ZEA MAYS 113 



for some distance above the node from which it arises and its edges 

 overlap on the side of the axis distal to the blade. According to 

 Weatherwax (xi), the collar-like ligule develops from the adaxial 

 epidermis at the top of the sheath, fitting tightly around the stem 

 and the blades or sheaths of the included leaves. The long, flat 

 blade is auricled at the base and is somewhat fluted or wavy along 

 its edges at maturity. This results from inequalities in the growth 

 rate of the marginal and central cells of the leaf. There is a promi- 

 nent midrib with many smaller, parallel veins which do not anas- 

 tomose with one another directly, but may be cross-connected 

 at frequent intervals by transverse veinlets. The number of leaves 

 on a given axis is variable, ranging from 10 to 18 or more. 



The Inflorescences. — Corn is monoecious, normally producing 

 staminate and carpellate flowers on separate inflorescences on the 

 same plant. The staminate flowers are borne on a terminal panicle 

 (tassel) consisting of a central spike and several lateral branches 

 or rachises arising from the central spike in a spiral arrangement. 

 The carpellate inflorescence (ear) originates in the axil of one of 

 the lower leaves and is borne on a short branch or shank. Leaves 

 arise from each node of the shank and form the husks of the ear. 

 The internodes of the shank are but slightly elongated, the upper 

 ones being progressively shorter than the lower so that the husks 

 overlap one another closely. In most cases, the leaves which form 

 the husks are only partially developed; but occasionally they may 

 have normal blades and ligules. 



Variations in the monoecious condition are not uncommon. 

 Plants may develop which have staminate inflorescences only. In 

 other cases portions of the tassel, usually the central spike, pro- 

 duce carpellate spikelets bearing fruits. Another variation con- 

 sists in the development of staminate flowers on the ear, usually 

 near its apex; and functionally perfect flowers have been known to 

 occur. In suckers, the inflorescences formed may be normal ears 

 or normal tassels or there may be any of the variations noted above. 



ANATOMY 



The Mature Grain. — The fruit of maize is a caryopsis in which 

 the pericarp, remains of the integumentary tissue, and nucellar 

 membrane are so intimately connected at maturity as to appear 

 fused. The mature grain. consists of the hull which is made up of 

 the pericarp and remains of the integuments, which may or may not 



