46 



Mycologia 



My thanks are due to Dr. N. L. Britton, of the New York 

 Botanical Garden, for permission to examine the collection in the 

 herbarium, and to Mr. Sydney Prentice, of Pittsburgh, for assist- 

 ance in making the drawings. The kind assistance of other 

 persons is acknowledged in the proper place under the discussion 

 of different species. 



Rhinotrichum Corda, Ic. Fung, i : 17. 1837 

 Physospora Fries, Summa Veg. Scand. 495. 1849. 



Type species, Sporotrichum rubiginosum Fries. 



Original description : Flocci erecti, septati, supra verrucosi ; 

 sporis simplicibus verrucis innatis, dein deciduis et hylo instructis. 

 Fries describes the genus Physospora as follows : Flocci caespi- 

 tosi, septati, persistentes, demum laxi, sporis vesiculosis, simplici- 

 bus, e floccorum verrucis enatis adspersi. 



Type species, Rhinotrichum simplex Corda. 



Saprophytic or parasitic (?) ; mycelium creeping, septate, intri- 

 cately interwoven, forming a loose or sometimes rather dense 

 stratum ; fertile branches erect or suberect, simple or branched ; 

 spores simple, colorless or slightly colored, borne on spicules (ster- 

 igmata) on the ultimate divisions (basidia) of the fertile branches. 



Rhinotrichum canescens Speg., parasitic on leaves, has been 

 reported from Paraguay. If this is a true Rhinotrichum it is 

 the only parasitic species known. All other known species grow 

 on decaying wood or stems, usually on the under side. 



The genus Physospora is not necessary, as the species under it 

 may well be included under the genus Rhinotrichum as defined 

 above. The difference lies chiefly in the swollen divisions of the 

 fertile branches of the former. But all branches are not swollen, 

 some are attenuated as in some species of Rhinotrichum. 



Either Physospora must be reduced to synonymy or else the 

 species R. Curtisii and R. ramosissimum must be transferred to 

 Physospora. The differences in this case are not sufficient to 

 justify two distinct genera. 



The genera Rhinotrichum and Botrytis are somewhat related. 

 In the latter the spores are clustered at the tips of the fertile 

 branches, while in the former the spores are more or less scat- 

 tered on the ultimate division or divisions of the fertile branches. 



