292 Dr. \y. Pringshtim on (he Germinnfiun 



XXVIII. — On the Germination of the Resting Spores, anM'M^ 

 form of Moving Spores in Spirogyra. By Dr. W. PlilW<^- 



HEIM*. ' "■■'' 



[Concluded from p. 218.] ' "^' 



■)i' 



[With two Plates.] - .13 



I NOW pass to the account of those structiu-es which I have 

 found in the spores, and certain others met with in the filanaent- 

 cells of Spirogyra', and of which I presuppose that they likewise 

 serve for the reproduction of the Spnrogyra. The same, or 

 some phsenomena similar to those I have detected, probably led 

 Agardh to the idea that the large spores became broken up into 

 zoosporesf. 



I have little to add to what has been stated at page 211 con- 

 cerning the secondary cells originating in the spores from their 

 contents. The transformation of the contents of the spores into 

 these cells is by no means rare. They present either the appear- 

 ance shown in fig. 7, of little round cells with granular contents, 

 or, as MeyenJ represented them, of similar cells, but with con- 

 tents consisting only of one single homogeneous grain, almost en- 

 tirely filling the cell. I have not been able to detect movement 

 or germination in them. 



The structures existing in the filament-cells are more inter- 

 esting. I frequently found, namely, in conjugated filaments, 

 that the contents of one or more pairs of conjugated cells were 

 not transformed into the well-known large spore. But while in 

 unconjugated cells, in which no spore was produced, the contents 

 became decomposed, exhibiting a disappearance of chlorophyll 

 and simultaneous appearance of a red-brown colouring matter, 

 in perfectly indefinite although here and there granular forms 

 (PI. VIII. fig. 1 o), the contents of such conjugated filament-cells 

 as produced no solitary spore, becanae ti-ansformed into a num- 

 ber of little cells of regular, definite and unchangeable form 

 (PI. VIII. fig. 4). This regular occurrence led me to conjecture 

 that these cells were more than mere pseudo-forms of decaying 

 cell-contents. I first obtained an insight into these structures 

 by observation of their production in the cells of the young Spi- 

 rogyrce, which I had myself seen emerge from large spores. In 

 the cells of these young Spirogyra the existing spiral bands are 

 often broken up, and from their substance are formed, in a man- 

 ner still unknown to me, little cells in which a membrane can be 



* From the 'Flora,' Aug. 14th and 21st, 1852: translated by ArtL'ur 

 ' Henfrev, F.R.S., F.L.S. '''■ 



t Vide p. 211, note ||. 

 \ Pflanzenphysiologie, iii. pi. 10. fig. 13 c. A, e. 



