Perichaena 259 



capillitiuni a loose, inelastic network of cylindrical threads with 

 thickenings in the form of closely set warts. 



A SINGLE SPECIES. 



1. Lachnobolus congestus (Somm.) Lister, Mycetozoa ed. 2. 246. 

 1911. 



Physarum congestum Somm. Fl. Lapp. 241. 1826. 



Lachnobolus incarnatus Schroet. in Cohn, Krypt. Fl. Schles. 3 (1): 110. 1885. 



Plasmodium white or rosy (Lister). Sporangia subglobose, 

 sessile, clustered and heaped, 0.5 to 0.8 mm. diam., pale copper- 

 colored when fresh, fading rapidly to dull ochraceous; sporangial 

 wall membranous, firm, papillose, ochraceous or pinkish. Capilli- 

 tium a network of freely branching, flaccid, pinkish or ochraceous 

 threads, irregular in width varying from 2-8 n diam., closely and 

 equally studded with prominent warts, and attached at numerous 

 points to the sporangial wall. Spores pale pink in mass, fading 

 to ochraceous, faintly and minutely warted, with a few, scattered, 

 stronger warts, 6-8 n diam. 



Type locality: Norway. 



Habitat: On dead wood. 



Distribution: Colorado, *Iowa, New York, *Ohio, Ontario, 

 *Oregon. 



Illustration: Lister, Mycetozoa ed. 3. pi. 183. 



A very rare species which may be found, however, by careful 

 search. It forms small heaps of clustered sporangia which re- 

 semble Oligonema nitens in appearance but are dull ochraceous 

 in color. It appeared twice on old sugar-bags that were used to 

 cover young plants in my garden, and I have also collected it on 

 two other occasions. 



Genus 44. PERICHAENA Fries, Symb. Cast. 11. 1817. 



Sporangia subglobose or irregular, sessile or forming plasmo- 

 diocarps, rarely short-stalked ; sporangial wall usually of two 

 layers, the outer thickened with angular granules which are ex- 

 ceptionally absent in the upper part, the inner usually mem- 

 branous; capillitiuni of branching or simple, tubular, inelastic 

 threads, spinose, minutely warted, or nearly smooth, usually 

 marked with irregular constrictions; spores yellow or brown, 

 minutely warted. 



Type species : Perichaena populina Fries. 



