while just above the permanent roots it was three-eighths by fiveeighths inch. The majority of the permanent roots begin at about one inch below the surface of the soil, regardless of the depth of planting. Brace roots, however, usually start from the node, one or two inches above ground. The aerial portion is much enlarged, but soon after entering the ground becomes reduced to the size of the other roots. A maize plant forty-three days old and five feet high was found to possess thirty-five roots, eleven of which were brace roots. None of the brace roots had entered the ground more than one and one-half inches. Their total length varied from one and one-half to five inches. An examination of the mature plants shows the brace roots to have grown to considerable depths, thus performing the function of true roots. Variety differences in ability to support the culm and prevent its being blown down have been observed, but this character has not as yet been made of practical value.1 210. Culms. The maize plant is the most variable in size of the cereals. The height is reported to vary from eighteen inches in the Tom Thumb pop to thirty feet or more in the West Indies. Individual stalks twenty-two and one-fourth feet high have been reported from Tennessee. From four to twelve feet is a common variation. The height varies not only with the variety but the same variety varies largely with soil and climatic conditions. Along the Mississippi River, south of the fortieth parallel, it is not unusual to see maize growing on which the ears are so high that a man of ordinary height can barely reach them. In the northern latitudes of the United States, as in New England, much maize is so short as to make it necessary to stoop to reach the ears. The circumference of an average maize culm, between the first and second nodes, in a dent or flint variety, will be from three to four and one-half inches. Unlike most of the plants of the grass family, the culm of maize is not hollow, the interior being filled with a soft pith, which does not add mate 1 Miss. Bul. 33, P. 75 rially to its strength. The internodes are alternately furrowed on the side next the leaf blade and on the side where the branch or ear may occur. In fact, furrows appear to occur for the accommodation of the branch or ear buds. The maize plant does not depend alone upon the node for erecting bent culms as in the other cereals and grasses generally, but the walls of the lower internode have a similar power. (378) The per cent of crude fiber is considerably higher in the outside of the culm than in the pith, thus increasing the per cent of other constituents in the latter. Aside from this, the per cent of ash is higher in the pith, being especially high in potassium and calcium, while the culm wall is notably high in silica. At the New York Station the rate of growth ranged from three to eighteen and one-half inches per week. Under specially favorable conditions a growth of five inches was recorded in one day.1 At the Illinois Station an increase in one week equal to 1,300 pounds of dry matter per acre was observed. 211. Suckers. Under conditions of ordinary culture, one seed produces but one culm. When, however, the planting is not sufficiently thick for the existing conditions, the plant may produce one or more branches from its lower nodes, which branches will throw out separate roots. The branches or culms are known as suckers, and usually do not produce ears. They are not desirable because they take plant food and water from the soil without giving any return in grain. Some varieties of maize produce a number of branches from nodes higher up the culm. Ordinarily, however, the maize plant is unbranched except where its one or more ears are produced, the ear being produced at the end of a much modified branch. (214) 212. Leaves. With dent maize grown in Iowa, the number of leaves on a culm varied from twelve to eighteen. Since the 1 C. S. Plumb: Indian Corn Culture, p. 14. 2 Iowa Bul. 2 (1888). lower leaves die off before maturity, activity at any one time is confined to about twelve. The width of the blade varied from three and three-quarters to five and one-eighth inches. At the Missouri Station the total external leaf surface on twelve living leaves of a single maize plant was found to be twenty-four square feet.1 As 12,000 plants per acre are not an unusual stand, the leaf surface may be more than a quarter of a million square feet on an acre, or about six times the area on which the plant stands. At the Michigan Station the leaves constituted somewhat more than a third of the dry matter when the grains were in milk, and a little more than a fifth when the plant was ripe. During this period the percentage of dry matter of culm remained about the same, the decrease in percentage of dry matter in leaves having been offset by a corresponding increase in the ears.2 The outer edges of the leaf blade grow faster than the portion next the midrib, giving a wavy effect to the blade and giving it an elasticity which aids it to withstand wind. In the upper portion of the blade, on either side of the midrib, are to be found large wedge-shaped (bulbiform) cells which on filling with water cause the young leaf to unfold and which during drouth cause the leaf to roll, thus reducing the evaporation from the plant. The under surface of the leaf is further protected, also, against transpiration by a strong cuticle. The ligule tightly clasps the stalk, preventing the entrance of water and accompanying dirt between sheath and culm: it also prevents the sheath from rotating upon the culm as in most of the grasses. 213. Relationship of Grain to Stover. Of two stalks bearing the same quantity of grain, the smaller is to be preferred, where grain is the principal object sought. The larger the stalks the more food material necessary to produce them, the more ground 1 Mo. Bul. 5 (1889). Mich. Bul 154 (1898), p. 272. is shaded, and, consequently, a less number of stalks can be raised per acre. In some localities the ear may be too high on the stalk to be husked easily. While there are wide variations due to variety', soil, climate and thickness of planting, the weight of field-cured stover has been esti mated at about one and one-third pounds for each pound of grain produced. In actual dry matter the yield per acre may be estimated as about equal under ordinary field culture. It has been estimated that for every pound of dry matter produced in the roots and stuk ble when cut close t the ground, six pound are produced in the plant above ground.1 214. The Inflores. The cultivated cence. maize plant bears its carpels and stamens in separate flowers. The staminate flowers borne in a panicle of Spikelets at the top of the culm are called collectively the tassel. The carpellate flowers are borne in the I Wis. Rpt. 1892, p. 119. In this connection, see also Mo. Bul 9. axils of the leaves, forming upon maturity what is known as the ear. The fruit of the maize plant being borne in the axils of the leaves rather than being terminal is a feature which distinguishes maize from all the other cereals. The difference is more apparent than real. Certain varieties of maize, especially pod maize, sometimes bear carpels upon the tassel of the main culm, and where branches oc cur bear both stamens and carpels at their end. It is assumed that wild naize was a branched plant containing perfect flowers (both carpels and tamens) on the terminal rassel and, also, at the nd of the branches. Since the plant is wind fertilized and the pollen ends to fall, the carpellate flowers in the terninal tassel would be less perfectly pollenized than those on the branches below. The pollen on the branches would tend to fall to the ground, thus being of little value. The plants which had the greatest development of carpels on the branches and of stamens in the terminal tassel would tend to survive. laden with a collection of grains (ear) the short branch would Compare with dent Note two good ears Flint maize, variety Smut Nose. As the end of a branch became |