SECTION II 



PHANEROGAMIA 



General Character. — The Phanerogams follow the Pteridophytes 

 without any sharply -defined barrier, representing phylogenetically 

 more highly-developed plant forms. Their more advanced develop- 

 ment is limited to the sporophyte, or asexual generation, which, while 

 still retaining a distinct segmentation into root and shoot, exhibits 

 more extensive differentiation and a greater variety of form, especially 

 in the formation and disposition of the sporophylls, than in the 

 Pteridophytes. On the other hand, this has been accompanied by a 

 reduction of the sexual generation, resulting in the complete loss of its 

 separate individuality. The sexual plant has been reduced to a few 

 cells, which are dependent upon the sporophyte for their existence. 

 Their recognition as the degenerate remnant of a once independent 

 generation was the result of a comparative investigation of their mode 

 of development. 



The Spore-forming' Generation. — The vegetative segmentation of 

 the Phanerogams has been already sufficiently described in the section 

 on General Morphology. Attention will only be given here to the 

 organs functioning in the service of reproduction and dissemination of 

 the spores, as they alone are specially characteristic of the Phanerogams 

 as a distinct class. 



The Phanerogams are all, without exception, HETEROSPOROUS. As 

 in the Selaginellaceae, macrospores and microspores are always pro- 

 duced by different sporophylls, which, for the most part, are borne 

 on the same shoot, although sometimes they arise on separate axes or 

 even on distinct male or female plants. The spores are also formed in 

 sporangia, which, just as in the Pteridophytes, represent organs sui 

 generis. 



The male sporophylls of the Phanerogams are known as STAMENS ; 

 the female sporophylls as CARPELS. Notwithstanding their different 

 designation, the staminal and carpellary leaves are in every respect 

 homologous with the sporophylls of the Pteridophytes, and are to be 



