and rivers; also roadsides and open, disturbed areas.

In its native range, this species occasionally is eaten raw or cooked. Some European manuals divide L. communis into a number of subspecies based on minor, mostly quantitative variations. Missouri material keys to ssp. communis in these treatments.