ON THE GERMINATION OF CHAEA. 299 



difficult of access to a great many readers.^-' To the observations 

 here communicated, which were concluded in the year 1872, a few 

 corrections, based on the investigations of Mr. Kamienski, a student in 

 the laboratory at Strassburg, have been added. 



In the first place, it should be stated that the material for exami- 

 nation was partly accumulated in continuing the researches on the 

 development of the ovule-buds, and the mode of impregnation of the 

 Characem,] and partly in some investigations undertaken to elucidate 

 more fully the evolution of parthenogenesis in Chara crinita^X ^^- 

 specting this phenomenon, the examinations revealed the fact that 

 the ovule-bud originates in precisely the same positions, and its 

 development is exactly as in the other monoecious and dioecious species 

 of the genus ; further the neck parts into five clefts before ripening, 

 as in other Charas before impregnation. These clefts are indeed small, 

 though not smaller, for instance, than in C. scoparia. Moreover, it 

 was most satisfactorily demonstrated that the ripening of the oospores 

 of isolated female plants under continual control neither showed any 

 trace of antheridia, mr were there any antheridia-bearing plants 

 near them. It may be asserted without exaggeration that under good 

 culture scarcely a single oospore fails to germinate. The female plant 

 growing wild is more fertile than any of its congeners, although the 

 male plant, with the exception of some herbarium specimens men- 

 tioned by Braun, is unknown. Finally, it was proved that the 

 oospDres matured on isolated female plants under the most perfect 

 control would germinate. Ripe oospores were taken on IS'ovember 10 

 from plants isolated on the 9th of the preceding July. They ger- 

 minated at the beginning of April, and produced normal plants, and in 

 many instances the first whorl of the primary stem bore oospores. 

 The difi'erent phases of germination in these unimpregnated oospores 

 are exactly like those in the sexually produced oospores of other 

 species. Of the actual occurrence of parthenogenesis in this plant no 

 shadow of doubt can exist. 



To proceed to the phenomena of germination, the structure of the 

 ripe oospore and its shell or envelope should be first considered. The 

 oospore, it will be remembered, consists of a cell with a moderately 

 thick, colourless cellulose wall, uniformly filled with colourless fat 

 and grains of starch. It is perfectly closed all over by the thick 

 usually brown shell, which is developed after impregnation from the 

 continuous walls of the cells enclosing it, these portions of the cell- 

 walls thickening and hardening, while the other parts of the walls 

 first rise as a jelly, and afterwards, together with the contents, melt 

 and disappear. In all cases, the uninterrupted inner wall of the five 



* Supplementary note. — Even after the appearance of Nordstedt's and Wahl 

 stedt's more recent communication {blora, 1875, No. 6), an account of my 

 labours may not be altogether useless ; and therefore I have had it printed with- 

 out altering it much from what was jotted down three years ago, and as I sent 

 if off a few months back. The observations on Nit. tenuissima alone have been 

 extended. (April 20, 1875.) 



t Compare " Monatsber. der Berliner Akademie," Mai, 1871, and "Botan- 

 ische Zeitung," 1871, p. 871. 



X On this subject consult Al. Braun, ''Parthenogenesis," "Abhandl. der 

 Berl. Akademie," 1856, p. 337. 



