by L.H. Bailey, Cyclopedia of American Horticulture 1903
ZÈA (an old Greek name for some common cereal, probably spelt). Gramíneæ. As now limited the genus is founded upon the single polymorphous cultivated species Zea Mays, Maize or Indian Corn (Figs. 2772, 2773), whose origin is unknown but is suspected by some to be Teosinte (Euchlæna Mexicana). Most of the evidence points to Mexico as the region in which it originated and from which it spread. Under the head of Corn are given the botanical characters of the genus, a classification of subspecies of Zea Mays, and a discussion of Sweet Corn and Pop Corn. A picture of a staminate flower is given in connection with the article Grass. Hackel (“The True Grasses”) explains the fructification of Maize as follows: “The pistillate spikes (originally by monstrous or teratological development?) are grown together into a spongy, continuous, club-shaped body (the cob) upon which the 4-11 double rows (each sessile upon a low longitudinal elevation that is limited by a long, shallow furrow on each side) correspond to a single spike of Euchlæna. Grain developed at the expense of the other parts, projecting beyond the thin bracts, which rarely become coriaceous and inclose it.” Fig. 2773. The staminate flowers are in the “tassel.”
Dent or Field Corn (Z. indentata, of Sturtevant). The bulk of the Corn raised for home use and for export belongs to this subspecies. It is characterized by the presence of horny or corneous endosperm along the sides of the grain, while the starchy endosperm extends to the summit. In drying, the floury portion shrinks more than the horny, and this gives rise to the dent at the summit. Both the horny and the floury portion of the endosperm consist of starch, but the former is more compact. The varieties vary greatly in size of plants and appearance of the ear, but in general the plant and the ear are both larger than the Sweet or Flint Corns. The color of the kernels varies, the chief color varieties being white, yellow, and calico, the latter mottled with red; red varieties are less common, but red ears occasionally occur in all varieties.
Flint Corn (Z. indurata, Sturt.). Kernel with horny endosperm enveloping a starchy or floury portion, this being hard and flinty and with no dent at apex. Ears in most varieties smaller and rows fewer (often 8) than in the Dent Corn. Color of kernel white, yellow, red, blue, and variegated. Commonly cultivated through the northern portions of our country and in Canada, where the seasons are too short for Dent Corn. Has been grown as far north as 50°.
Soft Corn (Z. amylacea, Sturt.). Kernels without horny or corneous endosperm, hence shrinking uniformly. Seems to have been commonly grown by the Indians in many localities of both North and South America. At present it is cultivated to only a limited extent in the United States. Brazilian Flour Corn sold by seedsmen is a type of the Soft Corn.
Pod Corn (Z. tunicata, Sturt.) is sometimes grown as a curiosity. Each kernel is inclosed in a small husk and the whole ear again inclosed in the usual husk.
A form of Flint Corn with variegated leaves goes under the name of Zea Japonica, or Japanese striped Corn. Z. quadricola and Z. gracillima are seedsmen’s names for other similar forms, the former being variegated and the latter dwarf.
The origin of Maize is still a mystery. All evidence points to an American nativity, but the original form of the species is not identified. Many persons believe that the wild original will yet be found somewhere from Mexico south. Others suppose that Maize originated from the Teosinte (Euchlæna Mexicana), a fodder grass that is much grown in Mexico. This latter view has arisen from experiments in crossing Teosinte and Maize, whereby a maize-like plant has been produced, thus showing the very close affinity of the two species. Plants of this hybrid were thought by the late Sereno Watson and others to constitute a new species of Zea, and Watson named it Z. canina. This plant quickly reverts to ordinary Corn when grown in the North (see Harshberger, G. F. 9:522; Contr. Bot. Lab. Univ. Penn. 2:231. Also Bailey, Bull. 49, Cornell Exp. Sta.). Figs. 2774, 2775. Zea Mays, therefore, may be (1) a true species, of which the wild prototype is unknown; (2) a direct offshoot by domestication of Euchlæna Mexicana; (3) a direct offshoot by domestication of Euchlæna Mexicana; (4) a product of crossing between Euchlæna Mexicana and a domesticated race of the same species. Our knowledge is yet insufficient to enable us to offer much more than conjecture on these categories.
