SPORE-DISCHARGE IN THE CLAVARIEAE 185 



those parts of the ultimate branches which look more or less 

 downwards and never on those parts which look more or 

 less upwards 1 ; and the same kind of stimulus may be more 

 or less effective in Clavaria. Here again there is room for an 

 experimental investigation. 



The upper angles between the branches in many species of 

 Clavaria are very obtuse or rounded out. This causes a marked 

 separation of the branches at their bases and enables the main shafts 

 of the branches to grow upright with a minimum of mutual 

 interference. In such species, also, the inter-ramal spaces are well 

 developed. This increases the ease with which the wind may sweep 

 through the fruit-body and carry away the spores. In some species, 

 e.g. Clavaria pyxidata, the branches, when they happen to grow 

 toward one another and press against one another, fuse at the points 

 of contact. This enables the fusing branches to act as a unit 

 in rebranching, instead of independently, and at the same time 

 strengthens the fruit-body mechanically. 



The basidia of the Clavariae are unicellular and have four 

 sterigmata and four spores, and they therefore resemble the basidia 

 of the Agaricineae and other non-tremelloid Hymenomycetes. The 

 spores are discharged in the usual manner, i.e. violently and after 

 a drop of watery fluid has been excreted at the hilum. I observed 

 spore-discharge with the microscope more particularly in Clavaria 

 formosa. A subterminal branch bearing several terminal branches 

 was placed in a closed compressor cell ; but, under these conditions, 

 the basidia ceased to discharge their spores properly and the cover- 

 glass became fogged. I therefore laid a similar piece of the fungus 

 on an ordinary glass slide and covered it with the cap of a large 

 compressor cell. As this cap was greater in diameter than the 

 width of the slide, ventilation spaces were left open below on each 

 side of the slide. Under these conditions there was no fogging of 

 the cover-glass of the cell cap and the basidia behaved normally. 

 Shortly before a spore was to be discharged, a drop began to be 

 excreted at the spore-hilum. As soon as this drop had grown for 

 about five seconds and had attained a diameter equal to about 

 three-quarters or the whole of the diameter of the spore, the spore 



1 Vide infra. 



