212 



MORPHOLOG V. 



tire scale according to this view is a carpel, or sporophyll, which is divided 

 into the cover scale and the ovuliferous scale. This division of the sporophyll 

 is considered similar to that which we have in isoetes, where the sporophyll 



Fig. 273. Fig. 274. Fig. 275. Fig. 276. 



Archegonium of Picea Archegonium of Picea Embryo of Pine seedling just 

 vuigaris, sperm cell ap- vulgaris showing fusion white pine re- emerging from the 

 preaching the nucleus of of sperm nucleus with moved from ground, 

 egg cell. egg nucleus. seed, showing 



several coty- 

 ledons. 



Figs. 273, 274. Fertilization in picea. (After Strasburger.) 



has a ligule above the sporangium, or as in ophioglossum, where the leaf is 

 divided into a fertile and a sterile portion. 



A more' recent view regards each cone scale as a flower, the ovuliferous 

 scale composed of three united carpels arising in the axil of a leaf, the cover 

 scale. Two of the carpels are reduced to ovules, and the outer integument 

 is expanded into the lateral portion of the scale, while the central carpel is 

 sterile and ends in the point or mucro of the scale. 



