INTRODUCTION. 21 



little time afterwards, the same tufts again have given me 

 Vaucheria hamata, V. geminata, &c. The appendages 

 that Vaucher regarded as the corpuscles, and which served 

 him to establish his species, are very different from true 

 spores by the thickness of their envelope, and by the nature 

 of their contents. Crushed under the microscope, they 

 permit drops of a very refracting liquid to escape, which 

 alcohol dissolves not, but of which it renders the green 

 colour more brilliant. Sulphuric acid causes it to change to 

 a clear fawn, and iodine to brown. It is true that these 

 appendages are formed, like the spores, by the condensation 

 of the green matter, and that they are separated from the 

 mother plant by a diaphragm ; but I have never found them 

 but upon filaments which have begun to disorganize them- 

 selves, and almost always they decompose with them. Now, 

 since I have constantly gathered in the same locality all the 

 individuals of Vaucheria which have served for my observ- 

 ations, and since I have seen them take successively all the 

 forms represented in the annexed plates, I believe that I 

 ought to unite Vaucheria ovata, clavata, sessilis, hamata, 

 terrestris, geminata, ccespitosa, cruciata, into a single species, 

 which I propose to designate under the name of Vaucheria 

 Ungeri) in remembrance of the learned work of the German 

 author and his interesting discovery. 



We have examined four different types of locomotive 

 organs in the spores of the Alg& : analogous organs are to 

 be found, without doubt, in a host of plants of this class ; and 

 it is allowable for us to suppose that the different groups 

 present different forms. I should have been able myself to 

 add yet many genera to those which I have mentioned, but 

 I believe that it would be sufficient in this first work to in- 

 dicate the principal types which observation has, up to the 

 present time, made me acquainted with, and to cite for each 

 of them a genus in which this type is found. I would add 

 in conclusion, in order to give more authority to my asser- 

 tions, that M. Decaisne has verified the most part of my 

 results ; and that I owe him even certain of the figures which 

 accompany this note. (Ann. des Sciences Nat. 1843.) 



c 3 



