Novelties in wild cassava (Manihot, Euphorbiaceae) from Brazil

Ongoing taxonomic studies on Manihot in Brazil based on field collections and herbarium consultations led us to describe a new species and to make other taxonomic and nomenclatural changes in the genus. Manihot minimiflora is described and illustrated as a new species from Tocantins state in northern Brazil. Along with M. sagittatopartita and M. acuminatissima, it has the smallest flowers in the genus. However, M. minimiflora can be easily differentiated from its closest relatives by its shrubby habit, androecium with eight stamens, 8-lobed staminate disc, differently shaped bracts and bracteoles of the staminate flowers, calyces of both sexes lacking any purplish or reddish pigmentation, and shorter seeds. A conservation assessment and data on the phenology, distribution, and morphology of the new species are provided. We also provide distribution maps, morphological characterization, and conservation status assessments for M. acuminatissima, M. longipetiolata, M. sagittatopartita, M. salicifolia, M. stricta, and M. weddelliana, as well as discuss their morphological relationships. Lectotypifications are provided for those six species and for two synonyms, M. riedeliana and M. mattogrossensis.