213 Dr. W. Pringslieiin on the Germination 



the contents are frequently transformed into spores not directly 

 germinating, in spores which had originated through copulation 

 (PI. VIII. fig. 7). They were always however motionless, and I 

 was equally unsuccessful in observing a further development of 

 these cells, and confirming the very natural conjecture of Meyen 

 by direct observation. But I also frequently found the contents 

 of the filament-cells — when no large spore had been previoiisly 

 formed in them — transformed into peculiar cells (Pis. VIII. and IX. 

 figs. 4 & 8), which appear as the mother-cells of smaller moving cells ) 

 and the latter appear to stand in close relation to the development 

 of the Spirogyrce. How far the phsenomenon observed by Agardh 

 agrees with one of these phsenomena, will be seen from the sub- 

 sequent description of my observations. At the same time, the 

 import of the well-known large isolated bodies originating from 

 the entire contents of one or two conjugated filament-cells 

 (fig. 1 a, b, c), as true spores of the Spirogyrce, is not affected by 

 the possibility of a propagation of the Spirogyra by means of the 

 secondary cells originating in the elliptical spores, since in the 

 regular course of vegetation, the fonner, exactly as Vaucher ob- 

 served, exclusively effect the propagation by their direct germi- 

 nation. The dissolution of the contents of a spore capable of 

 direct germination, into daughter-cells equally capable of germina- 

 tion — for which Agardh's observation would speak — as well as 

 the occurrence generally of several different forms of spore in the 

 same plant, appear to me only a result of the independence of 

 the individual cell prevailing in the Algse, and a very general 

 property of these, physiologically speaking, simply unicellular 

 plants. I shall return to this point in speaking of the rare forms 

 of spore of the Spirogxjrce at the conclusion of this memoir. 



I observed the germination of the ordinary form of Spirogijra- 

 spores, those well-known large, elliptical bodies, in Spirogyra 

 jugalis*. Conjugated specimens of this Spirogyra, collected in 

 August, maintained themselves in this condition through the 

 winter, in my room, in a little glass vessel full of water, to the 

 bottom of which they gradually sank. Some spores germinated 

 as early as February, but most of them did not open until April, 

 so that some eight months elapsed between their formation and 

 their germination. We observe in the spores of Spirogyra, as in 

 all motionless spores of Algse, a long period of rest between for- 



* The determination of the name was made with Kiitzing's ' Species 

 Algarum.' — The plant I examined had several, mostly 4, spiral bands ; the 

 septa of its cells were not thrown back in folds (see, in regard to such folds 

 in Spirogyrce, Cohn's Essay in Nova Acta Acad. N. C. xxii. pars ii. 250 

 et seq.). The diameter of the filaments was O'l millimetre; the length of 

 the joints, fertile and barren, varied between 012 and 02 mm. ; some 

 attained a size of 0-3-0'4 mm. 



