This article is about the Solanum carolinense described by Carl Linnaeus. The S. carolinense described by Philip Miller

Philip Miller

Philip Miller FRS was a Scottish botanist.Miller was chief gardener at the Chelsea Physic Garden from 1722 until he was pressured to retire shortly before his death...

 is actually the S. houstonii of Martyn.

Carolina Horsenettle (Solanum carolinense) is not a true nettle

Nettle

Nettles constitute between 24 and 39 species of flowering plants of the genus Urtica in the family Urticaceae, with a cosmopolitan though mainly temperate distribution. They are mostly herbaceous perennial plants, but some are annual and a few are shrubby...

, but a member of the Solanaceae

Solanaceae

Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...

, or nightshade family. It is a perennial herbaceous plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

, native to southeastern United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 that has spread widely

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 throughout North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. This plant has hard spines along the stems that can penetrate the skin and break off, causing much pain.

"Horsenettle" is also written "horse nettle" or "horse-nettle", though USDA publications usually use the one-word form. Though there are other horsenettle nightshades, S. carolinense is the species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 most widely known simply as "the horsenettle". It is also known as Radical Weed or Sand Brier (or "briar"), while more ambiguous names are "bull nettle", "tread-softly" and "apple of Sodom

Apple of Sodom (disambiguation)

Apple of Sodom, Calotropis procera is a plant native to the Dead Sea and Sodom, Israel and other desert regions.Apple of Sodom may also refer to:Plants:* Solanum carolinense , native to North America...

". Names like Devil's Tomato and particularly "wild tomato" are better avoided, as the fruits of Carolina Horsenettle are poison

Poison

In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

ous and may kill a human who eats of them.

Description

Leaves are alternate, elliptic-oblong to oval, and each is irregularly lobed or coarsely toothed. Both surfaces are covered with fine hairs. The flower

Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s have five petals and are usually white or purple with yellow centers, though there is a blue variant that resembles the tomato

Tomato

The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...

 flower. The fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

s also resemble tomatoes. The immature fruit is dark green with light green stripes, turning yellow and wrinkled as it matures. Each fruit contains around 60 seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s. It flowers throughout the summer, from April to October.

Most parts of the plant are poisonous to varying degrees due to the presence of solanine

Solanine

Solanine is a glycoalkaloid poison found in species of the nightshade family , such as the potato . It can occur naturally in any part of the plant, including the leaves, fruit, and tubers. Solanine has fungicidal and pesticidal properties, and it is one of the plant's natural defenses...

 which is a toxic alkaloid and one of the plant's natural defenses, but while ingestion of the unripe fruit causes abdominal pain and may potentially cause circulatory and respiratory depression, the mature fruit is reputedly non-poisonous or less poisonous.

These plants can be found growing in pastures, roadsides, railroad margins, and in disturbed areas and waste ground. They grow to about 1 m tall, but are typically shorter, existing as subshrubs. They prefer sandy or loam

Loam

Loam is soil composed of sand, silt, and clay in relatively even concentration . Loam soils generally contain more nutrients and humus than sandy soils, have better infiltration and drainage than silty soils, and are easier to till than clay soils...

y soils.

Weed

Carolina horsenettle is considered a noxious weed in several US states. It can spread vegetatively by underground rhizome

Rhizome

In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...

s as well as by seed. It is resistant to many herbicide

Herbicide

Herbicides, also commonly known as weedkillers, are pesticides used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant...

s; in fact, herbicide use often selects for horsenettle by removing competing weeds. It is an especially despised weed by gardeners who hand-weed, as the spines tend to penetrate the skin and then break off when the plant is grasped. The deep root also makes it difficult to remove.

Beneficial weed

This plant is also seen as a beneficial weed

Beneficial weed

|thumb|right|Clover was once included in grass seed mixes, because of its great benefits to yard healthA beneficial weed is any of various plants not generally considered domesticated, but which nonetheless has some companion plant effect, or else is edible or somehow beneficial...

: the ripe fruit of this plant contains relatively little solanine, and is cooked by herb doctors to use as a sedative or antispasmodic. The plant also provides ground cover for beneficial predatory beetles, making it potentially beneficial in gardens.

Synonyms

Solanum pumilum (as described by Michel Félix Dunal

Michel Félix Dunal

Michel Felix Dunal was a French botanist. He was professor of botany in Montpellier, France. He held the chair of Medical Natural History from 1816 to 1819...

) was considered a variety hirsutum of the Carolina Horsenettle by D'Arcy and A. Gray. Several other varieties and form

Form (botany)

In botanical nomenclature, a form is one of the "secondary" taxonomic ranks, below that of variety, which in turn is below that of species; it is an infraspecific taxon...

s of S. carolinense are not considered taxonomically distinct nowadays:

• Solanum carolinense f. albiflorum (Kuntze) Benke
• Solanum carolinense var. albiflorum Kuntze
• Solanum carolinense var. floridanum (Dunal) Chapm.
• Solanum carolinense var. pohlianum Dunal

Finally, there are some other junior synonyms used for this plant:

• Solanum floridanum Raf.
• Solanum floridanum Shuttlew. ex Dunal (non Raf.: preoccupied)
• Solanum godfreyi Shinners
• Solanum pleei Dunal

External links

• Solanum carolinense information with several excellent pictures.
• Carolina Horse Nettle