22 THE NORTH AMERICAN SLIME-MOULDS 



b. Peridium calcareous, more or less throughout. 



i. Capillitium calcareous throughout . . 4. BADHAMIA 

 ii. Capillitium in part hyaline. 



* Sporangium vase-like or more or less tubular, 

 f Opening irregularly, the wall with inwardly projecting 

 calcareous spines . . . -5- PHYSARELLA 

 ft Opening by a lid or with dehiscence more or less 

 plainly circumscissile ... 6. CRATERIUM 

 ** Sporangia various, dehiscence irregular, 

 f Capillitium evenly branched ; the calcareous nodes 

 small, fusiform . . . .3. TILMADOCHE 

 ft Capillitium intricate ... 2. PHYSARUM 



1. FuligO (Haller) Pers. 



1753. Mucor Linn., Sp. PL II., No. 1656. (?) 



1768. FuligO Haller, Hist. Helv., Nos. 1233-1235 (in part). 



1801. Fuligo Haller, Pers. Syu., p. 159. 



Sporangia undefined, obscure, woven in and out among 

 each other to form a large cushion-shaped, aethalioid mass. 

 The outermost layer without spores, calcareous, forming a thick 

 but fragile crust. The middle layer spore-bearing, provided 

 with a calcigerous Capillitium. The lowermost layer developed 

 as a membranous hypothallus. 



Three species of Fuligo have in the United States been recog- 

 nized. In deference to the opinions of fellow-mycologists 

 three descriptions are here offered. It seems probable that all 

 are but varieties of the old form so long recognized in Europe. 

 Persoon tried (Syn. Metk., pp. 159-162) to establish several 

 species. Fries endeavored to follow him (Syst. Myc., III., p. 

 93): "In plures species cum Persoonio divellere Sommerfelt, 

 Greville et ipse fnistra conati sumus." 



Key to the Species of Fuligo. 



A. ^Ethalium small, i cm. or less . . . . 2. F. muscorum 



B. ^thalium large. 



a. Spores pale by transmitted light . . i. F. oimta 



b. Spores by transmitted light, violet-tinted . 3. F. I'iolacea 



