78 CHAPTER VI 



distance a patch of this grass looks very much like maize ; while 

 it grows to a height of five to ten feet, the stem is slender and 

 the leaf about half the width of the maize leaf. The plant 

 bears a tassel-like structure at the top and on the lateral 

 branches, closely resembling the maize tassel, except that the 

 seeds are borne on the lower part of each tassel and the pollen 

 on the upper part. 



Tcosinte, which is sometimes cultivated but does not 

 mature north of Mexico, is more like maize than is gama grass, 

 the plant being larger and the terminal tassel bearing pollen 

 only. The lateral branches of the plant are so shortened that 

 the terminal tassel-like structure is borne in a leaf axil sur- 

 rounded by a kind of husk as is an ear of maize, and bears only 

 pistillate flowers or seed. It is only a step in the production of 

 an ear of maize , from teosinte , by a development of the central 

 spike of the lateral tassel into an ear. 



It is probable that the early progenitor of maize was a 

 grass-like plant having a tassel at the top and a tassel-like struc- 

 ture on long, lateral branches, all tassels bearing perfect 

 flowers. As evolution progressed, the terminal tassel came to 

 produce only pollen, and the side branches only ovules, or seeds. 

 Evolution often results in a greater " division of labour," as 

 in this case. At the same time the lateral branches were shor- 

 tened or telescoped into the leaf sheaths, these sheaths forming 

 a covering or husk for the ear. Also it is probable that in this 

 evolution the central spike of the tassel developed into an ear. 

 The close relationship of maize and teosinte is proved by the 

 crosses that have been made between the two. In the third 

 or fourth generation after crossing, a peculiar type of corn is 

 secured, identical with a type of maize that has been found 

 growing wild in Mexico (Zea canina), and is supposed by some 

 persons to be the true wild maize and the progenitor of our 

 cultivated maize." O 



The maize plant is in many respects typical of the grasses. 

 It belongs to the Gramineag, and is a member of the Maydeae, 

 a tribe which is characterised by the separation of the pistillate 

 and staminate flowers. It is monoecious, and is both protan- 

 drous and protogynous, protandry being the rule in the chief 

 varieties in South Africa. While self-pollination is common, 

 cross-pollination is usually a factor which later will be shown 

 to have a very marked effect on productivity. 



Roots. — The root system is developed as follows : — First 

 the primary root appears, after this the temporary roots de- 



