Euphorbia alta Norton Euphorbia alta Norton, North Amer. Euphorbia [Preprint]: 24; pl. 24. 1899 sec. Steinmann 2025≡Tithymalus altus (Norton) Wooton & Standl., Contr. U.S. Natl. Herb. 16(4). 1913 syn. sec. Martínez-Gordillo & al. 2006