534 



BOTANY OF THE LIVING PLANT 



attached laterally (the generative cell), and a free nucleus (the tube 

 nucleus) enclosed in cytoplasm which fills the rest of the grain. 



Fig. 421. 

 Pinus montana. A longitudinal section of a ripe male flower (xio). B, longitu- 

 dinal section of a single stamen ( x 20). C, Transverse section of a stamen ( x 27). 

 D, a ripe pollen grain of Pinus sylvestris. The obliterated prothallial cells are not 

 shown. ( x 400.) (After Strasburger.) 



The male flower is thus a simple shoot bearing sporangia. The 

 female flower may also be regarded as a simple shoot. It consists of 

 an axis bearing numerous scales that are at first succulent, but finally 



Fig. 422. 

 Median section of ovule and scales in Pine at time of pollination (after Coulter). 

 b. sc= bract scale, ov. sc = ovulif erous scale. « = nucellus. t' = integument. tn = 

 micropyle. e.s. = embryo-sac. As the two ovules lie side by side, only one of them 

 is seen in the radial section. p = pollen-grain on nucellus. 



woody. They are arranged on a complex spiral plan. One of these 

 scales removed from the young pink cone at the stage of pollination 

 shows a double structure. A smaller lobe, sometimes called the 



