1 62 DIVISION II. COURSE OF DEVELOPMENT OF FUNGI. 



very thick, and many-layered membranes, the outer layers of which, the epi- 

 sporium, are coloured and sclerosed in many species, in some are furnished with 

 wart-like or slender spike-like prominences ; they may also be known by their very 

 dense protoplasm containing a large quantity of fatty matter uniformly distributed in 

 small drops or granules, as in species of Synchytrium, or aggregated into a few drops 

 or into one comparatively large round drop, as in Polyphagus, Chytridium Brassicae, 

 Won, Rhizidium mycophilum, A. Br., Chytridium Olla. The resting-spores remain 

 dormant for some time before germinating. 



If we next endeavour to form an idea of the course of development in the 

 Chytridieae, we shall find that our present knowledge permits of our distinguishing 

 four types, which might perhaps be combined by pairs into two main types. Each 

 of these has one or more chief representatives, and each of these again has a crowd 

 of imperfectly known forms doubtfully associated with it. There are no distinctly 

 intermediate forms between the two types. 



FIG. 75. Polyphagus Euglenae. A swarm-spore with sphere of fatty matter and nucleus.. B young plant grown from a 

 swarm-spore with a branch of the rhizoid attached to a resting Euglena e. C zoosporangium with formation of spores just 

 completed and resting on the empty mother-vesicle a (prosporangium) from which it has proceeded ; on the vesicle are three 

 rhizoid-branches. D conjugation ; a the receptive individual, * the supplying individual, s the swollen end of the tube of 

 conjugation connecting a and *, which end is becoming the rudiment of the resting spore, the Euglenae attacked by the 

 Polyphagi. E a portion of the pair shown in D sj hours later than D ; * and s indicate the same parts as in D, * empty, f 

 mature. After Nowakowski. A magn. 550, B, D, E 350, C about 400 times. 



SECTION XLVII. i. Rhizidieae. One species belonging to this section, 

 Polyphagus Euglenae, a parasite upon resting Euglena viridis, has become the 

 best-known of the Chytridieae through Nowakowski's beautiful investigations (Fig. 

 75). The swarm-spore when it has come to rest in the water becomes spherical 

 in shape, and at once puts out hair-like tubular-rhizoid processes in indefinite 

 directions (B]. If one of these encounters a resting Euglena (<?), it penetrates into its 

 body, destroying and exhausting it to supply food to the parasite. The parasite 

 then begins to increase in size, the rhizoid-tubes become larger and thicker, and 

 new ones are formed which throw out branches, and attack and destroy any new 



