J. BURTON ON BOTRYDIVM GRANULATUM (l.) GREV. 211 



over an extensive area. Perhaps the solution of the problem 

 may be found in the method of reproduction. We learn that it 

 has a remarkable variety of ways of increasing in numbers. 

 Dr. Cooke enumerates about seven or eight, with about five 

 varieties, but there is a doubt about the correctness of some 

 of the observations, and, after all, they may be reduced to about 

 four. In the first place, what we may call proliferation takes 

 place as in almost any of the lower plants. A branch grows 

 from the upper part of a root and turns upwards to the surface, 

 there develops a little swelling, which afterwards becomes a 

 separate individual. The most usual and the most prolific 

 method is for the whole plant to become a zoosporangium. The 

 contents divide up into innumerable little round bodies, each 

 containing several chlorophyll corpuscles. If now the plant 

 is submerged it bursts, and the zoospores swim out with the 

 aid of a cilium. They have a provoking habit of doing this 

 during the night or very early morning, so that it is difficult to 

 witness the process under ordinary circumstances. If the plants 

 are situated on ground only moderately wet, they collapse, the 

 wall sinks in, no doubt because the watery protoplasm passes 

 into the root, and a little heap of spores remains on the surface 

 surrounding the hole which had contained the root. By far 

 the larger number of my specimens went this way, and after 

 leaving them for several weeks protected from complete desicca- 

 tion they remained in the same condition. 



Should a mature Botrydium meet with unsuitable conditions 

 above ground while the spores are still unformed, the whole 

 of the protoplasm may retire into the root-portion. Here 

 it breaks up, each fragment surrounding itself with a rather 

 thick wall, and becomes a hypnospore. This may develop in 

 various ways. Dr. Cooke, translating from a foreign author, 

 says : " If removed from the soil and placed in water the cell 

 becomes a subterranean zoosporangium," which does not seem 

 a very clear statement. Or, if a chain of these cells be laid 

 in moist earth, each protrudes a hyaline process which enters 

 the soil, the opposite end becomes elevated and develops into 

 a fresh plant. He also says that when dried these hypno- 

 sporangia " retain their power of germination for a year, and 

 when placed in water form zoospores at any hour of the day 

 or night." The zoospores first spoken of germinate on a moist 



JouRN. Q. M. C, Series II. No. 68. 15 



