284 



ALG^ 



gelatinous walls. In this condition it was formerly described as a 

 distinct organism under the name Gongrosira. These gongrosira-cells, 

 when isolated, develop into ordinary plants ; or sometimes their proto- 

 plasm breaks up into fragments which escape from the cell-wall and 

 move about with an amoeboid motion. These invest themselves after 

 a time with a cell-wall and remain in this condition as spherical resting- 

 cells or hypnospores, finally developing into ordinary filaments. Wille 

 has, however, shown (Bot. Centralblatt, vol. xvi., 1883, p. 162) that 

 the organisms formerly grouped under Gongrosira are states of algse 

 belonging to a number of widely separated genera, such as Trentepohlia. 



(Chroolepus), Botrydium, Stigeoclo- 

 nium, &c. In some species of Vau- 

 cheria the filaments have a tendency 

 to branch copiously at the extremity, 

 the branches interweaving into a 

 ball. Several species are liable to- 

 the formation of singular galls caused 

 by the attacks of a rotifer belonging 

 to the genus Nptommata (Benko, 

 Bot. Centralbl., vol. xiv., 1883, p. i). 

 Phyllosiphon (Kiihn) is a truly- 

 parasitic chlorophyllous alga occur- 

 ring in the south of Europe within the 

 leaves of Arisarum vulgare, the posi- 

 tion of which appears to be near this 

 family. The single -cell contains a 

 large number of nuclei ; the mode of 

 reproduction is unknown (Kiihn, Sitz- 

 ber. Naturf. Gesell. Halle, 1878 ; Just, 

 Bot. Zeit., 1882, p. 2 et seq. ; Schmitz, 

 id., 1882, p. 523 et seq. ; Franke, 

 Jahrber. Schles. Gesell., 1883, p. 195). 

 Endodonium (Franke) (Cohn's. 

 Beitrage, 1883, p. 365), Chlorochy- 

 trium (Cohn), Endosphcera (Klebs), 

 and Phyllobium (Klebs) (Bot. Zeit, 

 1881, p. 249 et seq.) are green parasitic algse found within the cells of the 

 leaves of various land and aquatic plants ; and, in the case of Chloro- 

 chytrium, also on animals (Bot. Zeit., 1885, p. 605). They are stated ta 

 produce megazoospores, which germinate directly, and microzoospores- 

 or zoogametes, which germinate only after conjugation ; but their exact 

 position is altogether uncertain. 



Fig. '2^.— Botrydium granuiatum Wallr. 

 s. vesicular portion ; w, rhizoids ( x 30). 

 (After Woronin.) 



