148 



RESEARCHES ON FUNGI 



loses all its protoplasm except a very thin layer lining the cell-wall 

 which is necessary for preserving the cell's turgidity. Within a 

 few minutes after the spores have been shot away, the basidium- 

 body dies. Although the slow passage of the cytoplasm and the 

 four nuclei from a basidium-body of a single individual living 

 basidium into the four spores has not been actually observed in 

 detail, from comparative observations on living and on fixed and 



stained basidia in all stages of 

 development we are justified in 

 believing that it actually occurs. 

 By inference, therefore, we are 

 entitled to regard it as a definite 

 instance of protoplasmic stream- 

 ing in hymenomycetous fruit- 

 bodies. 



The biological significance of 

 protoplasmic streaming in the 

 Hymenomycetes is the same as 

 in the Pyrenomycetes and Dis- 

 comycetes, i.e. it serves to supply 

 protoplasm to rapidly growing 

 hyphae wherever these may be 

 situated. 



With the discovery that, in 

 the Hymenomycetes, protoplasm 

 can flow rapidly from cell to cell 

 through the pores of the septa, 

 light is thrown on the means whereby hymenomycetous fruit-bodies 

 in general obtain the nutriment required for their upbuilding. 

 Everyone with an interest in living things is apt to be astonished at 

 the rapidity with which such large fruit-bodies as those of Polyporus 

 squamosus, Boletus edulis, Lepiota procera, etc., grow to maturity ; 

 and, when confronted by the phenomenon, a plant physiologist 

 naturally asks : how is the required nutriment transferred so 

 quickly from the mycelial hyphae to the sporophores ? Formerly 

 there was no satisfactory answer to this question. Now we can 

 answer it as follows. When a Polyporus squamosus or other large 



75. — Coprinus sterquilinus. A, a 

 young basidium full of protoplasm; 

 above, a fusion nucleus. B, a 

 slightly older basidium with va- 

 cuoles v below and four haploid 

 nuclei above. C, a much older 

 basidium ; the small vacuoles have 

 united to form one large vacuole v 

 which is expanding and driving 

 the labile protoplasm into the 

 spores. Magnification, 612. 



