SPERMATOPHYTES 



22T 



all traces of the mesarch structure have 

 disappeared, even from the cotyledons. 

 The leaves vary from narrow needles 

 (fig. 486) to broad blades and con- 

 crescent disks. When the blades are 

 broad, transversely elongated mesophyll 

 cells appear. 



Staminate StrobiluS. The StaminatC 



strobilus (fig. 487) is made up of spo- an earl y stage of the male e amet - 



phyte. After COULTER and CHAM- 

 rophylls (stamens) which are exceed- BERLAIN . 



ingly variable in form. In general, 



the stamen is bractlike, with sterile tip and abaxial sporangia (as in 

 cycads and podocarps), the sporangia most frequently two in number 

 (fig. 488), though sometimes more numerous ; but in the araucarians 



FlG 48(? _ The winged and shed _ 



ding pollen grain of pine, containing 



FIG. 490. Various views of the ovuliferous scales and ovules of pine: on upper sur- 

 face are borne two ovules (megasporangia) with micropyles directed towards the base of 

 the scale; the seeds become winged by tissue developed from the scale. 



