210 Dr. W. Pringsheim on the Germination 



XX. — On the Germination of the Resting Spores, and on a form 

 of Moving Spores in Spirogyra. By Dr. W. Pringsheim*. 



[With two Plates.] 



While the observations on the conjugation of Spirogyrce, first 

 made by 0. F. Miillerf, have since been frequently repeated and 

 are now universally known, the germination of the spores pro- 

 duced through the conjugation, first seen by Vaucher J in 1803, 

 has been confirmed only by very few subsequent observations. 

 Considering the active interest which has recently prevailed in 

 regard to the development of the Algae, and has existed respect- 

 ing the formation of the spores of Spirogyra itself, in a wider 

 circle than that which merely includes algologists, the above 

 fact is the more remarkable, since it is by no means difficult to 

 procure the material required for the investigation ; for although 

 conjugation takes place most frequently in spring, I have found 

 Spirogyr<e both in a. state of conjugation and preparing for it 

 throughout the summer and until late in autumn. Never- 

 theless, so far as I know, there exist only three publications on 

 the germination of the Spirogyra, exclusive of course of all those 

 which do not rest on original observations §. 



The first, as already mentioned, was furnished by Vaucher, to 

 whom we must always go back, when we are studying the deve- 

 lopment of the freshwater Algse. He gave a representation of 

 the germinating spores correct in all essential points, but not 

 adequately good and accurate for the demands of our own day. 

 These figures || are all botanical literature possesses. The essen- 

 tial part of his description of the germination is as follows : " The 

 spores open at one end, like the cotyledons of a seed when its 

 embryo is beginning to unfold, and the young plant emerges as 

 a small, rapidly-growing green sac, in the interior of which the 

 spiral bands, with thin shining granules (the starch-granules) 

 and septa, soon present themselves. Finally the young plant 

 leaves the envelope in which it originated, grows up in the water 

 and then resembles the parent plant, excepting that its two ends 

 are attenuated to points, and that it is of smaller size.^' 



Meyen confirmed these observations. In one essay, indeed, 

 which he wrote on the genus Spirogyra in 1827, he held Vau- 

 cher's observations on the germination of Spirogyra to be false. 



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

 Henfrey, F.R.S., F.L.S. 



t Flora Danica, tab. 883. 



X Histoire des Conferves d'Eau douce ; Geneve, 1803. 



§ See Rev. W. Smith, ' On the Germination of the Spores of Conjugate,' 

 Annals of Nat. Hist. ser. 2. viii. 480. — A.H. 



II L. c. tab. 4, 5, 6. 



