- Spirostachys Sond.
Three or four species are found in eastern tropical and southern Africa. Spirostachys africanus Sond. yields "jumping beans" (see Sapium P.Browne) (Watt & Breyer-Brandwijk 1962).
- Spirostachys africana Sond.
- [syns Excoecaria africana (Sond.) Müll.Arg., Sapium africanum (Sond.) Kuntze, Stillingia africana (Sond.) Baill.]
- African Mahogany, African Sandalwood, Cape Sandalwood, Sandalo Africano, Tomboti, Tambootie
The sap of the tree is reportedly acrid and capable of causing serious inflammation if applied to the eye or to skin abrasions. It may blister tender skin. The African is warned against the tambootie tree from earliest youth. The sawdust is very dangerous, irritating the eyes of sawyers, and may even cause blindness (Codd 1951, Pardy 1954, Watt & Breyer-Brandwijk 1962).
The wood is extremely handsome and makes attractive furniture. It is exported from East Africa as a substitute for sandalwood (Davy 1929). The wood is unsuitable for ox-yokes since it produces a "burning" effect on the animals' necks. Necklaces and charms, however, are made of it locally (Watt & Breyer-Brandwijk 1962).
Schmidt RJ & Olivier GW (1984 — unpublished observation) found extracts of the leaves and bark of this species to be non-irritant in the mouse ear irritancy assay.
- Stillingia sylvatica L.
- Queen's Root, Queen's Delight, Yaw Root
The juice of the green root is acrid; it inflames and swells the hands (Dispensatory 1884, White 1887) producing smarting and irritation (Piffard 1881).
Adolf & Hecker (1980) reported the presence of several tigliane and daphnane polyol esters in the roots of this species.
- Stillingia texana I.M.Johnst.
- [syn. Stillingia linearifolia Small]
- Queen's Delight
The milky sap is said to cause skin blisters, and is used to cure ringworm (von Reis Altschul 1973).
- Synadenium cupulare Wheeler
- [syn. Euphorbia cupularis Boiss.]
Application of the latex to the eye causes pain, severe inflammation, and even loss of the eye. On the skin, the latex produces an itchy rash, followed by blisters, sores, and desquamation. The latex gives off a highly irritant vapour; when collecting the plant, even if the specimen is held at arm's length, irritation of the eyelids, nostrils, and lips may be felt for several hours (Watt & Breyer-Brandwijk 1962).
- Synadenium grantii Hook.f.
- African Milk Bush
The plant is widely grown as an ornamental plant in the tropics and under glass in colder regions. The latex is undoubtedly extremely irritant (Watt & Breyer-Brandwijk 1962, Everist 1972) and was used by the Masai people of southern Africa as a blistering remedy for East Coast fever, the application being made over the swollen glands (Mettam 1932).
A gardener noted that the latex dripped from the cut stems onto the arms and forearms. She experienced no immediate discomfort but four hours later a burning sensation was felt and eight hours after exposure, streaky erythema and blisters appeared. Application of a drop of latex to the forearm of a volunteer was followed, after 6 hours, by intense irritation then by blistering (Rook 1965).
Thorold (1953) described the sudden development in 33 steers of large oedematous swellings between the brisket and near fore leg. Some also showed lesions between the hind limbs. No animal showed a lesion on the offside. Eight steers died. He believed that the lesions may have been caused maliciously using the latex of Synadenium grantii, a plant common in the nearby countryside.
Kinghorn (1980) identified 12-O-tigloyl-4-deoxyphorbol-13-isobutyrate as a major skin irritant principle in the latex of Synadenium grantii.
- Synadenium kirkii N.E.Br.
The plant is regarded as poisonous, the latex apparently being irritant (Watt & Breyer-Brandwijk 1962).
- Tragia L.
One hundred species are found in tropical and subtropical regions.
Pammel (1911), Wimmer (1926), Hutchinson & Dalziel (1928), Standley (1930), von Reis Altschul (1973), and Morton (1981) refer to the stinging hairs of:
- Tragia akwapimensis Prain
- Tragia angustifolia Benth.
- Tragia benthamii Baker
- Tragia chevalieri Beille
- Tragia laminularis Müll.Arg.
