CHAPTER III. — SPORES OF FUNGI. 



6 9 



also the rest of the hymenial tissue, becomes entirely dissolved by processes of decom- 

 position not accurately known, and the spores are thus set at liberty. They lie at first 

 in the place where they were formed ; their subsequent fortunes are described in 

 Division II. The history of the basidia, which make their appearance as branches 

 of the simple sporophores and form gonidia in Peziza Fuckeliana ('Botrytis cinerea'), 

 is essentially the same. They disappear entirely after the gonidia are ripe, and the 

 latter cling in loose heaps to the place of their formation. 



The process of abscision is the most common of the three and appears with the 

 greatest variety of forms. Generally a transverse zone between the adjacent cells 

 disappears or grows soft, and their separation is thus effected or made easy. The 

 transverse zone which disappears is either 



a 



a middle lamella of the cross septum 

 between the two cells or it is a small 

 stalk-cell, which is cut off from the young 

 spore by a cross septum and then dis- 

 appears, as in the uredo-chains of Coleo- 

 sporium and Chrysomyxa and all the 

 Aecidieae. The changes observed in the 

 zone of separation are in one series of 

 cases simply that it becomes gradually 

 smaller and especially narrower and at 

 length entirely disappears ; in other cases 

 it swells up into a jelly and becomes 

 disorganised. The product of the swelling 

 may in the latter case be persistent, and 

 is then usually increased to a considerable 

 extent by the gelatinisation of the lateral 

 walls of the spores, which are therefore 

 ultimately glued together by a gelatinous 

 mucilaginous gummy substance ; in other 

 cases the products of disorganisation at 

 length entirely disappear, and complete 

 isolation of the spore is effected. It is 

 natural to suppose that this process de- 

 scribed as disappearance consists in a 

 transformation into soluble compounds 



and a simultaneous osmotic absorption of these into the adjacent cells, especially 

 in the many cases in which the spore about to be removed by abscision continues 

 to grow while the disappearance is proceeding, and would seem therefore to be 

 receiving more food. In some cases one might also suppose a process of com- 

 bustion. Precise statements on these points are not possible in the present state 

 of our knowledge. 



These phenomena are well exemplified in the simple successive gonidial rows in the 

 genus Cystopus, especially in C. cubicus and C. Portulacae (Fig. 35 a), which latter 

 plant is more particularly referred to in this place. Delimitation of the rounded apical 

 portion of the basidium (p) is effected by a broad cross septum to form a gonidium (//). 



FIG. 35. a Cystopits Portulacae ; «; mycelial branch bearing 

 two basidia which are producing gonidia by abjunction ; the figure 

 is explained in the text. * Eurotium Aspergillus glaucus ; 

 r extremity of a sporophore covered with radiating sterigmata, 

 on which the formation of spores is just beginning, j and t 

 isolated portions showing single sterigmata// with their spores ; 

 n youngest spore of a chain, a magn. 390, the rest 300 times. 



