THAXTER. — 



MONOGRAPH OF THE LABOULBENIACEjE 



22^ 



iiiilcd from, or, on the other hand, have been modified to form conditions such as are found, for example, 

 in Dvmorphomycea, and especially in D. Myrmedonwe, Plate XXVI II, fig. 1 4, in which the elongate second- 

 ary axis, projecting as it does laterally, and at right angles, from the short primary receptacle, may res! 

 against the surface of the host, although it does not become attached to it. Of forms in which both male 

 and female organs occur on the same branches, Monoicomyces furnishes a striking example well illustrated 

 by M. St. Helena 1 , Plate XXXVI, fig. S, in which they are more than usually elongated. 



In this connection attention should be called to certain forms in which the primary receptacle is 

 obliterated at a very early period by the growth of its fertile branch which has the appearance of being 

 directly continuous with it, the two axes becoming coincident. 'Phis condition is found in all species of 

 Rhachomyces, Plates XLIV and XLV, and accounts for the apparently simple axis in most normal indi- 

 viduals of Monoieomyces LeptochiH, Plate XXXIV, fig. 39. Among other forms having two-celled recep- 

 tacles, which seem to belong in this general category, two other genera need special mention, namely 

 Moschomyces and Comp.som.yces, in which the secondary perithecial axes are single appendiculate cells, 

 continuous with and hardly distinguished from the perithecial stalk-cells, so that the perithecium appears 

 to be borne on a double stalk-cell. A somewhat similar condition is seen elsewhere only in the perithecial 

 branches which arise from the massive receptacles of Zodiomyces and Euzodiomyces. 



Turning now to instances in which the basal spore-segment becomes divided more than once to form 

 the primary receptacle, a variety of conditions may be found, but the same general distinctions previ- 

 ously outlined may be recognized. Thus the primary receptacle may be determinate or indeterminate, and 

 the procarps may arise either directly from it, or from its more or less evident lateral branches. 



Instances of determinate receptacles of more than two cells, from which the procarps arise directly, 

 are rare, and may be illustrated by the genus Ceratomyces as limited in the present paper, and by Auioi- 

 comyecs, Plates LXVIII-LXX. Whether the peculiar genus Teratomyces, Plate XLIX-L, might not 

 be included here, is uncertain; since the exact origin of its perithecia is as yet unknown, although they 

 seem certainly not to arise from the third cell of the receptacle. Whether the cell above this should also 

 be regarded as a part of the primary receptacle, has not been determined, in the absence of a complete 

 series from the germinating spore; but both the perithecigerous and the appendiculate cells appear to 

 arise as proliferations from it. The conditions in Symplectromyees, are evidently similar, and the be- 

 ginning of this condition is perhaps illustrated by Idiomyces. 



Of indeterminate receptacles from which procarps arise directly, one of the simplest types is seen 

 in the anomalous genus Choetomyce.t, formerly illustrated; but a complete series, in which the relations 

 between the ultimate products of the two spore-segments can be determined, has not as yet been examined. 

 In contrast to this form in which the number of secondary divisions is small, the cell-number thus varying 

 within restricted limits, Ectcinomyccs may be mentioned as one in which differences due to secondary 

 elongation may be extreme, Plate LI, figs. 15-17, and a similar though less variable condition is illustrated 

 by Hydrophilomyces, Plate LXVIII, figs. 1-2. The female individuals of Dimcromyccs, and even the 

 males, may also be thus secondarily modified, a condition strikingly illustrated by D. pinnatus, Plate 

 XXIX, fig. 16. Enarthromyces, among the monoecious forms with compound antheridia, affords another 

 instance of the same nature; but one in which the secondary elongation does not result, as in the last 

 mentioned instance, from continued division of the basal cell. 



Among types in which the procarps are borne on branches which arise from indeterminate primary 



