IIOTSON. — CULTURE STUDIES OF FUNGI. 2G3 



cillium ngaricinuinjAuk, \:ir. cldvisi'dum (Mich. IT, ]). 577) is asso- 

 ciiited with it. 



A hirjjo number of spocimens of Geoglossuiii, with pU-nty of Sphaj^- 

 luiin and leaf mould about each, were collected — some infected, 

 others not — and were grown under bell jars or in a large germinating 

 vessel with a glass toj^. It was thus kept growing for nearly two 

 months, until it could be determined whether the Papulospora would 

 grow as a saprophyte on artificial media. A numl)er of tube cultures 

 were made of the bull)ils on various kinds of media, the most success- 

 ful of which were the ascoma of Geoglossum itself. About a dozen 

 large specimens of these with long stalks were selected and each put 

 in a test-tube which liatl prcN'iously been supplied with about half 

 an inch agar. These were then sterilized in an autoclave, the object 

 of the agar being simply to hold the specimen in place and thus lessen 

 the chances of contamination in making the transfers, etc. On this 

 medium a pure culture was eventuall}' obtained, which was then 

 transferred to other media such as potato, corn meal, chestnut, 

 horse dung, etc., hardened with agar. This fungus grows fairly well 

 as a saprophyte, better on hard than on soft media such as potato 

 and bran, but very slowly on horse dung, on which, after a month, 

 it had not grown much more than an inch from the point of inocula- 

 tion. Associated with the Papulospora on the ascoma were found, 

 among other fungi, specimens of Pleunuje anscrina (Rabh) Kuntze 

 and ]'crticillium aciaricinum Link, the latter producing in pure cul- 

 tures very large and conspicuous, l)rownish sclerotia. 



On its natural host Papulospora Candida forms conspicuous white 

 blotches spreading o\er the upper portion of the ascoma (Figure 47, 

 Plate 4), and if not too wet, extending down the stem. Although the 

 host is usually found in damp sphagnum swamps, the parasite is 

 largely confined to those specimens that grow tall, so that their tops 

 are comparatively dry. The mycelium is white, procumbent, branch- 

 ing copiously, but soon becoming indistinguishable as such, even with 

 a good hand lens, mainly on account of the large number of bulljils 

 that are formed which give the whole fungus a powdery appearance. 

 When examined under a microscope the mycelium is opalescent, 

 owing to the presence of numerous oil globules (Figures 42, 44, Plate 4) 

 and other colorless material in the cells. The cultures become com- 

 pletely covered with the white powdery bidbils which a little later 

 assume a characteristic cream color. 



The bulbils. — During the process of development of the bulbil a 

 short lateral branch divides up into a number of cells and the end 



