441 



gamete without any antithetic alternation whatever. Take as examples 

 Fucus or Vaucheria or Spirogyra. Perhaps we shall be told that here, 

 as in animals, there is a profound alternation concealed by apospory. 



All these complications are simply and easily avoided by remem- 

 bering what is almost universally forgotten and appears never to have 

 troubled Dr. Beard — that in spore-producing plants one must al- 

 ways distinguish between palingenetic spores and coenogenetic spores. 

 The palingenetic spore is seen at its simplest in Bacillus anthra- 

 cis for example. It is essentially a modified vegetative cell. It is 

 often the only type of spore present in a life-history. It is not a re- 

 sultant of a sexual process, but may occur in a life- history together 

 with the coenogenetic spore, as in Oedogonium. Here the filament or 

 gametophyte produces the palingenetic zoospore (gonidiura), which in 

 certain cases assumes the character of an androspore, while the syn- 

 gamete segments into four coenogenetic spores or carpospores' These 

 latter spores are always subsequent to a sexual process and are the 

 principal type in archegoniate plants*) and the only type in meta- 

 spermic plants. 



This is the type of spore that together with the tetragonidia 

 characterizes the Florideae. For further discussion of these points 

 see the paper cited below. 



It has always seemed to me that the proper interpretation and 

 connection of the facts of metazoan and metaphytic reproduction are 

 gained by considering the metaphytic coenogenetic spore 

 an homologue of the metazoan blastomere. This which is 

 a much more thinkable method of connecting the facts of reproduction 

 in the two kingdoms than that of Beard who postulates an undemon- 

 strated and I think undemonstrable antithetic alternation among 

 Metazoa is abundantly justified by the well-known results obtained by 

 experimental zooembryology. 



I will attempt to put this statement clearly. The syngamete of 

 the Metaphyte or of the Metazoan may develop in one of two ways 

 — directly into an organism like the parent or indirectly into a group 

 of isolated blastomeres, spores, or into a single spore-mother-cell or 



4) If the protonemal chlamydo spores of Funaria and the multiple 

 metanemal spores, commonly termed gemmae (but very diiferent from the 

 apical-cell-containing gemmae of Lunularia and Marchantia), of Tetraphis 

 and Aulacomnion are excluded from the category of spores it is proper 

 to say that all the spores of archegoniate plants are carpospores. 



5) Mac Millan, On the limitation of term "Spore". Botan. Gazette, 

 Apr. 1893. 



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