CYCADALES 



133 



while still in the pollen tube, they measure about 200 microns in 

 diameter and 275 microns in length. After leaving the tube, they 



Fig. 142. — Stangeria paradoxa: nucellus with pollen tubes after the tubes have bro- 

 ken entirely through the nucellus. In one pollen tube, the body cell has divided to form 

 the two sperms (January 19, 1913); Xso. — From Ch.amberlaiNj The Living Cycads^'" 

 (University of Chicago Press). 



Fig. 143. — Stangeria paradoxa: two sperms have been formed from each body cell 

 (February 2, 1913); X50. — From Chamberlain, The Living Cycads^^° (University of 

 Chicago Press). 



increase in size, reaching a diameter of 230 microns and a length of 

 300 microns. Consequently, they are easily visible to the naked eye. 



