DiDERMA 99 



referred to the various editions of the Lister and Macbride 

 monographs for further particulars. 



7. Diderma alpinum Meylan, Bull. Soc. Vaud. Sc. Nat. 51: 261. 



1917. (N. Y. B. G. nos. 7171, 8774, authentic material.) 



Plasmodium white (Meylan). Sporangia crowded, sessile, 

 white, hemispherical or subglobose, or lengthened more or less 

 and confluent, 0.8 to 2 mm. diam., or forming long plasmodiocarps 

 up to 12 mm. or more long, seated on a white hypothallus; outer 

 layer of the sporangial wall smooth, shell-like, separating freely 

 from the membranous inner one. Columella large, convex, 

 rugged, together with the base of the sporangium yellow or flesh- 

 colored. Capillitium of rather stout, colorless or purplish threads, 

 branching or anastomosing, straight or flexuose. Spores brown- 

 ish purple, distinctly spinulose, 10-12 n diam. 



Type locality: Switzerland. 



Habitat: On herbaceous stems, etc. 



Distribution: *California. 



Illustration: None published? 



Closely related to D. globosum, the species difTers practically 

 only in the larger, more robust sporangia and plasmodiocarps. 



8. Diderma niveum (Rost.) Macbr. N. A. Slime-Moulds 100. 



1899. 



Chondrioderma niveum Rost. Mon. 170. 1874. 



Diderma albescens Phill. Grevillea 5: 114. 1877. (N. Y. B. G. no. 5636, type 

 material.) 



Plasmodium white (Lister). Sporangia crowded, subglobose 

 or hemispherical, sessile, 0.7 to 1.8 mm. diam., smooth, white, 

 sometimes seated on a white hypothallus; sporangial wall of two 

 layers, the outer densely charged with white lime-granules, sepa- 

 rating from the more persistent inner layer, which is membranous 

 and often iridescent and veined with scanty deposits of lime 

 above, cartilaginous and orange below. Columella large, convex 

 or hemispherical, orange or buff. Capillitium of branching and 

 anastomosing rather stout, purple threads, with pale extremities, 

 sometimes intermixed with more delicate threads, often beaded 

 with wart-like thickenings. Spores purple-brown, minutely spin- 

 ulose, 9-13 11 diam. (Plate 9, fig. 2.) 



Type locality: France. 



