Taxonomic Notes on Myxomycetes, IV

Abstract

Lister (Mycetozoa ed. 3: 217. 1935) says of this species: "It is closely allied to Oligonema flavidum, of which it appears to be hardly more than a variety." Hagelstein (Mycologia 31: 341. 1939; 32: 377. 1940) notes its resemblance to A. nitens, from which it differs in its more golden color and the netted capillitium, in addition to the characteristic markings of the latter. Careful examination of a large number of collections of both 0. flavidum and 0. nitens and of a smaller but adequate number of collections of Calonema aureum failed to disclose any that I should regard as intermediate. In addition to the constant presence of a capillitial net, and the characteristic capillitial markings of the Calonema, both capillitium and sporangium wall turn a bright pinkish orange when a weak solution of potassium hydroxide is added to a mount, whereas the only effect of this solution on any Oligonema is to cause a slight intensification of the yellow-brown color of the sporangium wall.