140 



THE ASCOMYCETES 



present treatment the 2 orders are retained; and the Endomyce- 

 tales are considered to consist of 3 families, the Taphrinales of 

 one family. 



EXDOAIYCETALES 



The Order Endomvcetales, accordingly, may for convenience 

 be divided as follows: 



1. Spore sacs manv-spored; gametangia plurinucleate Ascoideaceae 



1. Spore sacs with 8 or fewer spores; gametangia uninucleate 2 



2. Mycelium well developed Endomycetaceae 



2. Mycelium lacking or scantily developed Saccharomycetaceae 



Ascoideaceae. The Ascoideaceae are a small family whose 

 main interest to the mycologist centers around the fact that they 



Fig. 45. Dipodasciis albidiis. A. Two lateral hyphal branches, the one an 

 oogonium, the other an antheridium. Each is multinucleate. B. The 

 hyphal branches have fused apically, and the sporangium-like ascus has 

 started to form. C. Later stage in ascus formation. D. Tip of mature 

 sporangium-like ascus. (Adapted from Juel.) 



may constitute a link bet^veen the Phycomycetes and Euascomy- 

 cetes. The best-known members are Ascoidea rubescens, Sper- 

 viophthora gossypii, and Dipodasciis albidiis. Ascoidea rubescens, 

 originally collected in the slime flux of felled beeches, was first 

 studied comprehensively by Brefeld (1891) and more recently 

 by Walker (1931, 1935), who found it in slime flux of elm. Its 

 mycelium is coenocytic but septate and branched. It forms tufts 



