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- 

 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. 



11. Scleroderma vul- 

 gar -e, one of the Gastro- 

 mycetes. A piece of a 

 mass of tangled basidia 

 which fills each glebal 

 chamber. The basidia 

 lack sterigmata and the 

 sessile spores are not 

 violently discharged. After 

 Tulasne, from von Tavel's 

 Vergleichende Morphologic 

 der Pilze. Highly magni- 

 fied. 



