60 SURVEY OF THE REPRODUCTIVE PROCESS 



development, but it is renewed in germination by the up- 

 ward gro\\i;h of one of tbe embryos, and tlie consequent 

 emergence of the plumule and radicle of the young plant, as 

 in the case of other seeds. 



This sketch of the reproductive process in the Coniferae 

 will suffice to show its leading relations, both to the other 

 Phanerogamic orders and to the Cr^^togamia. 



The main points of agreement mth the latter are : — 



1. The nakedness of the ovule at the time of im- 



pregnation. 



2. The develoj)ment in its interior of the albumi- 



nous body and corpuscula, representing the 

 prothallium and archegonia. 



3. A certain amount of cellular development inside 



the pollen grain. 



4. The arrest in the development of the pollen 



tube, which divides it into two stages, admit- 

 ting of comparison with the maturation and 

 emission of the microspore, and the subsequent 

 evolution and discharge of antherozoids from it. 



The points again in which the Coniferse depai't from all 

 Cryptogamic, and agree ^ith other Phanerogamic plants, are 

 principally the following : — 



1. The adhesion of the ovule to the parent plant 



till after impregnation and the formation of 

 the embryo. 



2. The lapse of time between the formation of the 



embryo and its evolution in germination ; this 

 is the period of the latent life of the seeds, 

 during which their fall and dispersion take 

 place. 

 8. The substitution of fo villa in a pollen tube, in 



