353A 



BOTANY OF THE LIVING PLANT 



whole evolutionary sequence, there can be little doubt of the Homology 

 of the sexual process in them all, and in the gametangia which produce the 

 gametes themselves. 



The determination of all questions of homogeny, homology, and 

 analogy must ultimately be based upon a knowledge of Descent. 

 Until the phyletic lines for any series of plants are demonstrated the 

 recognition of such relations of their parts cannot rest on more than 

 carefully balanced opinion. A comparative examination of organisms 

 lower in the scale, and ultimately a grouping of them into phyletic 

 sequences, will therefore be necessary before a final basis can be found 

 for the classification of their parts. The point of view from which 

 their study is at present to be approached is that they will supply a 

 basis, however imperfect, for such a classification. This will not only 

 help to explain their own mutual relations, but also to illuminate the 

 morphology and classification of plants higher in the scale of Vegeta- 

 tion. It is only by such comparative study that the details of the 



structure and propagation seen in 

 the Higher Flowering Plants can be 

 reasonably interpreted. In par- 

 ticular, the Seed, which is the most 

 distinctive feature of the Higher 

 Plants, cannot be properly under- 

 stood unless it be shown by com- 

 parison with more primitive plants 

 how that very complex body came 

 into existence. 



Sporangium 



Phylloid 



~ Telome 



Sporang ienstan d PhylLoi dstand 



Telomstdnde 

 Fig. 264A. 



Diagrams of "Telome und Telomstande," 

 after Zimmermann ; fertile to the left, sterile 

 to the right. 



Telome. 



The term " Telome " has been re- 

 cently introduced by Zimmermann to 

 connote a category additional to the 

 parts of the sporophyte already recog- 

 nised in this chapter as taking part in 

 the organisation of cormophytic plants 

 (see Zimmermann " Phylogenie der 

 Pflanzen." Jena, 1930, pp. 58-70). The 

 telome is associated specially with spore- 

 production, and is in fact a primitive 

 spore-producing organ, whether the in- 

 dividual be sterile or fertile. Its recog- 

 nition tends to clarify the morphological 

 analysis of plants of complex construc- 

 tion. But it is most readily recognised 



