The My.xomycctes of the Miami \'alle\\ Ohio. 149 



a thin membrane with an outer layer of minute, stellate 

 crystals of lime. Each sporangium traversed by a central 

 subcylindric hollow columella, which extends also to the 

 branches, but does not reach to their apices. Capillitium of 

 slender threads, more or less branched, and combined into a 

 network. Spores globose, violaceous. 



Spumaria is essentially related to Didymium by the crystals 

 of lime upon the walls of the sporangia. Rostafinski's figure 

 158 can only be regarded as ideal or diagrammatic. I am dis- 

 posed to question the existence of the central columella alto- 

 gether; if it does exist, it must be extremely defective. 



I. Spumaria alha. Bull. Plasmodium white, amplectant. 

 ^thalium variable in form and size, resting upon a white, 

 membranaceous hypothallus, and usually covered by a white, 

 friable, common cortex composed of minute crystals of lime. 

 The component sporangia elongated, irregular, more or less 

 branched, the branches rude, deformed, compressed, laterally 

 confluent, obtuse or pointed at the apex ; the walls of the 

 sporangia thin and delicate, rugulose, pellucid, with a tinge of 

 violet, iridescent when divested of the crystals of lime. Cap- 

 illitium of slender threads, more or less branched and com- 

 bined into a net; the threads dark colored, with pellucid 

 extremities, and furnished with occasional, rings or roundish 

 swellings throughout their length. Spores globose, densely 

 spinulose, dark violaceous, 10-14 mic. in diameter. Plate 

 XII, Fig. 43. 



Climbing up and surrounding the stems of small shrubs, 

 herbaceous plants, culms of grasses, etc., especially those of 

 living plants, rarel)'' effused upon old wood, bark, leaves, etc. 

 The sethalium from two or three to several centimeters in 

 length, and with a radial thickness of two or three to several 

 millimeters. The following forms or varieties have been dis- 

 tinguished as species at different times : 



Var. I. DIDYMIUM. Sporangia irregular, simple or lobed 

 and branched, lifted up on narrow, flat extensions of the 

 hypothallus, as if furnished with short white stipes ; the com- 

 mon cortex wanting. This '\s Didymiiun spicinarioides, Fr.; it is 

 probably a dwarf form of the next variety. Plate XII, Fig. 42. 



Var. 2. cornuta. ^5^thalium large and rugged in outline, 

 cinerous from the scanty cortex; the sporangia loosely ccm- 



