282 RESEARCHES ON FUNGI 



carotin reaction, i.e. they turn blue ; and, with iodine dissolved in 

 potassium iodide, they turn blue-green. ^ The pigmented oil-drops 

 of C. scutellata are contained in large numbers in the protoplasm of 

 the cells making up the paraphyses and subhymenium. The pig- 

 ment was obtained by Zopf ^ by extracting with alcohol and forming 

 an ester with caustic soda. The ester, when treated with petrol- 

 ether, yielded a yellow substance that, after being dried, turned 

 blue when moistened with nitric acid. When examined spectro- 

 scopically by Bachmann,^ the pigment gave two absorption bands 

 like those of the lipochrome of the Uredineae. 



The Heliotropism of the Asci of Ciliaria scutellata. — Since the 

 disc of Ciliaria scutellata is flat or almost so, it is not difficult to 

 make heliotropic experiments with its asci. All that is required is 

 to let the fruit-body develop on the top of a board lying on the 

 ground in unilateral light and then, by microscopical investigation, 

 to find out whether or not the tops of the ripe asci have become 

 curved toward the source of illumination. 



The conditions for such a heliotropic experiment as that just 

 suggested were provided by one of the ice-houses of the Arctic Ice 

 Company of Winnipeg. This Company, not far from Winnipeg on 

 the banks of the Red River, has a series of large wooden ice-houses 

 each of which is 100 feet long, 30 feet wide, and about 50 feet high, 

 windowless, and provided at one end with a large double door. 

 The floors are covered with sawdust including bits of planks, etc., 

 derived from a saw-mill. The ice-houses are filled during the 

 winter with great blocks of ice taken from the Red River, and are 

 gradually emptied in the spring and summer. After the ice has 

 been removed from an ice-house, the sawdust and pieces of wood 

 on the floor are left undisturbed for some months, during which time 

 lignicolous fungi develop upon them in abundance. As after the 

 removal of the ice from an ice-house the double door is left more 

 or less open, the fungi which develop on the floor are subjected to 

 unilateral daylight. Among the flat Discomycetes found growing 

 in the ice-houses were : Ciliaria scutellata, Melastiza miniata, and 

 Cheilymenia vinacea. 



1 J. Zellner, loc. ciL, p. 139. 2 w. Zopf, Die Pilze, Breslau, 1890, p. 146. 



' E. Bachmann, cited from Zopf, loc. cit. 



