584 AQUATIC PHYCOMYCETES 



in that it is endobiotic and the sporangium has a discharge tube. Both 

 of these are variable characters and of questionable taxonomic worth 

 in distinguishing species. The form called TV. endogena by Domjan 

 (1936: 51) appears from the character of its resting spores more nearly 

 related to N. ramosa. 



Thick-walled spherical or ellipsoidal apophysate colorless resting 

 spores with fatty contents were associated with the sporangia in the 

 British material. From the fact that they were borne on a polycentric 

 rhizoidal system it is possible that they may belong to the species, but 

 further observations are necessary to determine this point with certainty. 



The three following species appear to be indistinguishable from 

 Nowakowskiella elegans except for regular formation of resting spores. 

 No striking and significant unvarying characters of thallus, sporangia, 

 zoospores, or resting spores separate them from that species and the 

 sizes of parts intergrade. Until the limits of variation of the rhizoidal 

 systems of the species are established, it cannot be said what reliance 

 can be placed upon them for differentation at the species level. The 

 situation is further complicated by the fact that while Karling, the 

 author of two of these species, has reported N. elegans many times, he 

 has never described or figured his conception of it. Since, however, 

 future observations may clearly indicate the limits of N. elegans and 

 prove that the three are distinct from it, their descriptions are given 

 here and they are not placed in synonymy. 



? Nowakowskiella delica Whiffen 



J. Elisha Mitchell Sci. Soc, 59: 37, pi. 2. 1943 



"Rhizomycelium, intra- and extramatrical, much branched with 

 numerous elongated swellings, which give rise to zoosporangia or 

 resting bodies. Zoosporangia, terminal or intercalary, 12.5 x 15.0 u. to 

 22.5 X 28.8 \i, spherical, ovoid, or pyriform; with a single exit pore, 

 usually laterally but often apically placed, operculate; apophysis var- 

 iable in shape, 2.5 X 15.0 a to 1 1.5 x 17.5 [i. Zoospores hyaline, spher- 

 ical, 5.7-7.5 \i, posteriorly uniflagellate, flagellum 30 [j. long, unigut- 

 tulate. Resting bodies, terminal or intercalary, usually intramatrical, 

 ovoid to spherical, 10.0 < 15.0 [a, to 26.2 x 29.9 [x, apophysate, hyaline, 



