140 Mycetozoa of North America 



refuse matter, the inner layer membranous. Capillitium a net- 

 work of purplish threads without lime-knots. 



A SINGLE SPECIES. 



1. Colloderma oculatum (Lipp.) G. Lister, Jour. Bot. 48: 312. 

 1910. 



Didymiiim oculatum Lipp. Verh. Zool.-Bot. Ges. Wien 44 (Abh.): 72. 1894. 



Plasmodium purplish brown (Lister). Sporangia scattered or 

 grouped in small clusters, sessile, rarely stalked, either subglobose, 

 0.3 to 1 mm. diam., or forming straight or curved plasmodiocarps 

 1 to 3 mm. long, olivaceous or purplish brown, glossy, sometimes 

 seated on a brownish purple hypothallus; sporangial wall of two 

 layers; outer layer, when moist, thick, gelatinous, hyaline, more 

 or less encrusted with yellowish olive, granular, refuse matter; 

 inner layer colorless, membranous, firm; the outer layer, on dry- 

 ing, retreats to the base, when the sporangia appear shining, 

 iridescent blue or violet. Stalk when present, short, stout, dark 

 brown. Columella absent. Capillitium persistent, consisting of 

 branching, anastomosing, pale or dark purplish brown threads, 

 colorless at the extremities, rising from the flat base of the sporan- 

 gium, 2-4 n thick below, very slender towards the surface, often 

 with a jointed appearance. Spores purplish gray, distinctly spin- 

 ulose, 11-15 ju diam. 



Type locality: Austria. 



Habitat: On dead wood among mosses and lichens. 



Distribution: New Hampshire, *Oregon, Pennsylvania, 

 *Vermont. 



Illustration: Lister, Mycetozoa ed. 3. pi. 214. 



A curious species. The sporangium is invested with an outer, 

 hyaline, gelatinous sheath, which covers it partly when wet, and 

 gives the form an eye-like appearance. The sheath retracts to 

 the base on drying, but will expand again if wetted. The species 

 has been rarely collected in North America, due undoubtedly to 

 its scattered, concealed habit of developing among mosses and 

 lichens, so that the sporangia cannot be noticed in the field. 



Family H. STEMONITIDACEAE 



Sporangia stalked; sporangial wall a delicate membrane, often 

 evanescent; stalk solid, at least in the upper part, usually extend- 

 ing within the sporangium as a columella from which the branch- 



