140 THE MYXOMYCETES 



Wilczekia evelin^: Meylan 



Bull. Soc. Vaud. Sc. Nat. 56 : 69. 1925. 



Sporangia sessile, ovoid or elliptical, rarely subspherical, often 

 compressed transversely, 0.3-0.5 mm. tall, dull gray, somewhat rugu- 

 lose or furrowed, darker or brownish below, usually grouped in twos 

 or threes; peridium membranous, single, the entire surface covered 

 with brownish plasmodic particles, and irregular or more or less star- 

 like calcareous granules 2-4 \x in diameter; capillitium of branched, 

 anastomosing filaments, similar to those of Didymium, of the same 

 color as the spores except at the extremities, which are hyaline, so 

 that the surface of the capillitial mass is grayish, the forkings forming 

 triangular enlargements sometimes containing the same materials as 

 those deposited on the peridium; columella usually lacking, sometimes 

 well developed and then calcareous; spores sooty, dull, scarcely trans- 

 parent, spiny, 9-11 (x. 



The dehiscence is irregular, by the fragmentation of the upper part 

 of the peridium, the capillitium, which adheres to the peridium only 

 at the base, retaining its shape as in some species of Physarum. The 

 author speaks of "amorphous crystals" of lime, and later of "calca- 

 reous crystals of irregular form or star-shaped or granular." The infer- 

 ence is that they are not regularly star-shaped, as in Didymium. 



Jura Mountains, Switzerland. 



6. Lepidoderma de Bary 

 in Rost. Versuch 13. 1873. 



Sporangia stalked, sessile or plasmodiocarpous; peridium cartilagi- 

 nous, more or less covered with large calcareous scales which are 

 either superficial or immersed in lenticular cavities; capillitium non- 

 calcareous. 



The crystalline scales are soluble in weak hydrochloric acid, and are 

 enclosed in a delicate sac. Could the outer peridium be seen in process 

 of formation it would probably be found to be made up of an ecto- 

 sarcous foam in whose cavities the excreted calcium is crystal- 

 lized. 



The taxonomy of this small genus is difficult. L. tigrinum, the com- 

 monest species, is rather clearly marked, but descriptions of the other 

 species are not in agreement, and sometimes specimens distributed 

 by those who have published on them are not in entire accord with 

 the descriptions. The following treatment is based on a careful 

 comparison of the material available with the published descrip- 

 tions. 



