Notes and Brief Articles 



95 



A New Lichen from an Unusual Substratum 



Dung of various animals is examined frequently by mycologists 

 for fungi not found elsewhere, and algae and mosses are seen on 

 these substrata not infrequently. Among the fungi the lichenist 

 sometimes sees Cladoniae and Bacidia inundata, but I had not until 

 recently known of a lichen species found on no other substratum 

 than dung. 



For many years I have made it a practice to examine any dung 

 that was colored green by algae or by moss protonemata, in the 

 hope that I might find some new or rare lichen. Finally, on the 

 tenth of March, 1920, near Conway, Rockcastle County, in central 

 Kentucky, I found what appeared to be the minute fruits of some 

 lichen which had parasitized Protococcus growing over some cow 

 dung. These minute fruits were Botrydium-like in appearance, 

 and examination showed that they belonged to a lichen of the genus 

 Thelocarpon. 



Growing with the Thelocarpon was another ascomycete with 

 even more minute fruits, often giving the appearance of having 

 parasitized the algae, forming a true lichen thallus. The Thelo- 

 carpon, on the other hand, showed no superficial thallus and no 

 relationship with the algae other than that the fruits were rendered 

 yellow-green by a layer of the algae, which spread over their sur- 

 faces. This condition made it appear that the lichen thallus was 

 wholly within the substratum at the time when the fruits were 

 mature, though algae were in all probability parasitized and a 

 superficial thallus produced in early development, only to disappear 

 later. Several species of Thelocarpon have been described as hav- 

 ing no thalli, all of them probably having, in their early stages of 

 development, superficial thalli of one of the types found among 

 crustose lichens. In all of these instances it would be worth while 

 to trace out the relationship between the lichen and the algae, which 

 occur always in the thalloid veils of species of Thelocarpon, and 

 usually in crustose thalli as well. 



The description below was prepared after a careful examination 

 of the descriptions of the 30 known species of the genus. 



