638 THE PHYLOGENY OF THE FUNGI 



and protected by a structure made up of vegetative hyphae (apothecium, 

 perithecium, etc.)- The same is true of the Florideae where the union of 

 one sperm cell with the trichogyne will bring about the formation of a 

 spore fruit (as Sachs called it) with many carpospores, either surrounded 

 by a protective envelop or not. It should be noted that in the very simple 

 Endomycetaceae and Saccharomycetaceae, considered by the author to 

 be extreme simplifications from very complex ancestors, a single ascus is 

 produced by each sexual act. The proponents of the hypothesis that the 

 Ascomyceteae have arisen directly from the Phycomyceteae naturally 

 consider the foregoing fungi to represent connecting hnks between the 



two groups. 



A further argument against the phycomycetous origin of the Asco- 

 myceteae is the type of mycelium, which is prevaihngly coenocytic in the 

 former and cellular in the latter. To be sure cross walls occur frequently 

 in some Phycomyceteae but they are mainly (1) to set off reproductive 

 organs from the main mycelium, (2) to fence off emptied portions of the 

 mycelium from those regions in which living protoplasm is still present, 

 and (3) to wall off injured regions. Furthermore the production of the 

 septa in the coenocyte is entirely independent of any immediately pre- 

 ceding nuclear division. In the higher fungi the mycelium is usually 

 cellular and the cell walls separate uninucleate or binucleate cells. Cell 

 division and septum formation are the immediate consequences of the 

 division of the nucleus or of the two nuclei of the cell. It cannot be denied 

 that the mycelium of many Ascomyceteae is composed of coenocytic seg- 

 ments separated by cross walls, but these forms are relatively few in 

 number. On the other hand the somewhat anomalous Basidioholus in the 

 Entomophthoraceae has its mycelium made up of uninucleate cells. 



If we accept Sachs's suggestion as to the possible origin of Asco- 

 myceteae from the Florideae we must prepare a phylogenetic tree that 

 will include as more primitive those forms whose characters include the 

 greater number of those found in the Florideae. Therefore we must give 

 first place to those families or orders in w^hich receptive hyphae (tricho- 

 gynes) are fertilized by nonmotile, naked or thin-walled, usually endog- 

 enously produced sperms and from whose oogones arise several or many 

 asci or ascogenous hyphae bearing the asci. Thus we should place first in 

 the Ascomyceteae the Laboulbeniales, Lecanorales, Sphaeriales, and some 

 Pezizales, granting that many of the last two orders accomplish their 

 sexual reproduction by direct contact of the antherids with trichogynes 

 or oogones. All of these forms are rather complex in their structure, far 

 more so than the very simple yeasts and Taphrinales, which are placed at 

 the base of the class by so many mycologists. On the same grounds 

 of reasoning the Uredinales also, must be considered to proceed from 

 near the orders believed by the author to be primitive in the Asco- 



