MONOGRAPH OF THE LABOULBENIACEJE. 227 



paradoxus it is nearly horizontal, so that the asci growing inward, downward, and up- 

 ward are much bent and distorted when mature. When they occur in pairs the asco- 

 genic cells are more or less symmetrically arranged, and when there are but two, lie 

 facing one another in a plane at right angles to that in which the perithecium is flat- 

 tened. Where there are two or tour pairs the perithecium is but slightly if at all 

 flattened, and the ascogenic cells lie facing one another : one anterior, one posterior, 

 and two lateral, or approximately so. The form of the ascogenic cell is subject to 

 little variation, being, as a rule, oval in outline in face view ; but in a few genera it 

 is much elongated, as in Amorphomyces (Plate IV, figs. 25-28), or Sphaleromyces, 

 and in the former case may possibly become divided by a transverse septum in certain 

 instances. 



In Stigmatomyces, as has been mentioned, the asci bud from the ascogenic cell, 

 alternating first from one side, then from the other ; so that, as a result, two definite 

 rows are formed, such as are illustrated in Plate IV, fig. 18, in Plate I, fig. 38 (at the 

 left), and in Plate III, fig. 1, all of which represent dorsal views of the ascus mass, the 

 ascogenic cell lying away from the observer and being consequently invisible. In the 

 last mentioned figure, a slight irregularity is noticeable from the fact that an extra 

 ascus has been abnormally produced at one point lying in the median line between the 

 two rows normally formed. The most conspicuous exception to this biseriate arrange- 

 ment of the asci is found in the genus Moschomyces, the very large ascogenic cell of 

 which gives rise to an enormous number of asci arranged in many vertical rows; and, 

 although such variations are exceptional, there seems in a few other cases to be some 

 slight variation from the biseriate type. 



The form of the ascus at maturity is subject to unimportant variations, being 

 practically identical in nearly all the genera. It varies from a somewhat stout and 

 short type (Plate VIII, fig. 28 ; Plate II, fig. 11 ; Plate I, fig. 25) to more slender forms 

 (Plate XI, fig. 17 and Plate XXIV, fig. 9). At the time when the spores are fully 

 formed, the ascus is commonly short-stalked; but as the latter begins to be pushed 

 upward by the ever-increasing mass of asci below it, the basal part often becomes 

 drawn out into a long slender pedicel, which finally sloughs off as the ascus wall itself 

 begins to dissolve. In almost all cases the asci are four-spored at maturity, as in the 

 majority of the figures cited, and are distinctly flattened, the only known exceptions 

 to this rule being presented by the two genera, Moschomyces (Plate XI, fig. 17) and 

 Compsomj'ces, in both of which they are definitely eight-spored and more nearly 

 cylindrical. The asci are never naturally discharged from the perithecium, having 

 wholly dissolved some time before they reach the terminal pore of the latter; but by 



