EXPLANATION OF THE ILLUSTRATION 
Prare IV 
A. Maize (Chapalote, Sinaloa) 
B. Maize (Confite Morocho) 
C. Teosinte (Chalco) 
D. Teosinte (El Valle) 
Explanation 
Both A and B show relatively pure maize patterns. In comparing 
these photographs with those of two teosinte races on the right, a 
second feature of maize-teosinte exine difference can be seen. The 
spinules of the maize grains are darker and thus more distinct. This 
suggests the spinules (and supporting columellae) of the maize-type 
exine are longer, causing more phase retardation than those of teo- 
sinte. One practical result is that larger areas of the exine of maize 
‘an be brought into sharp focus (with grains of the same size). Cor- 
responding photographs were taken and printed under virtually iden- 
tical conditions. 
C and D differ in significant ways. D is a primitive teosinte (that 
is, with little maize contamination). C isa teosinte with a high amount 
of maize germ plasm. The only observable difference between the 
latter and typical maize is the amount of phase retardation of the 
spinules, discussed above. ‘Teosinte Chalco is also one of the most 
maize-like of modern teosintes in other aspects of plant morphology. 
