554 
Fraser . — The Development of the 
Mycelium. 
The mycelial hyphae vary very much in thickness. They branch 
freely, often in a dichotomous manner. In some cases they are richly 
septate, in others, especially in the rooting hyphae, the septa are far apart. 
Conspicuous granules, the so-called metachromatic granules commonly 
observed in Discomycetes, are present on the cross-walls. H-pieces and 
other anastomoses between neighbouring hyphae are of frequent occurrence 
(PL XLII, Figs. 3, 4). The cells contain a network of finely granular cyto- 
plasm, and are multinucleate. 
Formation of Archicarp and Sheath. 
Usually, but not invariably, the archicarp is produced on one of the 
larger filaments. It forms two or three close coils and undergoes septation 
(Figs. 2, 7). 
At this time the hypha which bears the archicarp and others in the 
immediate neighbourhood give rise to numerous stout, curved branches. 
These are the beginnings of the sheath. They grow up and invest the 
archicarp and the hypha which bears it, till a more or less spherical mass is 
produced (Figs. 4, 5, 6). Branches from increasingly remote hyphae are 
added as development proceeds, and rooting filaments grow downwards to 
form a secondary mycelium (Fig. 4). 
At this stage the fruit is remarkably like the young perithecium of 
the simpler Pyrenomycetes or of such a mould as Aspergillus , and it is 
only later, when the development of the paraphyses takes place, that the 
distinctively discomycetous character is established. 
In the meantime the archicarp has undergone further development. It 
grows out beyond the coiled portion as a long, sinuous, multicellular 
filament (Fig. 8), which grows among the cells of the sheath and ultimately 
protrudes far beyond them (PI. XLII, Fig. 11, PI. XLIII, Fig. 12). 
At first, all the cells of the archicarp contain scattered nuclei similar to 
those of the vegetative hyphae (Fig. 7) ; a little later the nuclei in the 
central and terminal cells have become more numerous (P 4 g. 8), and still 
later three regions are clearly differentiated. The cells of the stalk differ 
little from those of the vegetative mycelium. The coiled central region is 
made up of three or four cells ; these enlarge and their nuclei increase both 
in size and number. The terminal portion constitutes the trichogyne. 
Trichogyne. 
This terminal part consists of some eight or nine cells ; it becomes 
more or less emptied of contents, and a peculiar change takes place in the 
character of the transverse septa. They show a large, clear, central area 
(Figs. 5, 11, 12), resembling in appearance the callus-pad of a sieve-tube, 
and staining readily with erythrosin. 
