Sturgis : New or Rare Myxomycetes 



325 



Physarum sulphureum Albert. & Schw. Syn. P. variabile 

 Rex. During the summer of 191 4 a species of Physarum oc- 

 curred abundantly on dead twigs and leaves in a swamp in the 

 Wet Mountain Valley, Colorado. Some of the gatherings showed 

 the greenish or bronze-yellow, globose or somewhat clavate 

 sporangia, and the reddish-brown, densely calcareous stalks of 

 P. variabile. Others agreed perfectly with the original descrip- 

 tion and figure of P. sulphureum. This led to a careful study of 

 the two, with the result that it proved impossible to discover 

 any essential differences between them. The points of difference 

 noted by the Listers (Mon. Mycet., Ed. 2, pp. 46-47) emphasize 

 the marked similarity. Macbride (N. A. Slime-Moulds, pp. 39- 

 40) gives an admirable description of P. variabile — though plac- 

 ing it among the forms with non-calcareous stalks — but makes 

 no mention of P. sulphureum. In a recent letter, Miss Lister 

 states that in her opinion the Colorado gatherings prove the 

 identity of the two so-called species, and at the same time she 

 calls my attention to a minor point of similarity between them in 

 the form of small, greenish, spherical bodies which become ap- 

 parent in the wall and lime-knots, after the lime is dissolved out 

 with acid. In the Colorado material sessile and plasmodiocarp 

 forms frequently occur. 



Physarum carneum List, and Stur. This rare species, first 

 described from material collected near Colorado Springs in 1908, 

 was found again in the Wet Mountain Valley, Colorado, in 

 August, 1 914. It is satisfactory to note that this second gather- 

 ing, occurring many miles from the original locality, wholly 

 confirms the original diagnosis in the tawny sporangia borne on 

 delicate, buff, limeless stalks ; large, branching, white lime-knots ; 

 and bright-brownish-purple, spinulose spores, paler and smoother 

 on one side. The original gathering was on decayed wood, the 

 later one on a dry Basidiomycetous fungus. 



Physarum fulvum (Macbr.) List. This species has hereto- 

 fore been represented with certainty by only the single gathering 

 made by Mr. Bethel, of Denver, in Loveland Pass, Colorado, in 

 1896. This occurred on living willow at the edge of melting 

 snow. In August, 191 5, I found it growing in limited quantity 

 on dead coniferous wood near Lake Eldora, Colorado. Notwith- 



