Manihot Manihotoides (Euphorbiaceae) - CNCFlora

Systematic Position of the Genus 33
"bitter" (poisonous) or "sweet" (nonpoisonous) to the major name. In Brasil, aipim or
macachiera may be used rather than "sweet" to differentiate those cultivars used as a
fresh vegetable. All these names (or some equivalent sound) seem to have been in use by
natives in the Western Hemisphere tropics, and may apply either to the plant or to one of
its useful products. For example, cassava (or cassabe) generally describes a large, dried
cake made from the ground and dried root. Beju also refers to this product in Brasil.
The major useful part of the plant is the starch-filled tuberous root, most often
produced as an adventitious root from stem cuttings. However, in parts of Africa,
particularly in the former Republic of the Congo (now designated Zaire), the foliage is
eaten as a spinach with great regularity, and in considerable quantities. Use of the foliage
is infrequent in the tropics of the Western Hemisphere.
The roots may be used as a fresh vegetable, in a manner similar to use of the tubers
of Solanum tuberosum, if the cultivar is known to produce roots with low concentrations
of HCN. There are apparently no roots completely devoid of the poisonous substance,
but in the "sweet" variations, most of the HCN is confined to the outer layer, or
phelloderm. Those not entirely familiar with this cultigen would be well advised to treat
all cultivars as poisonous, and to process them sufficiently to reduce the concentrations
of HCN to tolerable levels.
By far the largest food use of the roots follows a series of processes intended to
remove the HCN (though recent evidence indicates that a trace of HCN remains after the
best processing techniques), and perhaps to impart some desirable flavor to the product.
In Brasil, the largest consumer of M. esculenta, much of the crop is produced as farinha, a
dry meal eaten alone or in combination with many other foods. Gari, a product found in
west Africa, is similar to Brasilian farinha. The number of variations on methods of
preparation of the roots is almost endless. Frequently, a fermentation, or microbial
conversion process, is employed in food production. Apparently, the flavors added by
fermentation make the processed food more palatable. Tapioca is one of the best known
of cassava products reaching the temperate zone markets.
The starch from M. esculenta roots may be used in various industrial processes, such
as paper sizing, in corrugated paper, or boxes, in many fillers where starches are
important. Dried chips from the roots are imported into western Euorpean nations as part
of cattle and hog rations.
NOMENCLATURE. The nomenclatorial history of this species reflects, to some
extent, the development of species concepts from their inception to the present. Linnaeus
(1753) named the cultigen Jatropha Manihot. He did not accept Manihot as a separate or
recognizable genus although European botanists used Manihot as a distinct taxon more or
less equivalent to a genus for nearly 100 years before 1753. Linnaeus' inclusion of the
cultivated species in Jatropha caused considerable confusion in the literature until the
monographic work of Pohl, who, in 1827, definitively described the genus and many
other species of the genus. Although Pohl's work was the definitive one, Miller, in 1754,
is credited with the first post-Linnean application of the generic term. Miller intended to
use an epithet first applied by Bauhin in 1651, M. theveti, but since he did not clearly
espouse a strict binomial system (frequent polynomials) his species epithet is not
permitted, and the name esculenta, first used by Crantz in 1766, becomes the first valid
name for the cultivated species. Crantz's name was not recognized, however, until Pax's
monograph in 1910, where the epithet was listed in synonymy underM. utilissima Pohl,
and was not generally accepted until 1938, when Ciferri applied the modern concept
wherein all the cultivars, with both high and low concentrations of the cyanogenic
glucoside, are members of the same highly variable species.
Many of the species epithets applied to M. esculenta are mere nomenclatorial
synonyms, but several are here placed in synonymy for the first time, because we employ
a broader concept of the species than any previous students. Thus, M. flabellifolia Pohl,
M. digitiformis Pohl, M. diffusa Pohl, M. loureirii Pohl, M. melanobasis Muell.-Arg., M.