84 lPostelsia 



6. The so-called cotyledons of the 

 Pteridophytes and Gymnosperms, with 

 the probable exception of Ginkgo and 

 the Cycads, are true foliage-leaves. 



Notes. 



i. The exact method of origin of 

 the so-called cotyledons of Ginkgo and 

 the Cycads is unknown, but their posi- 

 tion at the base of the stem and 

 their conduct during germination are 

 strong evidence in favor of the view 

 that they are homologues of the 

 feeders of Gnetum and Welwitschia, 

 and hence true cotyledons. 



2. In Gnetum the suspensor some- 

 times branches, when an embryo is 

 produced on the end of each branch. 



3. The repeated displacement of 

 the cotyledon to different points on 

 the circumference of the embryo would 

 seem to indicate that an area entirely 



