l5 o RESEARCHES ON FUNGI 



the enlarging vacuoles of the elongating stipe-cells can be readily 

 drawn up by suction pressure from the mycelium in just such 

 amounts as are required. 



The ripe spores of a hymenomycetous fruit-body are always full 

 of dense protoplasm and, as a fruit-body discharges more and more 

 of its millions of spores, it becomes more and more exhausted of 

 protoplasm. At last, when spore-discharge is ceasing or has ceased, 

 most of the space in every cell of the stipe, the pileus-flesh, the 

 trama, the subhymenium, and the hymenium (paraphyses) is occu- 

 pied by one or a few very large vacuoles. Doubtless, as these 

 vacuoles enlarge and drive out protoplasm toward the basidia, much 

 of the water required to increase the volume of the cell-sap is drawn 

 into the vacuoles through the protoplasm of adjacent cells from a 

 distance. The ultimate source of the water which enters these 

 enlarging vacuoles may sometimes be water in other cells of the 

 fruit-body, sometimes water stored between the pileus-flesh cells, 

 and, sometimes, possibly, water contained within the mycelium in 

 contact with the substratum. 



Mycetozoa and Fungi. — The flow of protoplasm in a plasmodium 

 of a Mycetozoan toward some place where the sporangium or 

 sporangia are to be formed is comparable to the flow of protoplasm 

 in the mycelium of Phycomycetes, Discomycetes, Pyrenomycetes, 

 and Hymenomycetes toward the sporophores. In both Mycetozoa 

 and Fungi, the protoplasm formed in the vegetative part of the 

 organism often flows a distance of several inches or feet to the place 

 where the spores are to be developed. 



Phycomycetes compared with Ascomycetes and Basidiomycetes. 

 — We now know that protoplasmic streaming takes place in the 

 mycelium of species belonging to all the three great groups of fungi : 

 Phycomycetes, Ascomycetes, and Basidiomycetes. 



In the Mucorineae streaming is characterised : (1) by frequent 

 reversals in the direction of flow of the protoplasm ; (2), at least 

 sometimes, by a peripheral current of protoplasm flowing in a 

 direction opposite to that of the main stream ; and (3) by a general 

 movement of the vacuoles. 



On the other hand, in the Higher Fungi streaming is character- 

 ised : ( 1 ) by the flow of the protoplasm for an indefinitely long time 



