180 THE NORTH AMERICAN SLIME-MOULDS 



A. DIANEME^E. 

 A single genus, 



Dianema Rex. 



1891. Dianema Rex, Proc. Phil. Acad., p. 397. 



Sporangia simple or plasmodiocarpous ; capillitium composed 

 of threads without characteristic thickenings running entirely 

 across the sporangium attached both to the base and to the 

 opposite wall, not joined to form a network. A single species 

 in our limits, 



i. DIANEMA HARVEYI Rex. 



1891. Dianema harveyi Rex, Proc. Phil. Acad., p. 397. 



Sporangia gregarious, generally rounded or cushion-shaped, 

 depressed, sessile, iridescent bronze, I mm. in diameter; peridium 

 thin, translucent, opening irregularly ; capillitium of simple 

 threads, not netted, but often forked two or three times, taut, 

 running from base to the top of the sporangium, ochraceous ; 

 spores in mass brownish yellow, by transmitted light pale yel- 

 lowish, minutely roughened, 8-10 /u.. 



This interesting species was collected in Orono, Maine, in 

 1889, by Professor F. L. Harvey, and so far as can be learned 

 has not been taken since. Mr. Lister records two species from 

 England which he refers to this genus. As to its systematic 

 place, Dr. Rex says, I.e. : " It stands as a single representative 

 of a new and separate family adjoining the Perichaenacece in the 

 order Calonemecs of Rostafinski." 



Rare. Maine. 



B. 



Key to the Genera of the Perichsneae. 



A. Sporangia more or less plasmodiocarpous in type, terete; dehiscence 

 irregular ........ I. OPHIOTHECA 



B. Sporangia more or less polygonal in outline, or round, depressed ; dehis- 

 cence circumscissile .... .2. PERICH/ENA 



