136 THE SAPKOLEOlsriACE^ OF THE UNITED STATES 



have received from the herbarium of Prof "W. G. Farlow a specimen from a similar 

 mass, collected in a stream, below a "tripe-house," at Brid<^eport, Conn., by Mr. 

 Isaac Holden. 



The species is easily recognized by the regularly dichotomous branching and 

 rapid reduction in size of its principal hyphae, and by its cylindrical sporangia 

 developed in basipetal succession. While the zoospores ordinarily escape from the 

 sporangia, they sometimes become encysted within them (Fig. 117). It is this fact, 

 probably, which led Braun to state ('51) that the spores oi Leptomitus are arranged 

 in a row in the spore cases, and that " no active gonidia seem to occur." 



The hyphse of this plant are especially favorable for the study of the so-called 

 cellulin grains. Frequently, when a sporangium is formed, its narrow connection 

 with the next segment is closed by the occupation of the passage b}"^ one of these 

 granules. This simple method of forming a cross partition is perhaps not very differ- 

 ent in kind from that which occurs in the Saprolegnieoe. 



Species e^quieend^ aut excludeistd^. 



Many so-called species of this genus have been described by early authors, and 

 may be found catalogued by Ktitzing ('49), and in part by Saccardo ('88). The 

 great body of them are mei'ely sterile, submei-ged hyphse of uncertain origin, and even 

 to list them heie would be useless. The only species which need be mentioned, and 

 concerning which further information is desirable, are : 



Leptomitu? Libertioe (Bory) Ag. ('24) [Exsic, Libert, Plantes Crypt, Ard., 97], 

 placed doubtfully by Saccardo ('88) under Saprolegnia. The published description 

 mentions no reproductive organs and I have not been able to examine liibert's exsic- 

 cata. So far as the description goes, the plaut may belong to this family, but probably 

 rather to the Soprolegniem than to the present subfamily. 



Leptomitus ruhescens DeBreb. [Exsic, Algues de la France, 30(5], and 



LejJtcmitus Dorice Ces, [Exsic, Rabh.,Algen Sachsens, 575] are mentioned only 

 in the quoted exsiccatce. They will probably prove to be only sterile hyphse. 



Apodaclllya Pringsh. ('83b). 



Hypha? slender throughout, marked off at intervals by constrictions into distinct 

 segments ; branching monopodial ; branches arising fi-om any part of a segment. 



