The 3fyxomyce/es of the ISHavii Valley, Ohio. 23 



2. Calonidia. CapilHtiuni of slender tul)ules, arising from 

 the base of the sporangium ; the surface traversed by a system 

 of branching veins. 



3. Triciiia. Capillitium consisting of numerous short 

 slender tubules, called elaters, which are wholly free ; the 

 spiral ridges parallel and conspicuous. 



4. Oligoxema. Capillitium scant}', composed of elaters 

 habituall}' irregular and abnormal ; the surface variously 

 marked. 



I. HEMIARCYRIA, Fr. Sporangia regular and stipitate, 

 rarely plasmodiocarp, the wall at maturity breaking away 

 from above downward, leaving more or less of the lower por- 

 tion persistent. Stipe more or less elongated, rarely wanting, 

 resting on a thin hypothallus. Capillitium of long slender 

 tubules, more or less branched, arising from the base of the 

 sporangium, or issuing from the interior of the stipe ; the 

 spiral ridges parallel and conspicuous, 3-5, rarely more in 

 number, smooth or spinulose. Spores globose, red, yellow. 



The genus is related on the one hand to Arcyria by the 

 mode of attachment of the threads, on the other hand to 

 Trichia, by the parallel spiral ridges which wind around them. 

 By the mode of branching of the threads, the species fall 

 readily into two sections. 



^i. Arcvrioides. Capillitium of slender threads, branch- 

 ing and anastomosing, thus forming a more or less evident 

 network. 



In some of the species the large irregular meshes of the 

 network are scarcely to be discerned, but are rather to be 

 inferred from the abundant branching of the threads and the 

 paucit}' of the free extremities. 



I. Hemiarcvria plumosa, Morgan, n. sp. Sporangium 

 obovoid to turbinate, olive-yellow to olive-brown in color, 

 stipitate; the wall densel}- granulose within, externally 

 smooth and shining, the upper part soon disappearing, leaving 

 a funnel-shaped persistent base. vStipe long, erect, reddish- 

 brown, arising from a thin hypothallus. Capillitium of 

 threads 5-7 mic. in thickness, repeatedly branched and anasto- 

 mosing, to form a dense network without any free extremities, 



