MONOGRAPH OK THE LAB01 ■ IJiKNIACE^E. 



2 1 3 



in Tlelniinthophiina there are tour rows symmetrically arranged (Plate VIII, fig. 10) on 

 the single appendage. In all these eases the antheridial cells are themselves branch- 

 lets from the axis of the appendage. In Rhadinomyces and Corethromyces, how- 

 ever, the entire axis of the antheridial branch is formed from the superposed venters 

 of the antheridial cells, the necks alone being free and projecting in a vertical row 

 (Plate IX, figs. 5, 9, and 14). 



In Teratomyces a somewhat similar condition is brought .about through the re- 

 peated sympodial branching of the appendage, the false branchlets (Plate X, figs. 

 6 and 11) being either antheridia or short sterile outgrowths, terminated by a charac- 

 teristic beak-like cell. Although, in this last instance, a regular series of antheridial 

 cells, either alone or mingled with sterile branchlets, is produced, the type is not 

 strictly comparable with that of the previously mentioned instances; in which the an- 

 theridial cells or branchlets originate as a result of the scptation of an axis already 

 formed and the production of monopodial branchlets from the resultant cells. In 

 Teratomyces it is evident that the serial arrangement is necessitated by the relative 

 position of the crowded appendages. 



In the second category may be included all the remaining genera, comprising 

 forms in all of which the simple antheridia are not thus disposed in regular series, 

 but are more or less irregularly placed on the appendages. Although never serially 

 arranged through monopodial branching, individual examples occur, however, in which 

 the grouping of the antheridia is very characteristic and specifically distinctive. 

 Among the instances included in this general category, Laboulbenia is by far the best 

 illustration, since it comprises a greater variety of forms than any other genus. 

 Among those in which there is no definite relation in position between the antheridia, 

 Laboulbenia elongata or L. Plcroslichi may be mentioned, while among forms in which 

 there is a more definite grouping, Laboulbenia variabilis (Plate XXI, fig. 3) or L. pro- 

 liferans (Plate XVII, fig. 23) offer the best examples of more or less regular and dis- 

 tinctly characteristic clusters. Species in which the antheridia are borne in pairs, or 

 are irregularly groirped, are common ; while in one instance, the curious L. zanzibarina 

 (Plate XVII, fig. 3), a single short series may result, as in Teratomyces, from continued 

 sympodial branching. 



In regard to the number of simple antheridia that may occur in individual cases, 

 it may be mentioned that there are often wide differences, not only between different 

 species, but between individuals of the same species. Laboulbenia texana, for instance 

 (Plate XX, figs. 16-18), has one, rarely two, antheridia, while L. elongata may have 

 from five to fifty or more. Wherever fertilization has failed, as not infrequently hap- 



