CHAPTER III.—SPORES OF FUNGI. 69 
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 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 —_Fic.as. @ Cystopus Portulacae; m mycelial branch bearing 
isolation of the spore is effected. It is i explained in tne um 6 Euronen paren 
natural to suppose that this process de- on which ee of oo ee ai 
scribed as disappearance consists in a  syoungestsporeofactiin a mark meet 
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 (2) is effected by a broad cross septum to form a gonidium (v). 
