Endemic families of Madagascar. XV. A new critically endangered species of Schizolaena Thouars (Sarcolaenaceae) from northeastern Madagascar

Schizolaena impressa Ralainaorina, Birkinshaw & Lowry, sp. nov. (Sarcolaenaceae) is newly described. It is known only from the degraded and highly threatened forest of the Ambatobiribiry Massif and the less impacted Makirovana-Tsihomanaomby protected area, both in the SAVA Region of northeastern Madagascar. It resembles two other members of the genus that also occur in the humid forests of this region, S. masoalensis Lowry, G.E. Schatz, J.-F. Leroy & A.-E. Wolf and S. raymondii Lowry & Rabehevitra, but differs in several characters, in particular the deeply impressed secondary venation on the upper surface of its leaves, as well as the granular structure of the involucre that surrounds and completely encloses the fruit, even when ripe. A preliminary assessment of its conservation status according to IUCN Red List criteria indicates that S. impressa Ralainaorina, Birkinshaw & Lowry, sp. nov. is Critically Endangered [CR].