112 THE NORTH AMERICAN SLLME-MOULDS 



of two ?) a peculiar plexus which embraces several large cysts 

 or vesicles whose function or further homology does not readily 

 appear. 



From the base of the fructification rise also ascending 

 branches which are black, terete, and not infrequently branched 

 as if to form the capillitium of a Stemonitis. These ascending 

 branches are in many cases, probably in all, real, though as yet 

 imperfectly'developed, columellae. They rise, at least in many 

 cases, directly from the hypothallus, each is central to an 

 individual sporangium, rises to about two-thirds its height, but 

 never attains the summit. The sporangia are so crowded that 

 many are choked off below, never reach the top of the astha- 

 lium. In such cases the columella may cease at the sporan- 

 gium-top. The columella bears cystiferous threads sparingly, 

 if at all ; nevertheless these abound in the peripheral portions 

 of the sporangium all the way up, and are especially noticeable 

 beyond the level of the top of the columella. Many are so 

 arranged that the plexus with its vesicles occupies a place in 

 the plane separating adjacent sporangia, suggesting the possi- 

 bility that we have here to do with an imperfectly developed 

 surface-net and peridium. In this view the cysts would repre- 

 sent the meeting-point of two opposite radial capillitial threads 

 rather than the middle of one. This accords with Rostafinski's 

 observations and drawings. The cysts, then, belong morpho- 

 logically to the peridium or sporangium wall. It is a Stemoni- 

 tis whose sporangia have never been perfectly differentiated, 

 a case of arrested development. See further under Stemonitis 

 conflucns. 



Rostafinski really offers the first definitive description. Fries 

 probably distinguished it, but his description would not indicate 

 the fact except for the added note wherein appears the reason 

 for discarding an apparently older name, viz., that given by 

 Link. But neither Link nor Sowerby distinguished by descrip- 

 tion or figure Brcfeldia from Amaurochcete. 



Apparently not very common. New England, Wisconsin, 

 Minnesota, Iowa. 



