Manihot allemii sp. nov. (Euphorbiaceae s.s.) with entire and unlobed leaves from northern Brazil, with notes about foliar anatomy

Abstract

Manihot allemii M. J. Silva is described and illustrated as a new species, and its morphological affinities and conservation status is discussed. It is most similar to M. salicifolia Pohl in having a subshrubby and erect habit and in the general aspect of its unlobed leaves, but differs from it in having leaves that are conspicuously petiolate, an inflorescence that is a congested spike-like thyrse, entire and diminute bracts and bracteoles subtending flowers of both sexes, pistillate calyx that is deeply lobed with oblong lobes, and staminate flowers with 8 or 10 stamens. Both species belong to a group of 14 species recognized by their possession of entire and unlobed leaves, which are the subject of taxonomic studies by the second author. Some notes on the leaf anatomy of species of Manihot that have entire and unlobed leaves are also presented.

Comparative leaf anatomy of wild Manihot Mill. species (Euphorbiaceae) from Chapada Diamantina, Bahia, Brazil

“…Cunha Neto et al (), reinforcing studies of the epidermal surface carried out by Allem (), noted that the presence of papillae is valuable when distinguishing Manihot species, however, in the present study papillae were found on the abaxial epidermis of all species except M. elongata . Papillae have also been reported in M. allemi M. Silva (Silva et al ).…”

“…These cells can also be dispersed among the vascular bundles, as found in Ottonia martiana (Souza et al ), and in a few taxa (e.g. species of Citrus, Jatropha ) they completely surround the vascular bundles and form a sclerenchymatous sheath, as seen in Manihot species (Cunha Neto et al , Silva et al ).…”

“…The cylindrical type seems to be the most common in Manihot . Cunha Neto et al () studied six wild Manihot species from the Northeast Region of Brazil and found two species with flattened petioles, whereas Vannucci (), Allem (), Mendonça () and Silva et al () found only the cylindrical type.…”

“…(Euphorbiaceae) is a neotropical genus with 98 species distributed from Texas to Argentina according to Rogers and Appan (). However, several species have been described since the publication of the most recent taxonomic revision of the genus, which would increase this number to more than 120 species (Martins and Ledo , Cordeiro et al , Silva et al ). In addition, based on recent morphological studies (Duputié et al , Martins et al ), some names are now treated as synonyms, indicating the taxonomic complexity of the genus.…”

“…Despite this, leaf anatomy and micromorphology of only a few Manihot species have been studied. To the best of our knowledge, only the studies by Vannucci (), Allem (), Mendonça (), Cunha Neto et al () and Silva et al () provide some information on the anatomy or micromorphology of Manihot leaves. The majority of the studies about this group deal with cassava breeding or the evaluation of anatomical characteristics of stems and roots of hybrids, cultivars and wild species for economical purposes (Graciano‐Ribeiro et al , , Nassar et al , Bonfim et al ), and only two studies analyze the anatomy of reproductive organs (Toledo , Oliveira and Oliveira ).…”