84 Dr. F. Cohn on the Development and Propagation 



after. Tlie pcrniination took place still more quickly in sub- 

 sequent third and fourth oxprriim-nts, wherein it occurred in 

 forty-eifrht hours, with spores which up to that time had been 

 kept in the herbarium, I am (piite nuable to exi)hun the enig- 

 matical hasteuiuir of the germination in the spring nu)nths ; it 

 could scarcely have dejiended on the greater heat, for the room 

 was heated to a higher temperature during the winter. At the 

 same time the germination of the Sj//ia'r()j)lea-s])orcs occuiTed 

 relatively rarely in cultivation, so that it went on through many 

 weeks, and the majority of the spores still remained unchanged; 

 while in the natural locality, the ])otato-field above mentioned, 

 by the middle of April, about which time the iield was again 

 flooded, the spores had all germinated, and no trace of the red 

 felted uuiss remained, while the standing water was full of the 

 green filaments of Spharoplea. 



The germination of the spores of Fphfprojden differs from 

 everything formerly known of the develoj)ment of the Algfc and 

 of plants generally ; (m the othf r hand, it agrees surprisingly 

 with siuudtaneous observations on the germination of Bulbo- 

 chate* already published by I'ringsheim in these Reports. The 

 youngest germs of Sp/uerojj/ca that I perceived were spindle- 

 shaped corpuscles from j^^j to yj-g of a line in diameter, and 

 about ^'jj of a line long, running out at both ends into long 

 filiform points which were irregularly carved and twisted, and 

 increased the total length to ^'^ of a line and more. These ger- 

 minating plants resembled in shape, even indistinguishably, 

 that interesting species of Closterium which Ehrenberg has de- 

 scribed and figured as C. rostratum. The contents of the germ 

 displayed every intermediate stage from the red of the spore to 

 the green of the developed plant; the red and green were 

 mingled in a most elegant manner, either with the red oil-glo- 

 bules accumulated at one end and the green chlorophyll at the 

 other, with a colourless band separating them in the middle; or 

 bands of red and green alternated; or the whole contents were 

 green sprinkled with red globules. At first sight of these germs, 

 1 perceived that their dimensions were much smaller than those 

 of the spores from which they nuist have been produced; hence 

 they evidently must have originated from a part, not the whole, 

 of the sjjore. Added to this, I never found a germinating plant 

 sticking in the membranes of the spore, but always scattered 

 free in all parts of the water ; so that I was necessarily driven to 

 the conjecture that these portions must have been discharged 

 from the spores as " swarming-cells." I was soon enabled to 

 confirm my conjectures by direct observation. 



* Ann. Nat. Ilist. Ser. 2. xv. p. 349. 



I 



