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RESEARCHES ON FUNGI 



hymenium more from the side of the fruit-body than from the free 

 end. Probably, therefore, in Otidea onotica and 0. leporina the asci 

 are bent heliotropically toward the open side of the fruit-body rather 

 than to the free end. The Otideae puff freely when their mature 

 fruit-bodies are touched, and then the clouds of spores which they 

 emit through their asymmetrical openings can be readily observed. 



Fig. 151. — Otidea onotica, a Disconiycete witli auriculate fruit-bodies. Tlie long 

 lateral opening down the side of each fruit-body enabled the light to strike the 

 hymenium more or less perpendicularly and thus, doubtless, to stimulate the 

 asci heliotropically, so that the ends of the asci turned themselves toward the open- 

 ing. \\'hen spore-discharge took place, therefore, the ascospores could readily 

 be shot away from the fruit-body into the open air. Fruit-bodies shown were 

 collected at the Experimental Farm, Ottawa, by W. S. Odell. Photographed 

 by the Photographic Division of the Geological Survey of Canada. Natural size. 



The Heliotropism of the Asci and the Discharge of the Spores 

 in the Morchellaceae. — In the Morchellaceae, which includes the 

 genera Morchella and Mitrophora : the fruit-body or receptacle is 

 differentiated into a stipe and a pileus ; the pileus is hollowed out 

 externally into pits or alveoli ; the hymenium is broken up into 

 separate portions, each of which lines the interior surface of one of 

 the alveoli ; and the alveoli are separated from one another by ribs 



