Black Nightshade
Solanum ptycanthum
Nightshade family (Solanaceae)

Description: This rather variable annual plant is native or adventive. It is about 1-3' tall and branches frequently. The stems are more or less hairy, but not prickly. The alternate leaves are up to 3" long and 2" across, with margins that are smooth, undulate, or bluntly dentate. They are usually broadly lanceolate, ovate, or deltoid, with a fine pubescence or scattered short hairs across the surface, especially on the undersides. The petioles are long and slender. The foliage of Black Nightshade is green or dark green. From the upper portion of the stems (rather than the leaf axils), there occasionally develops nodding umbels of white flowers from a short stalk (peduncle) about –1" long. Each umbel has 3-10 flowers. Both the peduncle of the umbel and the pedicels of the flowers are green and finely short-pubescent. 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 in shape.

The blooming period usually occurs during the summer or early fall. A single plant may produce flowers sporadically for about 2 months. Each flower is replaced by a small globoid berry about 6-8 mm. across. A berry has a smooth surface that is initially green, but it later becomes black at maturity. This berry is juicy and contains several flat 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. 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). It can be found in thickets, openings in degraded woodlands, rocky bluffs, cropland and pastures, gardens, vacant lots, areas along railroads, and waste areas. This plant is more common at sites with a history of disturbance and is rather weedy. Different authorities provide differing accounts of the origination of Black Nightshade: Some claim it is a native species with a worldwide distribution, while others believe that it is adventive from Europe, South America, or India.

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 fruits of Solanum spp. (nighshade species), including those of Black Nightshade, are eaten by various species of birds and mammals. This include 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 these plants 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 are 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. 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. Other scientific names for this species are Solanum nigrum and Solanum americanum.