112 



The following is a summary of Rostafinski and Woronin's researches 

 on this germs : 



If a plant be placed in water, its contents become modified at the 

 latter part of the day or at night into zoospores. Ultimately the wall 

 swells, then bursts somewhere at the top, and the zoospores resulting 

 from the division of the parietal stratum escape. If the plant be only 

 moistened, the zoospores do not swarm out, but come to rest within the 

 collapsed wall. Such were known to previous observers as " germ 

 cells " or " gonidia." 



The zoospores are elongate-oviform, 5-8 X 20 mm., with a single 

 flagellum, and 2 to 4 chlorophyll granules. Having swarmed out, they 

 soon come to rest, lose the flagellum, become surrounded by a mem- 

 brane, increase in size, and germinate on clamp earth, in which stage 

 they represent the so-called Protococcus botryoides. 



The large ordinary zoosporangia are also otherwise modified. If one 

 is allowed to dry, its membrane collapses, loses colour, and soon becomes 

 empty. The protoplasmic contents pass down to the ramifications of 

 the root. Here they break up into numerous cells, sometimes two or 

 thi'ee side by side, but chiefly in a continuous chain ; each cell furnished 

 with a separate membrane. 



These are capable of three forms of development: (1) If removed 

 from the soil and placed in water, the cell becomes a subterranean 

 zoosporangium. The formation of the zoospores is independent of light 

 at any hour of the day or night. The zoospores are similar to those 

 above described, and germinate in the same manner. (2) If a chain of 

 these root cells be laid on moist earth, each protrudes a hyaline process, 

 which enters the soil, the opposite end being elevated, and thus each 

 root cell becomes a vegetative plant. (3) If the root cells are not 

 removed, and kept equably moist, they also germinate in the earth, 

 become inflated, put forth a root process, the wall of which becomes 

 very much thickened on the inner side below the inflated upper portion. 

 By interculary growth of the root portion the upper part becomes raised 

 aloft, so that the apex is carried above the surface of the soil. These 

 products of modified root cells are named hypnosporanges, and are equi. 

 valent to so-called Botrydium Wallrothii. When dried, the hypno- 

 sporanges retain their power of germination during the whole year, and 

 when placed in water form zoospores at any hour of the clay and night, 

 germinating and forming young plants as above, 



The uniflagellate zoospores germinate on a moist substratum. On 

 earth or sand they thrive badly, but better 011 clayey or muddy soil. In 

 water they never germinate, but come to rest, are surrounded by a 

 double membrane, and lie dormant for months. If these be transferred 

 upon a clayey soil, they commence to form a vegetative plant. If the 

 zoospores be sparingly distributed over the soil, and the whole kept 

 equally moist, the vegetative plants become ordinary zoosporanges. The 

 plants are sometimes modified into hypnosporanges. 



Thus, vegetative plants can be increased by cell division directly 

 from zoospores, become ordinary zoosporanges, with such consequences 

 as root cells, &c., or they may be directly modified into hypno- 

 sporanges. But there is yet another way in which existence may be 

 carried on. If exposed to drought, the following phenomena occur: 

 The wall collapses more or less, and the protoplasmic contents break up 

 into a number of cells, each surrounded by a delicate membrane, its 

 contents homogeneous, at first green, then passing into red. These are 

 the spores, and have been known by such names as Protococcus coccoma, 

 P. palustris and P. botryoides. These spores become changed in water 

 to zoosporangia, their contents giving rise to zoospores in the manner 

 already described. If the spores be still green, their zoospores will 

 have a distinct fusiform figure, with two cilia at one end. They consist 



