Black Nightshade
Solanum ptycanthum
Nightshade family (Solanaceae)

Description: This annual plant is about 1-3' tall, branching frequently above. The stems are glabrous to slightly short-hairy, but not prickly. The alternate leaves are up to 3" long and 2" across; they are usually broadly lanceolate, ovate, oval, or oval-deltate in shape, while their margins are smooth, undulate, or bluntly dentate. The leaf surfaces are medium green to dark green and glabrous to slightly short-hairy; when hairs are present, they are usually more common along the leaf undersides. The petioles are relatively long and partially winged toward their blades. Solitary umbels of nodding white flowers (rarely violet-purple flowers) occasionally develop from the axils of the middle to upper leaves. Each umbel has 3-10 flowers. The peduncles of the umbels are about " long, while the pedicels of the flowers are about one-half of this length. Both the peduncles and pedicels are green, slender, and glabrous to slightly short-hairy. Each flower is about 6-8 mm. across, consisting of a star-like white corolla with 5 tapering lobes that curve backward. Projecting from the center of the corolla, there are 5 stamens with large yellow anthers that are appressed together against the pistil. The green sepals are connected to each other at the base of the flower; they are lanceolate-oblong in shape.

The blooming period usually occurs during the summer or early fall. A single plant may produce flowers sporadically for about 2 months. The flowers are replaced by small globoid berries about 6-8 mm. across. The outer surface of the berries is initially green and smooth, but it later becomes black and shiny. Mature berries are juicy, bland to sweet, and sometimes slightly bitter; each berry contains numerous flattened seeds that are yellow or brown. The root system consists of a slender taproot that branches frequently. This plant spreads by reseeding itself.

Cultivation: Black Nightshade is an adaptable plant that flourishes in full or partial sun, moist to mesic situations, and almost any kind of soil, especially fertile loam with abundant nitrogen. The size of a plant depends heavily on moisture levels and soil fertility.

Range & Habitat: This common plant has been observed in most counties of Illinois (see Distribution Map), where it is native. Habitats include thickets, openings in degraded woodlands, thinly wooded bluffs, cropland and pastures, gardens, vacant lots, areas along railroads, fence rows, back alleys in urban areas, and waste areas. This plant is more common at sites with a history of disturbance and it is rather weedy. Most authorities consider Solanum ptycanthum (Black Nightshade) to be distinct from the European Solanum nigrum (Deadly Nightshade).

Faunal Associations: Bumblebees collect pollen from the flowers (Robertson, 1929). Nectar is unavailable as a floral reward. Several species of insects feed destructively on Black Nightshade, especially the larvae and adults of leaf beetles (Chrysomelidae). This includes such species as Acallepitrix nitens (a leaf beetle), Epitrix cucumeris (American Potato Flea Beetle), Epitrix fuscula (Eggplant Flea Beetle), Epitrix hirtipennis (Tobacco Flea Beetle), Lema daturaphila (Three-lined Potato Beetle), Lema trivittata (Three-lined Lema Beetle), Leptinotarsa decemlineata (Colorado Potato Beetle), Plagiometriona clavata (Clavate Tortoise Beetle), Psylliodes affinis (European Potato Flea Beetle), larvae of the moths Heliothis subflexus (Subflexus Straw) and Manduca sexta (Tobacco Hornworm), and maggots of Liriomyza trifolii (American Serpentine Leafminer); see Clark et al. (2004), Covell (1984/2005), Wagner (2005), and Spencer & Steyskal (1986). The mature fruits of Solanum spp. (nightshade species), including those of Black Nightshade, are eaten by various species of birds and mammals. This includes such birds as the Ruffed Grouse, Wild Turkey, Eastern Meadowlark, Gray Catbird, and Swamp Sparrow; the Bird Table has a more complete list of such birds. Mammals that eat the fruits of these plants include the Raccoon, Striped Skunk, White-tailed Deer, and small rodents; see Martin et al. (1951/1961), Myers et al. (2004), and Hamilton (1941). Because the seeds in these fruits are able to pass through the digestive tracts of many animals and remain viable, they are distributed across considerable distances, introducing this plant into new areas. The foliage of Black Nightshade is toxic and bitter, therefore it is usually avoided by mammalian herbivores (Georgia, 1913).

Photographic Location: On the grounds of the webmaster's apartment complex in Urbana, Illinois.

Comments: The berries of Black Nightshade (Solanum ptycanthum) are probably edible to humans, if they are fully ripe and eaten in small quantities. Green berries contain the toxic alkaloid, solanum, like the foliage. There are several Solanum spp. that occur in Illinois. They fall into two groups: Those species with sharp bristles or spines, and those species without sharp bristles or spines. Black Nightshade falls into the latter group. In Illinois, the Solanum spp. in this latter group can be distinguished from each other by the appearance of their leaves: Black Nightshade has broader leaves that are without deep lobes along their sides, and they lack conspicuous silvery hairs. Some Solanum spp. have mature berries that are either green or yellow, but the mature berries of Black Nightshade are always black. The berries of Black Nightshade are slightly smaller in size and more shiny than those of Deadly Nightshade (Solanum nigrum), and its seeds are slightly smaller in size than those of the latter. Black Nightshade produces true umbels of flowers (all pedicels originating from the same location), while Deadly Nightshade produces pseudo-umbels of flowers (the pedicels originating from slightly different locations). This latter species has not been recorded from Illinois. A scientific synonym of Black Nightshade is Solanum americanum.

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