313 
THALLOPHVTES. 
become multicellular in consequence of the formation of transverse septa within them, 
and, lying closely side by side, they give rise to a pseudo-parenchyma. From the 
internal surface of this investment, as it increases in size, short filaments are given 
off which fill up the space between it and the carpogonium which has not as yet 
undergone much change (V h). The still unicellular carpogonium now begins to 
grow vigorously; it is divided by a transverse septum into two cells, an upper and 
a lower, and may be regarded as a simple form of ascogenous filament, the apical 
cell of which is directly converted into an ascus (V a). The apical cell, by its rapid 
growth, soon occupies the whole of the cavity of the fructification, and eight spores 
are produced by free-cell-formation in its protoplasm. Slight pressure upon the fruit 
causes the extrusion of the ascus (II a). In other Erysipheae, the perithecia of 
which contain several asci, as E, Umbelltferarum, communis, lamprocarpa, etc., the car- 
pogonium is also originally unicellular, but it grows within the investment into a long, 
thick, curved filament, which is divided into segments by numerous septa. Many of 
these segments throw out lateral branches which bear the asci. 
Fig. 207. — / Conidiophore ; // ripe perithecium of Erysiphe (Sphcerotheca) pannosa (after Tulasne) ; /// carpo- 
gonium and pollinodium ; IV the same after fertilisation ; V the young perithecium of Podosphcera Castagnei (after ' 
De Bary) ; c carpogonium ; p pollinodium ; h wall of the perithecium ; a the single ascus. 
These Erysipheae which have numerous asci afford a transition to the Eurotieas^ in 
which the carpogonium, even before fertilisation, elongates considerably and becomes 
spirally wound. 
The life-history of Eurotium repens and that of Eurotium Aspergillus glaucus have 
been also recounted in detail by De Bary. Both species are found on the most 
various decaying or dead organic bodies, and are especially abundant on preserved fruit. 
The Fungus makes its appearance as a delicate flocculent white mycelium overspreading 
the surface, from which the upright conidiophores soon rise in large numbers. These 
swell in the upper part into a globular form, and on the upper half of the globe 
there arise a number of peg-shaped projections, densely crowded and arranged radially, 
the sterigmata, each of which produces gradually a long chain of greenish conidia; 
so that finally the head of the receptacle is covered by a thick layer of them. During 
this formation of conidia, the sexual organs appear on the same mycelium. The female 
organ, the carpogonium, is the corkscrew-like end of a branch of the mycelium (Fig. 208, 
A, as), the coils of which become gradually closer, until, when actually in contact, they 
form a hollow spiral (jB, C). During this process about as many septa are formed as 
there are turns of the helix {i.e. 5 or 6). From the lowest coil of the carpogonium two 
^ [Wilhelm, Die Pilzgattung Aspergillus, 1877.] 
