W. C. Sturgis — Type- Specimens of Myxoniycetes. 4*71 



description of Craterium citi'inelhim , List. It was distributed by 

 Rex in Ellis & Everhart's N. Amer. Fungi, No. 2490. Macbride 

 (1. e., p. 38) says, "Under the last name {P. citrinellum^ Pk.) the 

 species has been generally recognized in the United States and 

 distributed." It is satisfactory, then, to note that the specimens so 

 distributed are identical with Peck's type, with the unimportant 

 exceptions that in the latter the lime-knots of the capillitium are 

 rather smaller and the spores are smaller and decidedly less distinctly 

 spinulose than is the case in the specimens distributed by Rex. In 

 the type the spores measure 9.4-1 1.2/;, as compared with 11.5-12|u, 

 in the case of the Ellis and Everhart specimens. 



Peck originally called his specimen Dlderma citrinum, Fr., a 

 species referred by Rostafinski to Physariim Schumacher i, Spr. 

 (P. citrinum, Schum.). When Rostafinski's Monograph appeared 

 Peck changed the name of his specimen to Physarum citrinelhim, 

 Pk., and published a brief but sufficiently accurate description of it. 

 (Rep. N. Y. St. Mus., xxxi, p. 57.) The species is certainly very 

 closely related to at least one other. In 1818 Fries described his 

 Physarum flavxim. This was the same thing [teste Rostafinski, 

 Mon., p. 100) as a specimen which Fries had sent to Kunze during 

 the previous year under the name Physarum citrinella, Fr. This 

 earlier name Fries disregarded in later publications, and the final 

 form in which he left it was Craterium flavum, Fr. Rostafinski 

 adopted the earlier generic name, with the remark that " the ti'ansfer 

 of this Physarttm to the genus Craterium, as Fries did later, rests 

 on no sufficient grounds," Now the description of Physarum flavum, 

 Fr., distinctly recalls Peck's species. Lister's comment on the former 

 is : " This description applies to Craterium citrinellum, List.", and 

 R. E. Fries, in his latest work on the Swedish Myxomycetes,* com- 

 menting on P. Jfavum, Fr., recognizes its close relationship to C. citri- 

 nellum, List., though, not having seen a specimen of the latter, he is 

 naturally unwilling to unite the two and therefore retains the Fries- 

 ian name. Personally, I have little doubt that the two forms are one 

 and the same species, but. in default of comparative material, Peck's 

 name must be retained for the American form. Whether we should 

 call it a Physarum or should refer it to the genus Craterium because 

 of the cartilaginous character of the base of the sporangium wall, is a 

 comparatively unimportant matter of opinion. 



More important is Macbride's reference of the species to Physarum 

 ccespitosum, Schw. The original description of that species is brief, 



*Ofersigt af Kongl. Vetenskaps-Akad. Forhandl., 1899, No. 3, p. 224. 



