A new species and putative hybrids of Manihot (Euphorbiaceae) from Brazil

This work describes and illustrates the new species Manihot reflexifolia, sp. nov. and compares its leaf anatomy to Manihot reniformis and probable hybrids between the two species. Manihot reflexifolia is also compared to Manihot jacobinensis from which it can be distinguished by its cylindrical petioles, elliptical to short lanceolate, reflexed leaf lobes and staminate flowers restricted to the terminal portion of the inflorescence (upper half), while M. jacobinensis has dorsiventrally flattened petioles, suborbicular to obovate leaf lobes, and staminate flowers along the entire inflorescence axis. The new species is restricted to rocky outcrops of the Chapada Diamantina in central Bahia State, Brazil. An identification key to Manihot species from rocky outcrops of Chapada Diamantina is provided. The leaf anatomy of M. reflexifolia, M. reniformis and the putative hybrids was analyzed using optical and scanning electron microscopy. Leaf anatomy was sufficient to characterize M. reflexifolia, M. reniformis and the putative hybrids, as well as to identify the first two wild taxa as potential progenitors of the hybrids (M. reflexifolia × M. reniformis). The most useful anatomical characteristics were the morphology of the petiole and midrib, bundle sheath extension, organization and quantity of vascular bundles, organization and composition of the mesophyll, and the presence of epidermal papillae.