ORIGIN, CLASSIFICATION, VARIETIES OF CORN 177 



late spikes produced in the tassel of the lower branches. 

 As each spike is made up of a double row of spikelets, 

 each spikelet being two-flowered with the lower flower 

 abortive, the result of such a fusion would be an ear having 

 distinctly paired rows of grains. This we find to be a 

 characteristic of an ear of maize. The cob is supposed to 

 have been formed from the growing together of the rachi 

 of the spikes. 



Observations made by Montgomery have led him to 

 think that "instead of the ear originating from the fusion 

 of a number of two-rowed spikes, it developed directly 

 from the central spike of some tassel-like structure similar 

 to the well known corn tassel." Montgomery states 

 further "that corn and teosinte may have had a common 

 origin, and that in the process of evolution the cluster of 

 pistillate spikes in teosinte were developed from the lateral 

 branches of a tassel-like structure, while the corn ear 

 developed from the central spike. It is probable that the 

 progenitor of these plants was a large, much-branched 

 grass, each branch being terminated by a tassel-like 

 structure bearing hermaphrodite flowers." 



It has been suggested by Harshberger that our culti- 

 vated maize is of hybrid origin because of the fact that 

 fertile hybrids of teosinte and maize are known and de- 

 scribed by Watson as Zea canina. As a speculative ex- 

 planation of such an origin it is suggested that the starting 

 point was a "sport of teosinte which then crossed itself 

 with the normal ancestor, producing our cultivated corn." 

 Zea canina is found growing wild in Mexico. 



CLASSIFICATION OF MAIZE 



According to Sturtevant, maize may be classed into the 

 following "agricultural species": 



