RffE CONES 353 



Ovuliferous scale and adheres to the ripe seed, forming a wing 

 which aids in dispersal by the wind (Fig. 205, E, w). In 

 Cephalotaxus and a few other genera the ripe seeds are plum-like, 

 resembling those of Cycads. 



The cones also undergo considerable enlargement in ripening, 

 often becoming many times larger than they were prior to 

 fertilisation (Fig. 200). The ripe cone-scales are usually woody, 

 and gape apart to set free the seeds, although in the Cedar, for 

 instance, they are shed with the latter. At this stage the bract- 

 scales in Pinus are no longer recognisable, though in some of the 

 related forms (e.g. the Douglas Fir, Pseudotsuga douglasii, Fig. 

 205, F), they are conspicuous even in the mature cone. The 

 Juniper is peculiar in that the cone-scales become fleshy, forming 

 a berry-like structure (Fig. 205, C) in which the ripe seeds are 

 embedded ; the seeds are in this case distributed by birds. 



In the life-history of the Conifers the method of fertilisation 

 shows a considerable advance on that of Cycads, since the pollen 

 tube, which is there but an organ for the absorption of nourish- 

 ment from the nucellus (a function which it may also fulfil to 

 a slight extent in the Conifers), is here utilised to convey the 

 motionless male cells to the egg. Thereby the necessity for 

 the presence of liquid water at the time of fertilisation is dis- 

 pensed with, and we may see herein the loss of the last traces 

 of the probable aquatic ancestry of the Vegetable Kingdom. 



