138 THE SAPEOLEGlsriACE.E OF THE U^flTED STATES, 



Louisiana — St. Martinville, Langhis.. 



This very interesting plant affords the first recorded instance of the occurrence 

 of sexual organs among the LeptomitecB, unless the imperfectly described 8. (Leptomitus) 

 corcagiensis of Hartog be such an example. The latter cannot, however, be the same 

 form as the present one. This plaiit appeared in very limited quantity on a fly which 

 had been thi-own into an old and feeble culture of Saprolegma sp., obtained by 

 Rev. Mr. Langlois from a ditch in St. Martinville, La. The moribund condition of 

 the culture when it was received caused these freshly added flies to decay so much 

 that the development of other Sa2)rolegmeoe was slight and unhealthy ; but the few 

 plants of this form were developed normally and seemed to find their surroundings 

 congenial, indicating that it, like L. Jacteus, is partial to polluted waters. 



A very careful and detailed examination of the material failed to discover any 

 sporangia, and it does not, therefore, certainly belong to the present genus. But, 

 since the hyphse are certainly not those of L. lacteus, but are slender throughout, 

 branch monopodially from all parts of their rather long segments, and in general 

 resemble strikingly those of Apod, pyrtfera, it is placed provisionally here. 



Its great interest lies, as before suggested, in its possession of well-formed 

 sexual organs of peculiar and chai'acteristic structure. The oogonia are globular and 

 are formed by the swelling of the terminal segment of a branch. When young, they are 

 filled by granular protoplasm which is entirely used up in the formation of the 

 oospheres, a fact which confirms our previous belief that these plants belong to the 

 present family. The narrow connection between the oogonium and the next segment 

 below it becomes quite solid, and the apical end of the latter segment is usually 

 somewhat swollen and gives rise to the, commonly two, antheridial branches. The 

 oospores, when mature, are quite thick-walled and of uniform and moderately granu- 

 lar appearance (Fig. 120). 



The antheridial bi'anches are composed of one or two cylindrical segments each, 

 and are at first uniformly filled with protoplasm and applied to the oogonium (Fig. 

 119). Later, a part of a segment may be cut off by a transverse wall (Fig. 120), 

 and then apparently constitutes an antheridium. The part cutoff in Fig. 120 will be 

 seen to be quite empty, and similar cases are frequent ; but I have never been able to 

 recognize fertilization tubes homologous with those of the SaproUgmece. On the 

 other hand, the whole segment may become nearly or quite emptied, as show^ n in the 

 right hand branch in Fig. 121. The left hand branch in the same figure shows a 

 condition observed in a number of instances, which is one of much interest. The 

 limited material at hand did not permit extended observations as to its significance, 

 but the facts appeared to be as follows in all of the several similar specimens ob- 



