CHYTRIDIALES 243 



Rhizophydium karlingii, sp. nov. ] 

 (Fig. 17 A, p. 228) 



Sporangium sessile, spherical, 9-18 [jl (13.5 [x av.), slightly flattened 

 and oval, occasionally bearing a portion of the unexpanded zoospore 

 cyst, with one to three discharge papillae, the single ones for most part 

 being sublateral or near the base, others subapical, lateral or rarely 

 apical, wall smooth, very thin, 0.8-1.7 \x in thickness; endobiotic part 

 usually consisting of a knob- or peglike structure 4-12 \x long by 4 \x 

 in diameter, sometimes distally inflated, rarely tapering, which may 

 pierce the wall and from the tip of which a delicate branched rhizoidal 

 system of variable extent emerges; zoospores nearly spherical, 2.5-3.2 \x 

 in diameter, with a small refractive basal globule and flagellum 12-15 \x 

 long, emerging upon the deliquescence of one or more discharge pa- 

 pillae through an orifice 3-5 \x in diameter; resting spore oval, slightly 

 oblong or spherical, 8-15 [i in diameter, yellowish to amber in color, 

 sometimes bearing a portion of the unexpanded zoospore cyst, smooth- 

 walled, contents without a conspicuous oil globule, germination not 

 observed. 



Parasitic on Ulothrix zonula, United States. 



The species is based on the fungus described by Karling (1938e) 

 as Rhizophydium laterale (Braun) Rabenh. (see Phlyctidium laterale, 

 p. 213). 



Rhizophydium deformans Jaag and Nipkow 

 Berichte Schweiz. Bot. Gesell., 61 : 483, pis. 1 1-12. 1951 

 Sporangium sessile, spherical or elongate, surrounded by the ellip- 



1 Rhizophydium karlingii sp. nov. (R. laterale Karling [1938e], non R. laterale 

 [Braun] Rabenhorst. Vide, p. 213.) — Sporangium sessile, subglobosum, 9-15 u. (med. 

 13.5 [j.), minime applanatum vel ovoideum, interdum partem cistae zoosporae inexpan- 

 sae ferens, papillis efferentibus 1-3, singulis prope basem vel lateralibus, ceteris subapi- 

 calibus, lateralibus vel raro apicalibus; membrana laevi, tenui (crassitie 0.8-1.7 u,). 

 Pars endobiotica bulbiformis vel raro radiciformis, interdum membranam trans- 

 currens, apice ramosis, ramis tenuissimis rhizoidalibus plus minusve extensis. 

 Zoosporae subglobosae, diametro 2.5-5.2 u., globulo basali parvo refractivo et 

 flagello praeditae, deliquescentia unae vel plurium papillarum efferentium per 

 orificia 3-5 [J. diametientia. Spora perdurans ovalis, suboblonga vel rotunda, 8-15 \l 

 diam., flavescens vel luteola, interdum partem cistae zoosporae inexpansa ferens, 

 tenuiter circumvallata, laevis, sine globulo conspicuo oleaginoso; germinatione 

 nondum observata. 



Parasitica in cellulis Ulothricis zonatae, United States. 



