Kainulainen, K., B. Van EE, P. Antilahimena, H. Razafindraibe & P.E.Berry (2016). New species and species reports of Croton L. (Euphorbiaceae) from the eastern forest corridor of Madagascar. Candollea 71: 327–356. In English, English and French abstracts.
Six species of Croton from the Moramanga District of the Alaotra-Mangoro Region of eastern Madagascar (Toamasina Prov.) are newly described here, five of which occur in the Ambatovy mining concession. A seventh new species is described from the Ankerana Forest in the Atsinanana Region, some 80 km to the northeast of the town of Moramanga, which is one of the offset areas intended to mitigate the deforestation incurred by the Ambatovy mining project. Of the new species, Croton ferricretus Kainul., B.W. van Ee & P.E. Berry is the one most closely associated with the ultramafic soils where nickel and cobalt is being extracted. Although it is locally common, it is only known from the mine concession. Croton enigmaticus P.E. Berry & B.W. van Ee is considerably less common on the mine concession but is also known from two other sites. Croton droguetioides Kainul. & Radcl.-Sm. is known from Ambatovy and three other areas in the Alaotra-Mangoro Region, and Croton radiatus P.E. Berry & Kainul. is known only from forests on the Ambatovy mining concession and from the area of Zahamena National Park. Croton indrisilvae Kainul., B.W. van Ee & P.E. Berry is a small-leaved species known only from Analamazaotra National Park, and Croton ankeranae Kainul. is another small-leaved species known so far only from Ankerana. Croton plurispicatus P.E. Berry, Kainul. & B.W. van Ee is a distinctive small tree known mainly from the Lakato and Vohibe forests in the southern part of the Ankeniheny-Zahamena Corridor and one other location east of Analamazaotra. Croton hypochalibaeus Baill. is reinstated from synonymy and is now known from the Ambatovy area as well as in several forest remnants within the “tampoketsa” vegetation on the high central plateau of Madagascar, and in canyons of Isalo National Park. An additional species (Croton lasiopyrus Baill.) is identified from the Moramanga area for the first time, but is not currently known from Ambatovy. Amended descriptions are provided for both Croton hypochalibaeus and Croton lasiopyrus, and lectotypes are designated.