STRUCTURE OF MAIZE 



147 



foot or more in length. Near the base of the silk on the side 

 opposite the embryo there is an opening through the ^vall oi 

 the ovular}' to ^vhich has been given 

 the name st^'lar canal. It is not 

 known positively whether the pollen 

 tube passes down through the sub- 

 stance of the silk, entering the ovulary 

 by way of the base of the silk, or 

 whether the pollen tube enters the 

 ovulary through the stylar canal. 

 Guignard and others believe the 

 latter to be the case.^^ Whether the 

 pollen tube before entering the stylar 

 canal grows dow^n the outside of the 

 silk or whether the pollen grain by 

 some mechanical means reaches the 

 opening to the stylar canal is likewise 

 unknown. After pollination, the silk 

 dries up but persists. When, however, pollination is prevented, 

 the silk grows to unusual size and remains green two or three 

 times as long as normal. 



217. The Ear. — The ear may vary from one-half an inch to 

 sixteen inches long and may have from four to forty-eight rows 

 in individual ears. A variation o[ from four to twelve inches in 

 length and from eight to t^vent}^-four row^s is not uncommon and 

 may obtain as a variety characteristic. 



The ear may be looked upon as being formed by the growing 

 together of four or more spikes, each joint of the rachis bearing 

 two spikelets. Each spikelet is two-flowered, the lower one 

 being abortive (214); thus the distinctly paired rows often 

 observed represent a pair of spikelets. The growing together 



1 Guignard, L.: La double fecondation dans le mais. Jour. d. Bot 15 : 1-14. 

 No. 2, 1901. 



2 Poindexter, C. C: The Development of the SjMkelet and Grain of Com 



Ohio Naturalist, VoL IV, No. i, Nov. 1903. 



A spikelet of maize before fertiliza- 

 tion ; s, style or silk ; c, the stylar 

 canal through which, perhaps, the 

 pollen tube enters the ovulary ; 

 i, inner glume; c, outer glume. 

 Enlarged twelve times (after 

 Poindexter) . 