Maize is remarkably variable, although most of the variations intergrade in different regions and under different conditions. The most extended American study of variation and varieties in Maize has been made by the late Dr. E. Lewis Sturtevant. The summary of his study of varieties is published as Bull. 57, Office of Experiment Stations, U.S. Dept. of Agric. (“Varieties of Corn,” 1899). Sturtevant throws the varieties of Maize into seven “species groups” or “agricultural species.” The distinguishing characters of these groups are founded on the kernels. Aside from these there is at least one well-marked race of ornamental maize, Zea Japonica, which for horticultural purposes may well be separated from the others. In the following classification, the characters of the races, except of the ornamental sorts, are copied from Sturtevant. It is probable that a strict inquiry into the nomenclature of Zea Mays would find other names to replace some of those given by Sturtevant; but his names have the great merits of definiteness and of applicability to American forms of Maize.
Zèa Màys, Linn. Maize. Indian Corn. A composite species, of which no single form can be taken as the type. Linnæus meant the name to cover the whole range of forms then grown in European gardens. Tender annual. If an original specific form of Maize were to be discovered, this form would no doubt be taken as the type, and all other forms ranged as varieties of it.
A. Maize grown for ornament.
Var. Japónica, Koern. (Z. Japónica, Van Houtte. Z. vittàta, Hort.). Foliage variously striped with white: plant small. Said to have come from Japan. F.S. 16:1673-4. Ears small; kernels yellowish, flint.
Var. gracíllima, Koern. (Z. gracillíma and Z. mínima, Hort.). Very dwarf, slender form with green lvs., sometimes cult. in Eu. A variety variegata is also mentioned.
Var. Curágua, Alef. (Z. Curágua, Molina), is described as a very robust green-leaved form. Sturtevant places it in the Pop Corn tribe.
AA. Maize grown primarily for the grain or fruit.
Var. tunicàta (Z. tunicàta, Sturt.). Pod Corn. Figs. 2777, 2778. In this group each kernel is inclosed in a pod or husk, and the ear thus formed is inclosed in husks.
Var. evérta (Z. evérta, Sturt.). Pop Corn. This group is characterized by the excessive proportion of the corneous endosperm and the small size of the kernels and ear. The best varieties have a corneous endosperm throughout. This gives the property of popping, which is the complete eversion or turning inside out of the kernel through explosion of the contained moisture on application of heat. A small deposit of starchy endosperm does not greatly interfere with this property of popping, but when the starchy endosperm is in excess, as in a flint Corn, the kernel does not evert, but the corneous portion only explodes or splits, leaving the starchy portion unchanged. The true Pop Corn is hence tender in its heating; the false Pop Corn has a tender portion of limited extent only This class of Corns is even more readily recognized by inspection than by description.
Var. induràta (Z. induràta, Sturt.). Flint Corn. Fig 2779. A group readily recognized by the occurrence of a starchy endosperm, inclosed in a corneous endosperm, as shown in a split seed. This corneous endosperm varies in thickness with varieties. When very thin at the summit of the kernel the shrinkage of the starchy endosperm may cause a depression, thus simulating externally a dent from which its structure at once differentiates it.
Var. indentàta (Z. indentàta, Sturt.). Dent Corn. Fig. 2780. A group recognized by the presence of corneous endosperm at the sides of the kernel, the starchy endosperm extending to the summit. By the drying and shrinkage of the starchy matter the summit of the kernel is drawn in or together, and indented in various forms. In different varieties the corneous endosperm varies in height and thickness, thus determining the character of the indented surface.
Var. amylàcea (Z. amylàcea, Sturt.). Soft Corns. This group is at once recognized by the absense of corneous endosperm. Through the uniformity of the shrinkage in ripening there is usually no indentation, yet in some varieties an indentation may more or less frequently appear, but splitting the kernel infallibly determines the class.
Var. saccharàta (Z. saccharàta, Sturt.). Sweet Corn. Figs. 2781, 2782, A well-defined group characterized by the translucent, horny appearance of the kernels and their more or less crinkled, wrinkled, or shriveled condition.
Var. amylea-saccharàta (Z. amylea-saccharàta, Sturt.). Starchy-sweet Corn. This group is founded upon three varieties found in the San Pedro Indian collection of Dr. Palmer and sent in 1886. The external appearance of the kernel is that of a sweet, but examination shows that the lower half of the kernel is starchy, the upper half horny and translucent. These varieties all had a white cob, the kernels deeper than broad.