- Tragia miqueliana Müll.Arg.
- Tragia nepetaefolia Cav.
- Tragia polygonoides Prain
- Tragia pungens Müll.Arg.
- [syn. Jatropha pungens Forssk.]
- Tragia senegalensis Müll.Arg.
- Tragia spathulata Benth.
- Tragia tenuifolia Benth.
- Tragia urens L.
- Tragia urticaefolia Michx.
- Tragia wildemanii Beille
- Tragia yucatanensis Millsp.
This list could no doubt be expanded to include other species in the genus. Tragia preussii Pax, however, does not bear stinging hairs (Hutchinson & Dalziel 1928).
- Tragia adenanthera Baill.
Handling the plant results in immediate irritation of the skin (Watt & Breyer-Brandwijk 1962).
- Tragia affinis Müll.Arg.
This species is armed with stinging hairs (Anon 1912).
- Tragia bicolor Miq.
The stinging hairs which cover the entire plant have sharp silicaceous points which break off when touched and penetrate the skin. In addition to mechanical injury, sharp burning pain and inflammation occurs, like the effects produced by nettles (Urtica L. species, fam. Urticaceae) (Behl et al. 1966).
- Tragia cannabina L.f.
Rao & Sandararaj (1951) described the stinging hairs of this species. The plant has effects similar to those of Tragia bicolor Miq. (Behl et al. 1966). Hutchinson & Dalziel (1928) note that Tragia cannabina var. intermedia Prain is beset with stinging hairs.
- Tragia cissoides Müll.Arg.
Rao & Sandararaj (1951) noted that the stinging hairs of this species were morphologically dissimilar to those of Tragia cannabina L.f.
- Tragia cordifolia Vahl
The plant has a vesicant action (Pammel 1911).
- Tragia hispida Willd.
The plant has stinging hairs (von Reis Altschul 1973). The effects are similar to those of Tragia bicolor Miq. (Behl et al. 1966).
- Tragia rupestris Sond.
Rubbing the leaf on the forehead has been used in southern Africa for the relief of headache. Apparently, the application stings (Watt & Breyer-Brandwijk 1962).
- Tragia volubilis L.
- Vine Nettle, Twining Cowitch, Creeping Cowitch
Pammel (1911) lists the species as being irritant. The plant bears stinging hairs (Hutchinson & Dalziel 1928, Thurston & Lersten 1969) which sting severely (von Reis Altschul 1973). Cook & Collins (1903) noted that contact with the plant causes instant stinging and burning sensations, and may result in blisters.
- Vernicia fordii Airy Shaw
- [syn. Aleurites fordii Hemsl.]
- Tung Oil Tree, China Wood-Oil Tree, Kalo Nut
The tree is cultivated for tung oil contained in the seeds. The oil may be used in varnishes, and paints. Contact with tung oil can produce skin ulcers (Anon 1934), dermatitis of the groin and face, or generalised dermatitis (Tupholme 1939). According to Swaney (1938), finished tung oil varnishes are innocuous, but the vapour of heated tung oil can produce allergic contact dermatitis. A small proportion of workers handling the oil, and then probably only the heated oil, develop an allergic reaction to it (Watt & Breyer-Brandwijk 1962).
The liquid extruded by incision of the fruit exerts a local irritant effect on the skin (Carratalá 1936). Chewing a portion of the kernel and spitting it out produces irritation of the mouth and lips which continues for several hours (Watt & Breyer-Brandwijk 1962). The seeds and other plant parts are poisonous to man when ingested (Lewis & Elvin-Lewis 1977).
Chronic poisoning in animals from ingestion of Vernicia fordii produces, as part of the syndrome, cracking of the skin of the muzzle (Oakes & Butcher 1962).
The fruits have been found to contain esters of 16-hydroxyphorbol and 4-deoxy-16-hydroxyphorbol (Okuda et al. 1974, Okuda et al. 1975, Hirota et al. 1979).
- Victorinia regina Léon
- [syn. Jatropha regina Léon]
The plant, which is found in Cuba, contains an abundant irritant latex (von Reis & Lipp 1982).