e
continent from New England to Chili. Its cultivation must have been
extremely ancient, for Tschudi[566] describes two kinds, now extinct or
not known in Peru, which were taken from tombs apparently prior to the
dynasty of the Incas. But there is even stronger evidence of antiquity,
for I found on the coast of Peru[567] heads of maize, together with
eighteen species of recent sea-shell, embedded in a beach which had
been upraised at least 85 feet above the level of the sea. In
accordance with this ancient cultivation, numerous American varieties
have arisen. The aboriginal form has not as yet been discovered in the
wild state. A peculiar kind,[568] in which the grains, instead of being
naked, are concealed by husks as much as eleven lines in length, has
been stated on insufficient evidence to grow wild in Brazil. It is
almost certain that the aboriginal form would have had its grains thus
protected;[569] but the seeds of the Brazilian variety produce, as I
hear from Professor Asa Gray, and as is stated in two published
accounts, either common or husked maize; and it is not {321} credible
that a wild species, when first cultivated, should vary so quickly and
in so great a degree.

Maize has varied in an extraordinary and conspicuous manner.
Metzger,[570] who paid particular attention to the cultivation of this
plant, makes twelve races (unter-art) with numerous sub-varieties; of
the latter some are tolerably constant, others quite inconstant. The
different races vary in height from 15-18 feet to only 16-18 inches, as
in a dwarf variety described by Bonafous. The whole ear is variable in
shape, being long and narrow, or short and thick, or branched. The ear
in one variety is more than four times as long as in a dwarf kind. The
seeds are arranged in the ear in from six to even twenty rows, or are
placed irregularly. The seeds are coloured--white, pale-yellow, orange,
red, violet, or elegantly streaked with black;[571] and in the same ear
there are sometimes seeds of two colours. In a small collection I found
that a single grain of one variety nearly equalled in weight seven
grains of another variety. The shape of the seed varies greatly, being
very flat, or nearly globular, or oval; broader than long, or longer
than broad; without any point, or produced into a sharp tooth, and this
too