MYCOLOGIA 



Vol. IX November, 191 7 No. 6 



NOTES ON NEW OR RARE MYXOMYCETES 



W. C. Sturgis 

 (With Plates 14 and 15) 



During the past few years a number of interesting species of 

 Myxomycetes have come to my attention. They are principally 

 the result of my own collecting, but in some cases they are 

 gatherings submitted to me through the courtesy of other col- 

 lectors. In the former case most of the gatherings were made 

 in Colorado, and add considerably to the already rich list of 

 Myxomycetes recorded from that locality. As usual, I am greatly 

 indebted to the expert judgment of Miss G. Lister and Professor 

 T. H. Macbride, to whom have been submitted the more critical 

 specimens included in the following list. 



Physarum melanospermum sp. nov. PI. 14, f. Plasmo- 

 dium? Sporangia stalked, gregarious or scattered, turbinate or 

 discoid, usually umbilicate above, 0.4-0.7 mm. in diameter, 

 grayish- white, rugose; sporangium- wall membranous, roughened 

 above with abundant deposits of white lime, darker and reddish- 

 brown where it merges into the stalk. Stalk stout, black, fur- 

 rowed, expanding below, about 0.2 mm. long and 0.1 mm. thick. 

 Capillitium consisting of abundant rounded, elongate or angular, 

 white lime-knots, connected by many delicate hyaline threads. 

 Spores dark-purplish-brown, closely spinulose, showing a paler 

 and smoother germinal area, 12. 5-16 /x in diameter. 



Habitat: On dead twigs and leaves of Clematis, Symphori- 

 carpos, etc., Aurora, Colorado (Bethel), Colorado Springs, Colo- 

 rado (Sturgis). 



This species has occurred abundantly in successive years on 

 fallen refuse under shrubby thickets. It somewhat resembles 



[Mycologia for September (9 : 257-322) was issued September 24, 1917.] 



323 



