''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 a genus in the family. Most spurges, such as ''Euphorbia paralias'', are herbs, but some, e ...

, and is one of some 100 species belonging to the genus ''Cnidoscolus'' (Gk. knidē-nettle, skōlos-thorn, 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 grc, μύρμηξ, mýrmēks ("ant") and ''khoreíā'' ("circular dance") is seed dispersal by ants, an ecologically significant ant–plant interaction with worldwide distribution. Most myrmeco ...

) attracted by the edible

elaiosome Elaiosomes ( grc, ἔλαιον ''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 elaio ...

. 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 (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de 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 b ...

Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the cou ...

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

and

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

. ''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 alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

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 Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. Adult butterflies have large ...

'', 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 ...

'' 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 inside o ...

. 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 (Lepidoptera) 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, bu ...

, 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

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