CHYTRIDIALES 131 



Sporangium subspherical or broadly ellipsoidal, its long axis 

 parallel with that of the algal cell; discharge tube arising 

 from the middle of the sporangium, thus appearing 

 lateral, with a pronounced endobiotic swelling; in Con- 



jugatae O. endogenum, p. 132 



Sporangium spherical, ellipsoidal, ovoid, or pyriform, endo- 

 biotic part of the apical discharge tube isodiametric; in 

 various green algae 

 Sporangium spherical, ellipsoidal, or ovoid, resting spore 

 smooth-walled 

 Sporangium spherical, discharge tube not projecting 

 beyond outer surface of the algal wall; in Zygnema 



O. ZYGNEMICOLA, p. 134 



Sporangium spherical, ellipsoidal, ovoid, or occasion- 

 ally somewhat pyriform, discharge tube project- 

 ing more or less beyond wall 

 Discharge tube strongly constricted when passing 

 through host wall, expanded locally on outer 

 surface and extending extramatrically ; in zygo- 

 spores of Spirogyra O. rostriferum, p. 134 



Discharge tube isodiametric, extending for varying 

 distances beyond algal wall 

 In vegetative cells of various green algae 



O. ENTOPHYTUM, p. 135 



In oospores of Sphaeroplea ... O. sphaeropleae, p. 137 

 Sporangium pyriform, with a short sessile discharge tube, 



resting spore spiny; in Hyalotheca O. hyalothecae, p. 137 

 Sporangium tubular or saclike; in desmids 



Sporangium swollen and short sausage-like or saclike, con- 

 stricted in the mid-region O. saccatum, p. 138 



Sporangium a complex of branched tubes, without con- 

 strictions O. utriculiforme, p. 139 



In Euglenophyceae ; sporangium spherical; zoospores formed in 

 an extruded vesicle as well as in the sporangium 



O. euglenae, p. 139 

 In diatoms; sporangium spherical, 3.4-5.5 \x in diameter, opening 



by a pore; in Hantzsclria O. hantzschiae, p. 140 



In plant spores 



In pollen grains; sporangium spherical or ovoid; discharge 



tube short or long 



Sporangium spherical, generally with a short broad discharge 



tube; zoospores spherical, 4-5 u. in diameter; penetration 



tube often persistent on the smooth-walled resting spore 



O. pendulum, p. 140 



