496 WEATHERWAX: SPIKELETS OF ZEA MAys 
Explanation of plate 23 
Fic. 1. Embryo sac, E, egg; SS, min F, polar suclel; A, antipodal tissue. 
Fic. 2. Another section of the embryo sa 
Fic. 3. Very young pistil, X 60. S, one coe of silk; W, enciis of ovary 
wall. ' 
Fic. 4. Section through the middle of an anther just before the reduction di- 
vision, X 50. 
Fic. 5. Section through the middle of a mature anther, X 50. 
Fic. 6. Section from near the distal end of the anther tans in FIG. 5. 
Fic. 7. A mature anther, X ro. 
Fic. 8. Section of pollen grain, howink-s germ pore, vegetative ete and the 
two sperms, X 550. 
Fic. 9. Portion of a longitudinal section of a stamen of the female flower, just 
before disorganization begins, X 200. E, epidermis; 7, tapetal region; P, pollen 
mother cells. 
