58 THE NORTH AMERICAN SLIME-MOULDS 



1837. Didymitim gyrocephalum Mont., I.e. 



1875. PJiysarum polymorpJium (Mont.) Rost., Man., p. 107. 



1875. Tilmadoche gyrocephala (Mont.) Rost., Man., p. 131. 



Sporangia spherical or irregular, impressed, gyrose-conflu- 

 ent, helvelloid, umbilicate below ; peridium thin, ashy, covered 

 with evanescent yellow squamules, fragile ; stipe from an ex- 

 panded membranaceous base, long-subulate, yellow ; spores 

 smooth, violet, 9-11 /JL. 



A most singular species and well defined is this, occurring in 

 masses of decaying leaves or in rotten logs. The plasmodium 

 at first colorless ; as it emerges for fructification, white, then 

 yellow, spreading far over all adjacent objects, not sparing the 

 leaves and flowers of living plants ; at evening slime, spreading, 

 streaming, changing; by morning fruit, a thousand stalked 

 sporangia with their strangely convoluted sculpture. The even- 

 ing winds again bear off the sooty spores, and naught remains 

 but twisted yellow stems crowned with a pencil of tufted silken 

 hairs. August. 



Although Rostafinski's description of this species is accurate 

 and marks exactly a TilmadocJie and is very different from his 

 description of PJiysarum polymorpkum, nevertheless it is prob- 

 able that both descriptions have reference to the same thing. 

 All specimens on which both species were based were American; 

 P. polymorpJium, North American. But the only North Ameri- 

 can form to which reference can be made is that by Schweinitz, 

 called P. polycepJialum and, fortunately, sufficiently described. 

 Furthermore, Rostafinski, under T. gyracepJiala, himself affirms 

 the probable identity of Montagne's Didymium gyrocephalum 

 with the Schweinitzian species, and uses Montagne's specific 

 name provisionally. For these reasons it seems proper to write 

 the species as above. 



Widely distributed and common, from Maine and Canada to 

 Nebraska, and Washington and south to Nicaragua. 



2. TILMADOCHE ALBA (Bull.} Macbr. 



1791. Spharocarpus albus Bulliard, Champ., p. 137, t. 407, Fig. 3, and 

 t. 470, Fig. i, A-G. 



