198 



Chlorophycew 



growing endophyte. The anomalous habit of these Algae is 

 explained by the protection afforded by the intercellular spaces of 

 the host. Freeman 1 has suggested that the condition of affairs 

 met with in Chlorochytrium lends itself to the development of 

 parasitism and that the allied genus Phyllobium is progressing in 

 that direction. 



Genus Chlorochytrium Cohn, 1874. The cells are generally 

 solitary, globose, ellipsoid, ovoid, or irregularly curved and lobed, 



Fig. 79. A, Vegetative cell of Chlorochytrium Lemna Cohn, from Frizinghall, 

 W. Yorks. ( x 475). B D, Centrosphcera Facciolace Borzi ; B and C, from 

 near Senens, Cornwall ( x 475) ; D, showing escape of zoogonidia (after Borzi, 

 x 410). 



and they contain a large parietal chloroplast furnished with many 

 pyrenoids. Both starch and oil are often found in the cells. 

 Zoogonidia are formed by successive bipartitions of the cell- 

 contents, at first by perpendicular, and afterwards by radially 

 disposed walls. Gametes arise in a similar manner, and conju- 

 gation takes place within the vesicle formed by the protrusion of 

 the inner layer of the gametangium. Some of the species of this 

 genus are endophytes in the leaves of Lemna, Mentha, Rumex, 

 Lychnis, Sphagnum, etc., and others are marine, occurring in the 

 thalli of various marine Algae. 



Chi. Lemnce Cohn occurs frequently in the leaves of Lemna trisulca ; diam. 

 cell. 40 143 p ; fig. 79 A. Chi. Knyanum Szymanski is found on the leaves 

 of Lemna minor and L. gibba. 



The genus Stomatochytrium Cunningham (1888) differs from Chlorochytrium 

 mainly in the absence of the vesicle which surrounds the gametes in the 

 latter genus. This feature can scarcely be regarded as a generic difference. 



1 Freeman, 'Obs. on Chlorochytrium,' Minnesota Botan. Studies, vol. ir, 

 part in, p. 198. 



