DIDERMA 133 



16. DlDERMA COR-RUBRUM Macbr. 



N. A. Slime-Moulds ed. 2. 140. 1922. 

 1925. Diderma montanum Meylan ex Lister, Mycetozoa ed. 3. 83, in part. 



Sporangia gregarious, clustered, small, 0.5-0.7 mm., sessile, 

 corrugate-plicate, especially above, snow-white, the outer peridium 

 cartilaginous, polished without and within, the inner delicate, evanes- 

 cent; columella well developed, globose or clavate, anchored by several 

 stout transverse trabecular to the peridial wall, papillate, deep red as 

 is the peridium, especially below; capillitium very delicate, sparingly 

 branching, colorless; spores verruculose, fuliginous, tinged with red, 

 about 12 /x. 



This curious but elegant little species is represented by a single 

 colony collected by Professor Morton Peck on rotten wood in Iowa. 

 It resembles D. sauteri but is distinguished by the plicate white wall, 

 the stout columella with its lateral extensions, as by the more delicate 

 spores. Miss Lister includes it in D. montanum, from which the de- 

 scription would seem to exclude it. The type and only collection is 

 in the British Museum, but it is to be hoped that it will appear again 

 in the original locality. 



Iowa. 



17. Diderma trevelyani {Grev.) Fr. 



Syst. Myc. 3 : 105. 1829. 

 PL IX, Figs. 200, 201. 



1825. Leangium trevelyani Grev., Scot. Crypt. Fl. 132. 



1842. Polyschismium trevelyani (Grev.) Corda, Icon. Fung. 5 : 20. 



1875. Chondrioderma trevelyani (Grev.) Rost., Mon. 182. 



1875. Chondrioderma cerstedtii Rost., Mon. 184. 



1877. Diderma geasterodes Phill., Grev. 5 : 113. 



1877. Diderma laciniatum Phill., Grev. 5 : 113. 



1892. Chondrioderma geasteroides (Phill.) Massee, Mon. 201. 



Sporangia scattered, globose or nearly so, smooth or verruculose, 

 yellow-brown, reddish brown or rufescent, sessile or short-stipitate; 

 peridium firm, splitting more or less regularly into unequal, revolute, 

 petal-like lobes which are white within, composed of three layers, a 

 thin cartilaginous outer layer and a membranous inner layer, con- 

 nected by a thick calcareous middle layer composed of coarse, some- 

 what crystalline lime clusters, the outer layer often splitting to form 

 plates suggesting Lepidoderma; stipe, when present, equal, furrowed, 

 concolorous; columella small or none; capillitium abundant, the threads 

 rather rigid, purple or purplish brown, branching and anastomosing, 

 more or less beaded; spores dark, violaceous brown, spinulose, 11-14 ix. 



