Smodingium

African poison ivy
A sprig in the Pretoria N.B.G.
Compound leaf
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Sapindales
Family: Anacardiaceae
Genus: Smodingium
E.Mey. ex Sond. in Harv. & Sonder
Species: S. argutum
Binomial name
Smodingium argutum
E.Mey. ex Sond.

The African poison ivy (Smodingium argutum) is a southern African shrub or medium-sized tree in the Anacardiaceae, which has properties comparable to the American poison ivy,[1] as its sap contains heptadecyl catechols that are toxic to the skin.[2] An immuno-chemical reaction is suspected as in other toxic anacardiaceous species.[1] It is monotypic in the genus Smodingium,[1] and was discovered in Pondoland by J. F. Drège during an 1832 expedition with the zoologist Andrew Smith.[1]

Description

It resembles Rhus species in habit and foliage. It is very variable in size, sometimes a woody shrub barely 1–2 feet high, or otherwise a tree of up to 6m. During summer it produces small, creamy green flowers arranged in large sprays.[2] The Greek generic name, meaning "durated mark",[1] alludes to its hard, flattened seeds, which are fitted with papery wings.[2] The margins of the alternately arranged, trifoliolate leaves are toothed, as suggested by its specific name, argutum, which means "sharp".[1] The foliage assumes attractive autumn colours. When damaged the twigs exude a creamy, poisonous sap, which turns black when the catechols contained in it polymerize to a melanin.[1]

Range

It occurs along the Mpumalanga escarpment, the uplands of Swaziland, the KwaZulu-Natal midlands, Pondoland and Transkei, southern Lesotho and the southern Free State.[2]

References

  1. 1 2 3 4 5 6 7 Findlay, G.H. (31 August 1963). "Dermatitis of 'Poison Ivy' type from an indigenous South African plant - Smodingium argutum". S.A. Tydskrif vir Geneeskunde: 883–888.
  2. 1 2 3 4 Botha, C.J., Venter, E. "Smodingium argutum". (Paraclinical Sciences - Pharmacology & Toxicology). University of Pretoria. Retrieved 21 March 2013.
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