Revision of the Malesian species of Micrococca (Euphorbiaceae)

Micrococca is a rare genus represented in the Malesian region by only three species. Micrococca mercurialis (L.) Benth. is widespread, but in Malesia it is found only in Peninsular Malaysia. Micrococca malaccensis Airy Shaw and M. johorica Airy Shaw are both endemic to Johore. Micrococca can be distinguished from its close allies, Erythrococca and Claoxylon, by its interrupted racemes (with long internodes), pistillate flowers with elongated (strap-like) disc lobes, and a deeply 3-lobed, thinly crustaceous capsule dehiscing both septicidally and loculicidally. Micrococca mercurialis is a small-leaved shrub, while the other two species are trees with much larger leaves. Micrococca johorica has glands on the leaf bases, narrow leaves, and short inflorescences, whereas M. malaccensis lacks glands on the leaf bases, has wider leaves, and longer inflorescences.