PHY S A RUM 89 



Physarum, but in large masses involve portions of the net itself, nodes 

 and all, as in Leocarpus. Miss Lister's beautiful figures, op. cit., 

 Figs. 66 and 82, show this very well. 



In The Journal of Botany, 52, p. 100, the distinguished author 

 and artist records the discovery of this species in the mountains of 

 Switzerland. She says: "This specimen shows a striking resemblance 

 to Leocarpus fragilis Rost., both in the shape of the sporangia and in 

 the capillitium and spores; but although the color of the sporangia 

 varies in both these species, the walls of F. (L.) fulvum are mem- 

 branous and rugose with included deposits of lime granules and show 

 nothing of the polished cartilaginous layers characteristic of L. 

 fragilis." 



The species is a boundary type at best, and shows again how arti- 

 ficial all our taxonomy is apt to prove, when the number of presenta- 

 tions of some particular type becomes larger. 



For these reasons, the present author writes Physaru?n, and believes 

 the question of identity in a perplexing case fortunately settled. 



46. Physarum variabile Rex. 



1893. Physarum variabile Rex, Proc. Phil. Acad., p. 371. 



1911. Physarum variabile Rex, List, Mycetozoa, 2nd ed., p. 47. 



Sporangia scattered, stipitate, sub-stipitate or sessile, about 1 mm. 

 high; regularly or irregularly globose, ellipsoidal, obovate or cylin- 

 dric-clavate in shape ; sporangium wall sometimes apparently thick, of 

 a dingy yellow or brownish-ochre color, slightly rugulose on the sur- 

 face, crustaceous, brittle, rupturing irregularly, sometimes thin, trans- 

 lucent, covered externally with flat circular calcic-masses falling away 

 in patches; stipes nearly equal, occasionally much expanded at the 

 base, rough, longitudinally rugose, variable in size, sometimes one- 

 third of a millimetre high, sometimes a mere plasmodic thickening of 

 the base of the sporangium ; color of stipes varying from a yellowish- 

 white to a dull brownish-gray ; capillitium a small-meshed network of 

 delicate colorless tubules with large, many-angled, rounded masses of 

 white, or rarely yellowish-white lime-granules at the nodes; no true 

 columella, but often a central irregular mass of white lime-granules; 

 spores dark violet-brown, verruculose, 9-10 ix. 



