THE SPERM A TOI'IIYTA 



353 



As its name implies, the reproductive structures in this order 

 are typically produced in cones. The microsporangial (staminate 

 or "male") cones (Fig. 223) are short-lived and somewhat 

 delicate structures, and each cone-scale (stamen or microsporo- 

 phyll) bears two (rarely more) microsporangia on its lower or 

 dorsal surface, in which the microspores or pollen grains are 



Fig. 224. — Ovulate or "female" cones of the pine. 



developed (Fig. 218). The pollen is in all cases transferred to the 

 ovules by wind. Except for the rather small group Taxaceae, 

 in which cone-scales or integuments become fleshy at maturity, 

 the megasporangial (ovulate or "female") cones (Figs. 224 and 

 225) usually become hard and woody. Each cone-scale bears one 

 or two ovules. In most cases the embryo-sac is distinctly smaller 

 than that of the cycads and contains fewer cells (Fig. 217). The 

 pollen alights on the nucellus and there germinates (Fig. 218). 

 The generative cell at this time divides into two, a stalk cell and 

 a body cell, which are believed to represent the remains of an 

 antheridium. The body-cell in time follows the tube-nucleus 

 down the pollen tube and divides into two male cells, one of which 

 effects fertilization (Fig. 226). No pollen-chamber is formed, but 

 the pollen-tube conveys the male cells, which are non-motile. 



