PAST HISTORIES OF PLANT FAMILIES 



i ii 



bearing sacs (which bear no inconsiderable likeness to 

 fern sporangia), the whole cone reaching i|- ft. in length 

 in some genera, and weighing several pounds. All the 

 other Gymnosperms, except the Araucarese, where they 

 are an inch or two long, have male cones but a fraction 

 of an inch in length. 



In all the members of the family, 

 excepting Cycas itself, the female 

 fructifications also consist of similarly 

 organized cones bearing a couple of 

 seeds on each scale instead of the 

 numerous pollen sacs. In Cycas the 

 male cones are like those of the other 

 genera, and reach an enormous size; 

 but there are no female cones, for the 

 seeds are borne on special leaflike 

 scales. These are illustrated in fig. 

 75, which shows also that there are 

 not two seeds (as in the other genera 

 with 'cones) to each scale, but an 

 indefinite number. 



The leafy nature of the seed- 

 bearing scale is an important and in- 

 teresting feature. Although theoreti- 

 cally botanists are accustomed to 

 accept the view that seeds are always 

 borne on specially modified leaves (so 

 that to a botanist even the " shell" 

 of a pea-pod and the box of a poppy 

 capsule are leaves), yet in Cycas alone among living 

 plants are seeds really found growing on a large struc- 

 ture which has the appearance of a leaf. Hence, from 

 this point of view (see p. 45, however, for a caution 

 against concluding that the whole plant is similarly lowly 

 organized), Cycas is the most primitive of all the living 

 plants that bear seeds, and hence presumably the likest 

 to the fossil ancestors of the seed-bearing types. In this 

 ^character it is more primitive than the fossil group of 



Fig. 75. Seed-bearing 

 Scale of Cycas, showing its 

 lobed and leaflike character 



s, Seeds attached on 

 either side below the divi- 

 sions of the sporophyll. 



