World Checklists - Euphorbiaceae - Royal Botanical Gardens, Kew

Euphorbia specimens - Paris (P)

Euphorbia specimens - Geneva (G)

African plants database

Plants of South Africa - Euphorbia

Euphorbia - Flora of Thailand

Euphorbia and Chamaesyce - Flora Iberica

International Euphorbia Society (IES)

Euphorbia page on Wikipedia

Volker Buddensiek's Succulent Euphorbia

Frank Vincentz's Succulent Euphorbia

Euphorbia for you - U4BA