Croton myriaster (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Medicinal
Timber

Croton myriaster Baker

Protologue: Journ. Bot. 20: 268 (1882).

Family: Euphorbiaceae

Croton myriaster is endemic to central Madagascar.

A decoction of the aerial parts is administered to children with epileptic attacks, and used as an inhalation to treat headache. The wood is used as firewood.

The bark contains traces of alkaloids, but none have been detected in the leaves.

Monoecious shrub or small tree up to 10 m tall; stem up to 20 cm in diameter; young twigs with short stellate hairs. Leaves alternate, simple, strongly scented; stipules small; petiole 1.5–2.5 cm long; blade ovate-lanceolate, 8–15 cm × 2.5–5.5 cm, base rounded, with 2 small, brown, sessile glands, apex acuminate, margins toothed, short-hairy, lower surface whitish. Inflorescence a terminal or axillary raceme, with male flowers at end and 2–3 female flowers at base. Flowers unisexual, regular, 5-merous, white to pale green or pale yellow; sepals small, brownish hairy, petals tiny; male flowers with short pedicel, stamens 12–16, free; female flower with pedicel enlarging in fruit to c. 2 cm long, ovary superior, 3-lobed, with pale brown hairs, 3-celled, styles 3, several times 2-fid at apex. Fruit a 3-lobed capsule c. 12 mm × 10 mm, hard, with glandular hairs, reddish brown, 3-seeded. Seeds ovoid, c. 7 mm long, grooved.

Croton comprises about 1200 species and occurs throughout the warmer regions of the world. It is best represented in the Americas; in continental Africa about 65 species occur and in Madagascar about 125. Almost 40 species from Madagascar are used in medicine, and several of them are morphologically close to Croton myriaster. Mattresses are filled with the strong smelling branches of Croton meridionalis Leandri, Croton salviformis Baill. and Croton tranomarensis Leandri to act as an insect repellent. The powder of the aerial parts of Croton meridionalis is added to bait as rat poison. A leaf infusion of Croton bemaranus Leandri is taken as a digestive. A leaf decoction of Croton goudotii Baill. is inhaled to treat malaria; a bark decoction is taken to treat chronic gonorrhoea. The latter is also used as a vapour bath and wash, and is taken orally to calm pain.

Croton myriaster occurs along humid forest margins, at 900–2200 m altitude.

There are no reports that Croton myriaster is threatened by genetic erosion.

Unless additional research reveals otherwise, Croton myriaster will remain of local importance only as a medicinal plant.

• Boiteau, P., Boiteau, M. & Allorge-Boiteau, L., 1999. Dictionnaire des noms malgaches de végétaux. 4 Volumes + Index des noms scientifiques avec leurs équivalents malgaches. Editions Alzieu, Grenoble, France.

• Govaerts, R., Frodin, D.G. & Radcliffe-Smith, A., 2000. World checklist and bibliography of Euphorbiaceae (with Pandaceae). Royal Botanic Gardens, Kew, Richmond, United Kingdom. 1620 pp.

• Leandri, J., 1939. Les Croton de Madagascar et des îles voisines. Annales de l’Institut Botanique-Géologique Colonial de Marseille 7(1). 100 pp.

• Missouri Botanical Garden, undated. VAST (VAScular Tropicos) nomenclatural database. [Internet] http://mobot.mobot.org/W3T/Search/vast.html. December 2006.

• Rasoanaivo, P., Petitjean, A. & Conan, J.Y., 1993. Toxic and poisonous plants of Madagascar: an ethnopharmacological survey. Fitoterapia 64: 117–129.

• Rasoanaivo, P., Petitjean, A., Ratsimamanga-Urverg, S. & Rakoto-Ratsimamanga, A., 1992. Medicinal plants used to treat malaria in Madagascar. Journal of Ethnopharmacology 37: 117–127.

• G.H. Schmelzer, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Schmelzer, G.H., 2007. Croton myriaster Baker. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 3 April 2025.

• See the Prota4U database.