1920] Setchell-Gardner : Chlorophyceae 299 



which branch rather frequentlj^ and which are comparatively loosely 

 coalescent; P. consociata, with indistinctly radiating basal filaments 

 closely coalescent; and P. applanata, with a parenchymatous basal 

 layer. 



32. Pseudopringsheimia Wille 



Thallus cushion-shaped, epiphytic, often penetrating the hosts at 

 intervals, or growing upon the shells of mollusks ; increase in diameter 

 produced bj^ terminal growth of radiating filaments branching fre- 

 quentl}^ and coalescing to form a parenchymatous basal layer ; increase 

 in thickness produced by horizontal divisions of the cells of the basal 

 layer forming a mass of erect filaments sometimes branching in turn ; 

 cells without hairs containing one chromatophore in the outer end, 

 and one pyrenoid ; zoosporangia mostly terminal on the erect filaments 

 or occasionally subterminal as well. 



Wille, Nachtrage, 1909, pp. 88, 89. 



The genus Pseudopringsheimia was founded on the two species, 

 Ulvella con flue ns Rosenv. and U. fucicol'a Rosenv. The particular 

 characteristic separating the genus, especially from Pseudulvella Wille 

 is the presence of rhizoidal outgrowths from the base penetrating the 

 host plant. In other respects the species of Psevdopririgsheimia closely 

 resemble those of Pseudulvella. It is a question as to how important 

 such structures as penetrating rhizoids should be estimated as being 

 in separating genera, but since Wille has separated the two genera 

 and since we have altogether too little knowledge of their reproductive 

 processes, it seems best to recognize both for the present. 



Pseudopringsheimia apiculata S. and G. 



Plate 17, iigs. 1, 2 



Thallus minute, 145-160/^ thick, hemispherical when alone, but 

 often with manj- crowded closely together forming a continuous 

 stratum 2-3 mm. diam. ; color bright green; erect filaments 8-12/^ 

 diam., composed of 9-12 cylindrical or slightly swollen cells; rhizoids 

 aggregated into short- conical fascicles ; zoosporangia ( 1 ) producing 

 8 zoospores, terminal, slightly swollen, varying from convex to de- 

 cidedl}' apiculate; zoospores (?) 4-ciliated. 



Growing on the rhachis and the cysts of Egregia Menziesii. Cen- 

 tral California. 



Setchell and Garnder, Phyc. Cont. I, 1920, p. 297, pi. 22, figs. 1, 2. 



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