174 DIVISION II,—COURSE OF DEVELOPMENT OF FUNGI. 
of the ovuleremains undifferentiated, and an abundant formation of new hyphae is 
constantly taking place in it. This new formation is so added from below to the 
differentiated portion, that the latter constantly increases in height without becoming 
materially broader, and maintains therefore the form of a cylinder pointed at the upper 
end. Where the parts below approach the wall, columella, and spore-mass, they assume 
their structure and colour. In other words, each of the three portions grows from its 
base by addition of new tissue-elements, which are constantly being produced and 
pushed onwards from a basal formative tissue, and are differentiated and assume their 
ultimate form in the order in which they are produced (Fig. 8° C and D). The 
development and mature structure of the spore-mass are the same as those of Ustilago, 
which will be described presently. The 
wall in its fully developed state is a thick 
coat formed of many irregular layers of 
small round cells not very firmly united 
together. These cells are formed in the 
same way as the spores from the hyphae 
of the primary tissue, and are of about the 
same size as the spores with a delicate 
colourless membrane, and for the most 
part with watery hyaline contents. The 
columella has the structure of the wall, 
but it usually incloses in its tissue evident 
brownish fragments of the tissue of the 
ovule, and consists at its uppermost ex- 
tremity of much larger, firmer hyaline 
cells, the origin of which I am unable 
to explain. I may also observe that the 
upper extremityin youngspecimens always 
ends blindly in the spore-mass (C), but 
in some older ones reaches to the apical 
portion of the wall and passes into it (D); 
it is still uncertain whether this is a dif- 
ference in the individual plants or a 
difference of age. 
The spore-receptacle which has now 
been described is formed only from the 
ovule. The perianth and stamens of the 

FIG. 80. Spacelotheca Hydroptperis in the flower of Polygonum 
Hydropiper. A ripe compound sporophore of the Fungus pro- 
jecting from the perianth of Polygonum. B the same with the 
mass of spores emerging from the sporophore. C median longi- 
tudinal section through a young fructification and its environ- 
mhent, D longitudinal section through an older sporophore, c the 
columella, # the perianth, /the wall of the ovary, o the integument 
(mycropyle) of the ovule, g the style. In C and D the sterile 
or young tissue of the Fungus is shaded by longitudinal lines, the 
mass of ripening spores is darker. Further explanation in the 
text. Slightly magnified. 
flower continue in their normal state. 
The wall of the ovary and the style are 
also not attacked by the Fungus; they 
do not follow the growth of the spore- 
receptacle, and as this advances the 
lateral wall is distended and at length 
bursts transversely ; the style with the 
upper portion of the wall dries up into a 
small point at the apex of the receptacle, which is borne by the latter as it grows out of 
the perianth (4). The wall of the spore-receptacle, especially where it is covered above 
by the withered remains of the wall of the ovary, is very fragile and tears asunder at 
the slightest touch to discharge the spores (2). 
Section LV. Thedevelopment of the resting-spores commences in Entyloma 
(Fig. 81 a), as in Protomyces, with intercalary abjunction at any spot in the hyphae ; 
in Tilletia the resting-spores are terminal, being formed singly from the extremities of 
branches of sporogenous hyphae. In Geminella Delastrina they originate by serial 
