''Cnidoscolus urens'' is a perennial, tropical American stinging herb of the family

Euphorbiaceae Euphorbiaceae (), the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of Euphorbia, the type genus of the family. Most spurges, such as ''Euphorbia paralias'', ar ...

, and is one of some 100 species belonging to the genus ''Cnidoscolus'' (from Gk. ''knidē'' "nettle", ''skōlos'' "thorn", and Latin ''urens'' "burning"). The plant is locally known as ''bull nettle'', ''spurge nettle'', ''bringamosa'' and ''mala mujer'' ("evil woman"). This species has an erect stem and is herbaceous when young, turning woody with age and from 50 to 150 centimeters tall. Leaves are lobed and large, while the white flowers occur in cymes, producing a spiny 3-seeded capsule with seeds rich in fats and proteins, resembling those of ''

Ricinus communis ''Ricinus communis'', the castor bean or castor oil plant, is a species of perennial flowering plant in the spurge family, Euphorbiaceae. It is the sole species in the monotypic genus, ''Ricinus'', and subtribe, Ricininae. The evolution of ca ...

''. Its carunculate seeds are usually dispersed by ants (

myrmecochory Myrmecochory ( (sometimes myrmechory); from ("ant") and ''khoreíā'' ("circular dance") is seed dispersal by ants, an ecologically significant Myrmecophily, ant–plant Biological interaction, interaction with worldwide distribution. Most ...

) attracted by the edible

elaiosome Elaiosomes ( ''élaion'' "oil" + ''sóma'' "body") are fleshy structures that are attached to the seeds of many plant species. The elaiosome is rich in lipids and proteins, and may be variously shaped. Many plants have elaiosomes that attract ...

. The entire plant is covered in stinging hairs, and has a native range covering Central and South America, being found in

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

El Salvador El Salvador, officially the Republic of El Salvador, is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south by the Pacific Ocean. El Salvador's capital and largest city is S ...

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...

Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

. ''Cnidoscolus urens'' is

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

and

self-compatible Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...

. Its male and female flowers appear superficially similar, but differ structurally. The principal pollinator during the dry season is a butterfly, ''

Eurema daira ''Eurema daira'', the fairy yellow, barred yellow or barred sulphur, is a butterfly of the family Pieridae. The species was first described by Jean-Baptiste Godart in 1819. It is found from Argentina north to the southern United States. Strays c ...

'', which does not discriminate between male and female flowers. Female flowers, making up only some 6% of the total, produce almost no nectar and appear to mimic males in order to receive attention from the pollen- and nectar-gathering insect. Male flowers usually function for only 1 day, while female flowers may remain functional for up to 7 days if unpollinated. ''Cnidoscolus'' was separated from the Linnaean genus ''

Jatropha ''Jatropha'' is a genus of flowering plants in the spurge family, Euphorbiaceae. The name is derived from the Greek words ἰατρός (''iatros''), meaning "physician", and τροφή (''trophe''), meaning "nutrition", hence the common name ph ...

'' on the basis of its stinging hairs or

trichomes Trichomes (; ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

, that consist of a multi-cellular pedestal and a single, elongate, hollow cell with a slightly swollen tip. On being touched, the brittle swollen tip breaks off at an oblique angle, the sharpened end readily penetrates the skin, and the cell contents are injected as if by a

hypodermic syringe A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the insid ...

. This poison leads to great irritation of the skin, a condition which may last several days. If part of the plant is eaten it causes swelling of the lips, flushing of the face, vomiting and even unconsciousness. Its latex is highly corrosive and may produce serious sores. A study in Costa Rica revealed that larvae of ''

Erinnyis ello ''Erinnyis ello'', the ello sphinx, is a moth of the family Sphingidae. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. It is distributed from Argentina through Central America to the United Stat ...

'', a moth of the family

Sphingidae The Sphingidae are a family of moths commonly called sphinx moths, also colloquially known as hawk moths, with many of their caterpillars known as hornworms. It includes about 1,450 species. It is best represented in the tropics, but species ar ...

, trim the stinging hairs from the leaf petiole then constrict the vessels supplying latex to the leaf, after which it can safely eat the leaf.''Butterflies of British Columbia'' - Jon Shepard, Crispin Guppy

References

External links

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{{Taxonbar, from=Q2980990 urens Plants described in 1753 Taxa named by Carl Linnaeus