PRIMARY GROUPS OF FUNGI 235 



secondary spore or sporidium to the rank of a spore proper. 

 The second group composing the Basidiomycetes, the 

 Autobasidiomycetes, is derived from the Tilletiae, and, 

 like the latter, has the basidium aseptate or one-celled, 

 and bearing a definite number of spores at its apex, usually 

 four. It will be observed that the one point of difference 

 between the Hemibasidii and the Basidiomycetes consists 

 in the promycelium in the first-named group bearing a 

 variable number of secondary spores or sporidia, whereas 

 in the last-named group the promycelium (now a basidium) 

 bears a definite number of sporidia (now termed spores). 



The above brief review of Brefeld's scheme of classifica- 

 tion indicates very clearly that, from his point of view, 

 morphological features are alone of value in indicating 

 descent, and that if the sexuality theory was eliminated, his 

 system would not be in any way interfered with. 



This arrangement of the larger groups is, I consider, the 

 most satisfactory, from a morphological standpoint, that 

 has up to the present been submitted, and, with minor 

 modifications, will be adopted in the systematic portion of 

 this work. 



The most important departure from Brefeld's scheme 

 consists in the inclusion in the Hemiasci of all families 

 having the perithecium absent or comparatively rudimen- 

 tary, as Gymnoasceae, the genera Exoascus, Taphrina, 

 etc. Thekbolus returns to the Discomycetes, in the family 

 Ascobolaceae ; the reason for this change has already been 

 given. Consequently Brefeld's Carpohemiasci section of 

 the Hemiasci, based entirely on the genus Thekbolus, ceases 

 to exist. 



Brefeld, Unters. d. Mykol., Heft 1-13 (1872-1905). 



