A MONOGRAPH OF THE GENUS PODAXIS DESV. (= PODAXON FR.). 71 



stage ? It is certain that the entire group of the Gastromycetes 

 have sprung from the Titberacea, and it is equally evident that the 

 efforts to change an entirely subterranean condition for an above- 

 ground one at maturity is closely connected, if not entirely con- 

 cerned, with securing a more perfect method of spore-dissemination; 

 remembering that the structure of the primitive stock — the Tubera- 

 cete — consists of a hymenial portion producing spores in asci entirely 

 surrounded by a stout wall, spore-dispersion depending on general 

 decay, or in some instances the entire fungus is eaten by animals, 

 and the spores consequently removed ; nevertheless it is obvious 

 that such a structure must undergo a considerable amount of 

 modification on emerging above ground before the desired freedom 

 and facility in spore-diffusion is attained. 



We have evidence of four distinct attempts to effect this object 

 by the subterranean prototypes of the modern above-ground Gastro- 

 mycetes, and if we estimate the success of each attempt by the 

 numbers and distribution in space of its respective members, we 

 find that three out of the four have proved failures, the successful 

 idea being that which evolves from the conversion of asci into 

 basidia, coinbined with a copious, more or less elastic capillitium, 

 this being the structure of all the above-ground Gastromycetes, and 

 the one from which, as already explained, the yet more perfect 

 spore-diffusion through insect-agency evolved. 



Of the three unsuccessful attempts to adapt the subterranean 

 structure to aerial requirements may be mentioned: — (1) The total 

 suppression of the outer thick protecting wall or peridium, leaving 

 nothing but the hymenial portion, part of which was necessarily 

 exposed, as in Gautiera; this scheme, so far as is known, only 

 extended to one genus, containing two species. (2) The outer 

 peridium pierced by a terminal aperture, thus following the idea 

 characteristic of the SpJuzriacea, kept up by one genus, Pachyphlceus, 

 containing but few species. (3) The conversion of that portion of 

 the ascogenous hypha that immediately produces the asci into a 

 basidium, and the development of an abundant, more or less elastic 

 capillitium, as illustrated by the group evolving from Podaxis as a 

 connecting-link with the primitive ascigerous stock, and including 

 the genus Tulnstoma, and in all probability Batarrea and Queletia. 

 The two first-named genera each contain a considerable number of 

 species, and, as already stated, although comparatively rare, have a 

 wide geographical range, suggestive of antiquity ; and possibly the 

 present known species may be looked upon as the survivors of a 

 once more numerous group, illustrative of the earliest attempt on 

 the part of the altogether subterranean Tuberacea to improve their 

 condition and extend their range, by placing themselves under 

 more favourable surroundings at the period of spore-dissemination. 



It is interesting to note that, however far removed the members 

 of the Gastromycetes have become from the parent subterranean 

 stock in the matter of spore-diffusion, yet in almost every instance 

 the whole of the differentiation of the gleba up to the period of 

 spore-formation takes place before the fungus is elevated above 

 ground, and without a clear explanation of the sequence of develop- 



