302 



BOTANY. 



some cases at least, when free from the lichen-thallus, by 

 the production of zoospores. 



Their connection with the hyphan is sometimes by the 

 prolongation of a short branch from the latter, which passes 

 to each gonidial cell (Fig. 208) ; in other cases the connec- 

 tion is with one cell of a row, as in Plectospora,* where the 

 connection may be with the terminal cell of the row, or with 

 any of the intermediate ones ; in either case, the cell to 

 which the hypha-branch is attached is considerably larger 

 than the others in the row. Schwendener describes! a con- 



FIG. 208. 



FIG. 209. 



Fig. 208. Gonidia of different lichens, a to , of Parwrlia titiacea, showing a, 6, 

 and e, the attached hyphu-, X 390 ; A of Usnea barbata. with attached hypha, X 

 700 ; g, of Sphcerophor'us globiferiis, with attached hypha, x 390. After De Bary and 

 Schwendeiier 



Fig. 209.-Gonidia. a, a, of Lecanactis illecebrosa ; b, l>, of Qraphis swipta. 

 After De Bary. 



nection which he has seen in certain gelatinous lichens, in 

 which two and three short branches pass off from the same 

 hypha, and unite with the cells of one gonidial chain. 

 TronbJ confirms Schwendener's statement, saying that he 



* See De Bary's " Morphologic und Physiologic der Pilze, Flechten," 

 etc., p. 264. 



f " Die Flechten als Parasiten der Aljren," 1873. 



j Dr. Melchior Treub, " Onderzoekingen over de Natuur der Liche- 

 nen." 1873. 



