442 



THAXTER. MONOGRAPH OF THE LABOTJLBENIACE^E. 



plane, and other branches coming from cell (h) both above and below, are not shown. The parietal 

 branches appear to be developed near the bases of the wall-cell branches, but are small and hardly dis- 

 tinguishable, their functions being usurped as will appear later, by the wall-cells themselves. 



Even while this development of branches is taking place the two basal cells (o) and (h) begin to be 

 pressed down by the structures to which they have given origin above, into the cell below from which 

 they originated, and as the development of the ascogonium proceeds this cell, like the cells above it, loses 

 its identity as a cell; the whole series being transformed to a continuous cavity within which the whole 

 ascogenic apparatus eventually lies quite free. The procarp resembles other procarps of this group, 

 consisting of an ascogonium, an inferior and a superior supporting cell, followed by a trichophoric cell; 

 above which the unicellular, sparingly branched or lobulated trichogyne emerges, as has been already 

 described (figs. 11-12). As the perithecium matures and the ascogenic cells become active, only two or 

 three wall-cells which have become indurated and cohere closely to the inner surfaces of the cells within 

 which they were formed, persist, as shown in the bent termination of fig. 7, to form the tip of the functional 

 perithecium. The cavity of the perithecium is thus the cavity of the cell from which the perithecial branch 

 system originated combined with the cavities of the cells through which these branches penetrated; and 

 its walls, except at the tip, as above mentioned, are the walls of these cells. The structure may thus be 

 termed a pseudoperithecium. 



If then one examines the conditions found when the plant is fully mature it will be seen to consist 

 of the same three regions distinguished in the young condition. The terminal region, however, above 

 the appendiculate cells, excepting only its basal cell which acts as a false stalk-cell to the pseudoperithe- 

 cium, has become transformed into a single chamber, the wall of which corresponds to the combined 

 walls of the four or more cells which were superposed above the basal cell of the series comprising 

 this distal region. Within this chamber have developed from the subbasal cell of the series, structures 

 which correspond to all those found in the normal perithecium of the Laboulbeniales. Of these struc- 

 tures, however, all are eventually disorganized with the exception of a few small wall-cells, which persist 

 distally and are functional in regulating the spore-discharge, and the ascogenic cells, of which there appear 

 to be four. These ascogenic cells, then, together with the usual mass of asci and spores, float free within 

 a structure resembling a perithecium and performing the same function, but which when viewed super- 

 ficially has absolutely nothing in common with any of the structures seen in perithecia of the normal type. 



Such an endogenous origin of the perithecium has no parallel in the other genera, unless it be in 

 Zodiomyces and perhaps also in Euzodiomyces. In the former the perithecigerous area arises endoge- 

 nously in a somewhat similar fashion, and if in the present instance the perithecial structures persisted, 

 and the walls of the cells into which they penetrate were eventually destroyed, the conditions would be 

 closely comparable: the differences depending merely on the differences in the general cell structure of 

 the body of the plant in either case; the complicated multicellular body of Zodiomyces producing many 

 perithecia where the present simple type gives rise to but one. The character and origin of the antheridial 

 branches in the two cases are however totally different. 



The antheridial appendages in the present genus are peculiar, from their position on the primary axis 

 below the perithecium, a condition seen nowhere else unless possibly in Chcetomyces; although such an 

 arrangement, as in Clematomyces, is often seen in branches from this axis. The antheridial cells them- 

 selves are merely the lower cells of the appendage or its branches (fig. 13), from which short outgrowths 

 arise that are converted into discharge-tubes through which the sperm-cells make their exit as in simple 

 antheridia of the ordinary type. The conditions present in the antheridial appendages in this instance do 

 not therefore appear to differ essentially from those seen, for example, in Rhadinomyces; except that the 

 series of antheridial cells is not definitely differentiated. At the same time the conditions described are 

 very similar to those in Rhynchophoromyces and illustrated in my Monograph, Plate XXIV, fig. 24: but 

 whether the sperm-cells in the present instance possess a wall, as in Rhynchophoromyces, I am not able to 

 say. The antheridial characters of Coreomyces thus tend to break down the distinction formerly assumed 



