CHAPTER V.—COMPARATIVE REVIEW.—CHYTRIDIEAE. I 65 
fatty matter in a finely granular protoplasm tightly packed in a vesicular receptacle, 
which was evidently an intercalary member of a very slender branch filament. The 
spherical cells rich in fatty matter are resting-spores of Chytridium. Aftera long resting 
period (about four months in the cases which have been observed) they germinate and 
put forth a cylindrical germ-tube, which as it grows takes the shortest way to reach the 
outside, piercing through the membranes of the oospore and the oogonium. When its 
extremity has reached the outer surface of the oogonium, it swells into an ovoid spo- 
rangium, which resembles in every respect that which is ascribed to Chytridium Olla. 
It is developed at the expense of the protoplasm of the resting-spore, which passes 
through the germ-tube into the sporangium after the dissolution of the fatty sphere ; before 
this transference has come to an end a transverse wall makes its appearance in about 
the middle of the tube, and the sporangium when fully grown is also delimited from 
the tube by a transverse wall (Fig. 76 A, B). 
So much is matter of observation. The gaps in our knowledge of the details are 
readily descried ; speaking in general terms we may say that the question of conjugation 
and fertilisation is still unsettled, and that the continuity of the development between the 
germinating swarm-spore and 
the filaments which form the 
resting-spores has not been satis- 
factorily established. This latter 
defect would be of very small 
importance in presence of the 
perfect similarity between the 
sporangia developed from the 
swarm-spores of Ch. Olla and 
those from the resting-spores, if 
another form, also a Rhizidium, 
had not been observed in the 
plants examined under cultiva- 
tion, which at least resembles 
Chytridium Olla in the formation 
of the sporangia. The sporangia 
of this species are not as like 
the sporangia developed from withan killed by the parasite; the 
e resting-spores of Chytridium which ripened in October; ‘three of these spores 
the resting-spores as are those areseen still d, two have germinated. By turning the specimen round 
it was seen distinctly that the empty sporangium @ was formed from the rest- 
of Ch. Olla, but they always Te- ing-spore 2’, and the sporangium 4, which is ejecting its contents, from 5; 
semble them enough to make it near the mouth of d are the cast-off lid and two zoospores. 3 an isolated 
rae resting-spore after ination with the i still undivided, from 
necessary to be careful in inter- another speci C resting-spore in a 1 hed to the b 
2 of the filament on which it was formed, prepared from a dead oospore like that 
preting the observed facts. shown ind. A, B magn. 475, C oxo times, 
In conclusion we refer once 
more in this place to the genus Zygochytrium mentioned on p. 156. 

FIG. 76. Chytridium Olla, A. Br. (). A oogonium of Oedogontum rivulare 





Section XLVIII. 2. Cladochytrieae. A delicate much-branched and widely 
spreading mycelium resembling the rhizoids of the Rhizidieae forms numerous 
terminal and intercalary sporangia on its branches, and the germinating swarm-spores 
give rise to a mycelium resembling the original one. The sporangia of many species 
are only known in the form of resting-spores. 
The species first determined by Nowakowski in this group inhabit the decaying 
tissues of marsh-plants and the jelly of Chaetophora. The course described above 
has been directly observed in them from the germination of the swarm-spores to the 
production of the next sporangiferous generation. The sporangia are formed in large 
numbers on the vegetating mycelium and proceed to form their spores at once without 
passing through a period of rest. 
