56 TEXT-BOOK OF FUNGI 



charomycetes the formation of endospores or, properly, asco- 

 spores, is the result of a sexual act. 3. In some species 

 ordinary cells become thick-walled and form resting-spores. 



In the Basidiomycetes the spores are formed by what 

 De Bary terms acrogenous abj unction. The mother-cell, 

 or basidium, is surmounted by a definite number of slender 

 outgrowths most frequently four called sterigmata. The 

 apex of each sterigma becomes swollen and forms a spore 

 which at length is cut off from its sterigma by a cross-wall 

 or septum. Spores formed on basidia are often called 

 basidiospores. In the Hymenomycetes the spores separate 

 from the apex of the sterigma, leaving the latter attached 

 to the basidium. In the genera Lycoperdon and Bovista, 

 belonging to the Gasteromycetes, the sterigma remains 

 attached to the spore when it is shed, hence the spore with 

 its attached sterigma resembles a miniature drum-stick. In 

 the genus Calocera and Dacryomyces each basidium bears 

 only two sterigmata, whereas in Octaviania, Hymenogaster, 

 and others of the subterranean forms, the number of sterig- 

 mata is variable. Finally, in some of the Gasteromycetes 

 sterigmata are absent, and the spores spring direct in a 

 sessile manner from the apex of the basidium. This occurs 

 in species of Geaster, Polysaccum^ Phallus , Scleroderma, 

 etc. No basidium produces more than one crop of spores, 

 and these are developed simultaneously. 



It has been known for some time that the formation of 

 spores contained in sporangia in the members of the 

 Mucorineae presented some peculiarities. Leger investi- 

 gated this subject, and showed that in all cases a differen- 

 tiation of the protoplasm contained in the sporangium into 

 a dense peripheral portion and a less dense central portion 

 occurred; that numerous nuclei were present, and that 



