8. Silene latifolia Poir. (white campion, evening campion, white cockle)

S. pratensis (Rafn) Gren. & Godr.

S. latifolia ssp. alba (Mill.) Greuter & Burdet

Lychnis alba Mill.

Map 1487, Pl. 348 a, b

Plants annual or short-lived perennials, dioecious, with a sometimes woody taproot. Stems 30–100 cm long, erect, sometimes from a spreading base, branched, pubescent with stalked glands and also roughened with short, stiff, downward-angled hairs toward the base. Basal leaves usually withered at flowering, when present shorter than to about as long as the largest stem leaves, mostly long-petiolate. Stem leaves opposite, usually 6–12 pairs, sessile. Leaf blades 3–12 cm long, elliptic to lanceolate, tapered at the base, angled or short-tapered to a sharply pointed tip, the surfaces finely pubescent with sometimes somewhat tangled, nonglandular hairs. Flowers imperfect (either all staminate or all pistillate), in open terminal panicles or clusters, the stalks 0.5–4.0 cm long, those of the pistillate flowers usually longer than those of the staminate flowers, with stalked glands, the bracts paired and resembling small leaves, with green margins. Sepals 10–20 mm long, in pistillate flowers becoming enlarged to 30 mm at fruiting, the tube with 10 (staminate flowers) or 20 (pistillate flowers) parallel nerves, with a network of sparse to moderate, anastomosing, angled cross-nerves, tubular to slightly conical and not inflated at flowering, in pistillate flowers becoming ovoid and inflated as the fruit matures, the nerves green to reddish-tinged, pale to nearly translucent between the nerves, pubescent with a mixture of nonglandular hairs and stalked glands, the lobes ovate to narrowly triangular, green to purplish, angled or short-tapered to a sharply pointed tip, the margins green. Petals 5, 24–32 mm long, the expanded portion 8–12 mm long, entire to 2-lobed at the tip, white, with a pair of small appendages on the upper surface at the base of the expanded portion. Styles (4)5. Fruits 11–18 mm long, dehiscing apically by (8)10 teeth, with a stalklike base 0.8–1.5 mm long. Seeds 1.0–1.3(–1.5) mm wide, kidney-shaped and plump, the surface coarsely tuberculate, dark grayish brown to dark grayish black. 2n=24. May–September.

Introduced, scattered nearly throughout the state (native of Europe, Asia, Africa; introduced nearly throughout the U.S. [including Alaska] except some southeastern states, Oklahoma, and Texas). Pastures, fallow fields, old fields, old homesites, ditches, railroads, roadsides, and open, disturbed areas.

First collected in Jackson County in 1915, S. latifolia sometimes has been confused with S. noctiflora, a plant with perfect flowers, creamy white or pinkish petals, and 3 styles. The proper name for this taxon has been the subject of intense nomenclatural research (McNeill and Prentice, 1981; Greuter and Burdet, 1982). For a discussion of putative hybrids with S. dioica, see the treatment of that species.

The attractive flowers of S. latifolia open in the early evening and are sweetly fragrant. Dean (1963) studied more than 50,000 individual flowers of this species from Iowa and Minnesota populations. She found that although S. latifolia pistillate flowers usually had 5 or less often 4 styles, about 1 percent of her samples had 6–8, 0–3, or 9–13 styles. Morton (2005c) observed that many North American specimens of S. latifolia appear to be morphologically intermediate between the two most common subspecies recognized by some European authors, ssp. latifolia and ssp. alba (Mill.) Greuter & Burdet and thus chose not to formally recognize these taxa. His treatment is followed here.