HS1176/HS1176: Biology and Management of American Black Nightshade (Solanum americanum P. Mill.) in Tomato, Pepper, Cucurbit, and Strawberry

Species Description

Class

Dicotyledonous plant

Family

Solanaceae

Other Common Names

American nightshade, black nightshade, common nightshade, garden nightshade, glossy nightshade, nightshade, small-flowered nightshade, Ink-berry

Life Span

Annual or short-lived perennial

Habitat

American black nightshade is commonly distributed in cultivated fields, pastures, gardens, lawns, footpaths, railroad tracks, and disturbed sites and waste areas in Florida. It is also very common in vegetable fields where it emerges in planting holes and in row middles.

Distribution

This species is widespread throughout the world and the exact native range is uncertain. It predominately occurs in tropic and sub-tropic regions and can be found throughout Florida.

Growth Habit

It is an herbaceous plant or small shrub with a predominantly upright growth habit that can reach a maximum height of 4 feet tall. Growth can be prostrate in some environments.

Seedling

Cotyledons are small and spoon-shaped with a prominent midrib on the underside of the cotyledon. They are green on both surfaces. The first leaf has a smooth to slightly wavy margin and often has a black to purple pigment on the underside of the leaf. Subsequent leaves will emerge in an alternate pattern.

Shoot

The stem is rough, erect, and highly branched, reaching up to 4 feet tall (Figure 2). Leaves are ovate (egg shaped) or lanceolate (shaped like a lance) with smooth, wavy, or slightly toothed or scalloped margins (Bryson and DeFelice 2009). Leaves have a petiole, are alternately arranged, and can be slightly to moderately pubescent (hairy) on the bottom (Figure 2).

Figure 2. 

Credit: Nathan S. Boyd, UF/IFAS

Roots

This species has a fibrous root system with a slender taproot.

Inflorescence

Flowers occur in an umbellate cluster (flower stalks of nearly equal length spring from a common center) of 4–12 flowers. The flower cluster emerges from the axils where the leaves join the stem. Flowers are bell shaped with five white, fused petals with five bright yellow anthers forming a cone around the pistil in the center of the flower (Figure 3).

Figure 3. 

Credit: Nathan S. Boyd, UF/IFAS

Fruit and Seeds

The fruits are berries that start out glossy green with white flecks and turn shiny black at maturity (Figure 3). The berries are borne in an umbel which consists of clusters of berries originating from one or nearly one point. There are approximately 50–110 seeds per berry. Immature berries and foliage are toxic to livestock.

Similar Species

This species is frequently confused with Eastern black nightshade and considered the same species by some authors. However, Eastern black nightshade (S. ptycanthum Dun.) may be more common in the midwestern United States whereas S. americanum appears to be more concentrated in the southern states.