226 



THAXTER. 



MONOGRAPH OF THE LABOULBENIACE^E. 



receptacles, the most striking and peculiar is seen in Kainomyces, the massive receptacle of which gives 

 rise to lateral axes of superposed cells terminated by perithecia, Plate LXXI, figs. 20-21. Zodiomyces 

 and En zodiomyces, both conspicuous for their massive receptacles, also produce their perithecia termi- 

 nally on short branches, as has been already mentioned. A very peculiar type which seems to belong here, 

 although no young material has been examined, is seen in Clematomyces, Plate XL1II, fig. 1. Here a 

 stout main axis, consisting of a double row of cells, gives rise to a variable number of branches similar to 

 it in structure; but how much of the former corresponds to the basal spore segment it is not possible to say. 



Lastly the genus Dii'homyccs which, by assuming a scale-like habit, has beautifully adjusted itself to 

 its life on the abdomen of a swiftly running host, illustrates a condition in which a seemingly broadly 

 muticellular primary receptacle consists in reality of a central and invariable axis of superposed cells, 

 corresponding to the basal spore segment, which produces branches right and left above the basal cell, 

 in many species symmetrically paired. Although these branches may be variably united to one another 

 above and below, and thus give the appearance of a cellular mass, they may in other cases be almost 

 wholly free, especially the upper pair, as is well illustrated by D. biformis, Plate XXXIII, fig. 3. The 

 genera Pcyritschiclla, Limnaiomyccs, Chitonomyces and Hydraeomyces are all more or less evidently 

 similar in the development of their receptacles. In the very closely allied genera Rickia and Distich- 

 omyces, which, however, form a well marked group by themselves, the development of the receptacles, 

 which is given in some detail below under these genera, although of a different character from that of the 

 D ichomyrcs-type, is similarly resolvable into series of coherent branches. 



Before leaving the subject of receptacles, attention should be called to certain peculiar modifications 

 of the basal cell which are evidently protective, acting as supports or buffers, and consist of more or less 

 indurated outgrowths, most conspicuously illustrated by Kleidiomyces, Plate XXXVII, fig. 3, and to a 

 less extent by Corethromyccs Stilici, Plate L, figs. 6-9. A similar supporting and protective function is 

 no doubt served by the blackened fork-like upgrowths from either side of the subterminal tier in many 

 species of Dichomyces, Plate XXXII, although these structures, being modified tips of lateral branches, 

 are morphologically quite different. In this connection the remarkable extension of the basal cell in 

 species of D imorphomyces, and especially in D. Myrmedoniw, Plate XXVIII, fig. 14, should be referred 

 to, forming as they do a continuous supporting margin below the laterally developed sympodial peri- 

 thecigerous branch. The small beginnings of conditions such as the two first above mentioned, are to 

 be found in such occasional modifications as were formerly described and figured in connection with 

 Laboulbenia Philonthi and Compsomyces verticillatus, Monograph, Plates XI, fig. 13 and XXII, fig. 28, 

 and the foot-like modification of the receptacle in various species of Ceratoinyces undoubtedly serve a 

 similar purpose. 



Appendages. An appendage of some kind is present in all genera with the single exception of Amorph- 

 omyces, which in this, as in other respects, is the simplest known generic type. In all others, the spore 

 being two-celled, the distal segment is transformed into a structure corresponding to a primary appendage, 

 although in male individuals of unisexual types having simple antheridia, like Dioicomyccs , the distal 

 segment may be transformed directly and in toto to an antheridium. The new genera here included 

 offer few general types not described in the former Monograph; but certain ones need special mention, 

 which may be more conveniently made in connection with a brief review of the more important types of 

 antheridia. The distinction between the primary appendages, which are always derived from the upper 



