194 DIVISION II. COURSE OF DEVELOPMENT OF FUNGI. 



the surface of four-sided prismatic cells ; the cells in each layer are arranged in rows 

 which radiate from each cone and meet those which proceed in the same manner from 

 the neighbouring cones. A section parallel to the surface is consequently made up 

 of delicate roundish facets composed of radiating rows of cells, each of which has in its 

 centre a group of thick-walled bright yellow cells. 



A loosely felted weft of slender hyphae with elongated segments proceeds on all 

 sides from the inner surface of the peridium and traverses the gleba ; here and there, 

 especially in younger specimens, the hyphae are more closely combined into larger 

 plates or strands, but there are no distinctly closed chambers. The gaps in the weft 

 of slender filaments are everywhere loosely filled with ascogenous hyphae twice or 

 thrice the thickness of the other hyphae, which are divided into short cells and 

 are often coiled into knots and bear asci on the extremities of their branches. As 

 the spores ripen the whole of the ascogenous tissue becomes mucilaginous and 

 disappears, while the tissue with the slender filaments remains behind as the delicate 

 ' c apillitium ' between dry masses of spore-dust. On the asci and on the ripening of 

 the spores, see above, pp. 80 and 97. The spores are' large and globular and remarkable 

 for the enormous thickness of their walls, which may be more than two-thirds of the 

 semidiameter of the spore ; the wall consists chiefly of a thick, gelatinous, stratified, 

 colourless membrane, covered on the outside with a thin but firm and darkly coloured 

 episporium. For further details see Tulasne's Fungi hypogaei and De Bary's Frucht- 

 entwicklung der Ascomyceten. The germination of the spores has not been observed. 



A few observations only have been made on the early stages of the development 

 of Elaphomyces. 



The youngest sporocarps of E. granulatus which have come under my notice 

 are small round bodies from i to 2 mm. in size in the interior of a compact dirty- 

 yellow filamentous mycelium. Their outside is covered by a cortical layer of the 

 same thickness, colour, and warty surface as in full-grown specimens, and consists of 

 a thin-walled pseudo-parenchyma, the elements of which are often in continuous 

 connection with the mycelial hyphae. The cortical layer encloses a tissue-mass of 

 delicate closely woven hyphae, which fills the whole of the interior and shows the 

 same structure, but is differently coloured in different parts ; a small central portion 

 is of a whitish colour, and is surrounded by a dirty-violet layer, between which and 

 the cortex is a narrow white zone. Later states show that the whitish central mass 

 becomes the gleba, the rest the peridium. This structure and the relative size of 

 the separate portions continue unchanged till the sporocarp has reached the size 

 of a large pea. Larger specimens show the gleba proportionately more enlarged than 

 the peridium, and the ascogenous hyphae beginning to be developed between the 

 slender filaments of its original tissue ; soon after the gleba forms the chief mass of 

 the sporocarp, which grows by degrees to the size of a hazel-nut. While the 

 peridium consequently increases greatly in circumference, its absolute thickness 

 increases at the same time or does not diminish. The structure of the inner layer 

 and especially the thickness of its hyphae remain all this time unchanged ; the cells 

 also of the cortical layer become only about one half larger than in the first observed 

 stage, while the warts multiply so that without altering much in size they always 

 closely cover the surface of the sporocarp, their multiplication being effected by 

 the splitting of one wart into two or more. All this shows that growth must take 

 place up to late stages in the development by simultaneous and continued formation 

 of new cells in all parts. Tulasne's figures agree with the above account, except in 

 the statement that young specimens must at first be hollow ; the difference arises 

 perhaps from variations in the species examined. All the facts seem to show that we 

 have in Elaphomyces a sporocarp with an extremely thick envelope-apparatus and 

 formed of all the described parts except the ascogenous hyphae. The whole recalls 

 the sporocarp of Penicillium, as will be seen from the description of that genus below. 

 2. The sporocarps of the Tuberaceae have the forms of tubers, which either have 



