CHYTRIDIALES 441 



colorless wall, the inner face somewhat irregularly thickened (wavy), 

 the outer face smooth, 22-30 \i broad, with a short broad apical papilla; 

 rhizoids dichotomously branched or unbranched, 1.5 \i in diameter, 

 polyphagous, the endobiotic ones often running for some distance 

 parallel with the axis of the alga; zoospores narrowly ovoid with a broad 

 apex, 5-6 u. long by 3-3.5 u, broad, with one flagellum and one or more 

 colorless globules in the contents, upon discharge resting temporarily 

 in a mass in front of the orifice before swimming away, movement 

 swimming or hopping; resting spore (?) formed by contraction of the 

 contents of a sporangium-like structure, spherical or somewhat angular 

 with rounded corners, 13-17 \x in diameter, with a thick colorless 

 smooth wall and from one to two large globules, germination not 

 observed. 



On Tolypothrix lanata, Germany. 



The somewhat angular resting spores, formed in the autumn, unlike 

 those of other species in the genus rested loosely in a sporangium-like 

 structure. 



Zukal mentions another inhabitant of Tolypothrix which forms a 

 broad curving filament in the alga. He suggests tentatively that it might 

 be Myzocytium, but it may possibly be Rhizosiphon or Lagenidium. 



Rhizophlyctis rosea (de Bary and Woronin) Fischer 

 Rabenhorst. Kryptogamen-FL, 1 (4): 122. 1892 



Chytridium roseum de Bary and Woronin, Berichte Verhandl. Naturforsch. 



Gesell. Freiburg, 3 (2): 52, pi. 2, figs. 17-20. 1865. 

 Rhizophydium roseum de Bary and Woronin, loc. cit. 

 Kar/ingia rosea (de Bary and Woronin) Johanson, Amer. J. Bot., 31 : 399, 



figs. 1-37. 1944. 



Explanation of Figure 28 



A-D. Rhizophlyctis petersenii Sparrow: A, mature thallus, discharge tube 

 beginning to form; B, mature sporangium with discharge tube; C, 

 sporangium immediately after discharge, the zoospores, each with a small 

 orange-colored oil globule, forming a motionless spherical cluster at tip of 

 discharge tube; D, ellipsoidal resting spore formed just beneath wall of integ- 

 ument. E-G. Rhizidium verrucosum Karling, stages in the discharge of the 

 zoospores from zoosporangia. 



(A-D, Sparrow, 1937a; E-G, Karling, 1944c) 



