EVOLUTION, HOMOPLASY, ANALOGY, HOMOLOGY 353B 



in certain ancient fossils of relatively simple form, such as the Psilophytales 

 (Fig. 3 72 a) : while each sporogonium of a Bryophyte might also be held as an 

 isolated telome (Fig. 352). 



The fertile telome consists of a distal tract containing spores, seated on a 

 stalk usually traversed by a vascular strand that conveys nutrition from below. 

 Here as elsewhere the function of nutrition precedes spore-formation, hence the 

 distal position of the fertile cyst, or sporangium. This biological succession of 

 events underlies the scheme of development of all self-nourishing vegetation. 

 It has been further suggested that the whole wealth of form that characterises 

 living cormophytes may have been built up from such telome-units, by branch- 

 ing and general elaboration that has resulted in the vegetative system that bears 

 the fertile region distally. 



The detailed realisation of cumulative growth in producing from individual 

 telomes complex bodies, such as are seen in the Higher Plants, has been imagined 

 as yet, rather than demonstrated by actual developmental observation, or by 

 comparison of successive stages of branching. And a vast amount of compara- 

 tive study, of early fossils as well as of living plants, will be required before 

 such an origin could be accepted as other than frankly speculative, rather than 

 demonstrational. 



