212 AQUATIC PHYCOM YCETES 



form or ovoid and asymmetrical, strongly arched or re- 

 flexed (anatropous), attached laterally near the narrower 



end P- anatropum, p. 21 7 



Sporangium basally attached, upright, pyriform, obpyriform, 

 ellipsoidal, ovoid or spherical 

 Sporangium obpyriform, haustorium needle-like or peglike, 



mycetophagous P. mycetophagum, p. 217 



Sporangium pyriform, ovoid, oblong-ovoid, ellipsoidal 



Haustorium small and knoblike, formed just beneath the 

 sporangium; the latter symmetrically pyriform, with 



a small papilla P. chlorogonii, p. 218 



Haustorium spherical, formed at the tip of a slender fila- 

 ment arising from the base of the sporangium; the 

 latter pyriform or ellipsoidal with a broad blunt apex 



P. eudorinae, p. 219 

 Sporangium ovoid or spherical 



Haustorium knoblike or discoid; sporangium spherical, 



parasitic on Bumillaria P. bumilleriae, p. 220 



Haustorium a short blunt peglike tube which projects only 

 slightly beyond the inner face of the algal wall 

 Sporangia 10-24 \x in diameter; zoospores 3 \i; in fresh- 

 water algae P. brevipes var. brevipes, p. 221 



Sporangia 20-30 \j. in diameter; zoospores 4-5 y.; in 



marine algae P. brevipes var. marinum, p. 221 



Wall of sporangium wholly or in part deliquescing at zoospore dis- 

 charge and of uniform thickness, or basally thickened and col- 

 lapsing and sometimes fragmenting at zoospore discharge 

 Wall uniformly delicate, completely deliquescing and liberating 



the spores P. piriformis, p. 222 



Wall with a thickened basal portion, collapsing and fracturing at 



zoospore discharge P. tenue, p. 222 



Phlyctidium apophysatum Canter 

 Trans. Brit. Mycol. Soc, 31: 95, fig. 1. 1947 

 "Thallus monocentric, consisting of an extramatrical sporangium 

 [spherical to oval] 9—17 fj. in diameter, an intramatrical apophysis, 

 either spherical, 5 jjl in diameter, or subspherical, 6.7 x 10 [x, never 

 exceeding diameter of the sporangium, continuous with a tubular rhi- 

 zoid (24 ) 7[jl) to (12 3.3(a). Zoospores oval 1.4 x 2.4 u. with a 

 minute colourless globule, and posterior flagellum 13 u. long, discharged 



