254 MONOGRAPH OF THE LABOULBENIACE^E. 



If, on the other hand, the group is compared with the ascomjcetous fungi, one 

 finds that the differences in general structure are apparent and not real, the vegeta- 

 tive body consisting of a septate filament which elongates and branches in a definite 

 fashion within a general enveloping membrane. The thallus is thus not essentially 

 different in the two cases, and the perithecium of the Laboulbeniaceas is exactly com- 

 parable to the corresponding structure in other Ascomycetes, like Sphoerotheca for 

 example ; the process of formation in either case involving the enclosure of a female 

 cell, through the upgrowth around it of filaments originating below its base. It is 

 further unquestionably true that its sexual organs and sexual reproduction are strictly 

 homologous with the corresponding structures and phenomena that have been 

 described in the Collemacese, in Ascobolus, in Sphcerotheca, and in other instances. 

 Lastly, the products resulting from this sexual process, the asci and ascospores, are 

 identical and homologous with those similarly resulting in the cases mentioned. 



That the Laboulbeniaceas greatly resemble the Floridece may then be inferred from 

 the general structure of its members, its sexual phenomena, and the development of 

 its sporocarps and asci, resemblances which, it may be added, are coupled with an 

 aquatic or sub-aquatic habit. That it belongs not among the algse, but among the 

 fungi, is indicated by the absence of chlorophyl and of true cellulose in its cells, 

 coupled with a parasitic habit; while the products of its sexual reproduction, the asci 

 and ascospores, are those of fungi and by no means of algse. 



In view of these facts the derivation of the Ascomycetes through the Laboul- 

 beniaceoe from some branch of the Floridese seems a supposition not unworthy consid- 

 eration, and although personally I regard such a suggestion as a mere speculation, 

 I must confess that if one must have a theory of derivation in this case on a basis of 

 ascertained facts, an origin of the nature above indicated is in my own opinion more 

 probable as well as more logical than that which is usually held : since the latter in- 

 volves the, to my mind, improbable assumption that a parasitically degraded series 

 has attained, by a parallel course of upward development, the same goal which has 

 been reached by the carposporic algae ; the alternative, on the other hand, involving 

 the consideration of the fungi as a heterogeneous group derived through degenera- 

 tion at different points from types already elaborated in the algal series. 



Speculations of this nature are, however, of little value in the absence of facts by 

 which they may be substantiated ; yet if the origin of the family from the Florideoa 

 is, to say the least, problematical, it is almost equally a matter of conjecture if one 

 attempts to determine their exact point of union with the Ascomycetes in general. 

 While their color, gelatinous consistency, and entomogenous habit might suggest a 



* 



