Pound: REVISION OF MUCORACEAE. 89 



Sub-family 2. Mortierelleae. 



Sub-family 3. Choanephoreae. 



Sub-family 4. Chaetocladieae. 



Sub family 5. Cephalidieae. 



Like all sequences, this one is open to the objection that it 

 separates related forms and places unrelated ones in juxtaposi- 

 tion. No lineal arrangement is possible which will not do this 

 more or less. Juxtaposition can only partially represent 

 relationship in a lineal disposition. 



The relationship of the several groups may be indicated by 

 the following diagram: 



\ I 

 N Mortierelleae. Eumucoreae. Piloboleae. 



V f Bhizoiieae. 



Thamnidieae. 



9 I 



V ' ? Choanephoreae. 



\ I 



Cephalicleae. Chaetocladieae. 



There can be no doubt, as M. Dewevre points out, that the 

 Mucoreae are the pivotal group from which the other groups 

 are to be derived. The conidia, which characterize the 

 Choanephoreae and Chaetocladieae, are evidently but reduced 

 sporangia, and Thamnidium links them with Mucor, which 

 indeed sometimes produces sporangiola under proper condi- 

 tions. The one possible exception is the Cephalideae. Their 

 connection with the rest of the group admits of some doubt, 

 Schroeter appears to think that the chains of conidia formed 

 by simultaneous division, which characterize this sub family, 

 are to be regarded as sporangia. But the analogy is somewhat 

 obscure. Von Tavel^ remarks the absence of anything cor- 

 responding to the sterile side branches or separate sporangio- 

 phores, and says significantly: '' Auch hier errinnert nichts * 

 * * * mehr an die sporangien.'" 



If the Cephalideae are derived from the Mucoreae, it is proba- 

 bly through the Mortierelleae, with which they have some points 

 of resemblance, especially the anastomosing aerial mycelium. 

 In this view, we may regard the conidiophores as equivalent to 

 the fertile mycelium of the latter, and the several conidia chains 

 as each representing a sporangium. The septa formed in the 

 conidiophores of Piptocephalis may tend to confirm this, but it 



3. Von Tavel: Vergleich. Morphol. 37. 



