BASIDIA AND THE DISCHARGE OF SPORES 31 



for instance, in the two species already mentioned and in the various 



species of Lycoperdon. However, the most striking feature of 



the gastromycetous basidium is the variability of the sterigma. 



In some species, e.g. Phallus impudicus and Scleroderma vulgare 



(Figs. 10 and 11), the sterigmata are so exceedingly short that 



they only just suffice to attach the spores to the basidium-bodies 



from which they have been developed. In Lycoperdon, the 



sterigmata are usually long but extra- 



ordinarily thin. In L. gemmatum they 



are narrowly cylindrical in form and 



very variable in length and arrangement 



(Fig. 12). In L. nigrescens each basidium 



usually has four very slender sterigmata 



of about equal length, but the sterigmata 



break across and remain attached to the 



spores when these are set free. Further- 



more, in Gastromycetes, e.g. Phallus, 



Scleroderma, and Lycoperdon, each spore 



,. . , . ,, 



is usually situated symmetrically upon 

 the top of its sterigma instead of being 

 laterally inclined. It will not be neces- 



n 



sary here to give any further details 

 of the structure of gastromycetous 

 basidia. Enough has been said by 

 way of illustration, and we may now 

 ask the question : why are gastromycetous basidia so different 

 from hymenomycetous ? My own answer is as follows. The 

 typical sterigma in association with the spore-hilum, such as we 

 find generally in Hymenomycetes, is to be regarded as an organ 

 for the violent discharge of the spore which the sterigma develops. 

 This violent discharge of the spores, brought about by secret 

 means by the sterigmatic guns, as I showed in Volume I, is of the 

 very greatest importance to Hymenomycetes, in that it permits 

 of the spores escaping from the hymenium into the air and thus 

 becoming disseminated by the wind. 1 In Gastromycetes, on the 

 other hand, the mode of spore-liberation is entirely different from 

 1 Researches on Fungi, vol. i, 1909, pp. 133-134. 



n __ Scleroderma vul . 

 gare, one of the Gastro- 



mycetes. A piece of a 



mass O f tangled basidia 



lack sterigmata and the 



sessile spores are not 



violently discharged. After 



der Pike. 



Highly magni- 



