Two New Species of Madagascan Claoxylon (Euphorbiaceae, Acalyphoideae) and a Key to the Species of Madagascar and the Comoro Islands

Two new species of Madagascan Claoxylon A. Juss. are described, and a key to the resulting 12 species now considered to occur on Madagascar and the Comoro Islands is presented. Claoxylon ambrense McPherson is distinguished by its combination of exstipellate, oblanceolate, abruptly acuminate leaves bearing only unpaired hairs, and pistillate flowers with sepals 1–2 mm long and suborbicular disk glands. Claoxylon stylosum McPherson is characterized by its combination of large, ovate, densely pubescent, typically cordate leaves and pistillate flowers with long stylodia (3–3.5 mm), which are fused nearly half their total length. As well, C. medullosum Baill. is relegated to the synonymy of C. monoicum Baill.