NYLANDER ON THE ALOO-LICIIEX HYPOTHESIS, &0. 151 



would there be wanting oilier observations in regard to that divi- 

 sion of Lichens which the author admits, and upon which subject 

 he lias neglected many more recent documents. 



Jn the same place \>i\ Weddell says, in a note — " The oxalate of 

 lime constitutes . . . one of the essential characters of this 

 class of plants." This is an error, for the occurrence of oxalate of 

 lime in octohedral crystals is not to be regarded but as a character 

 in doubtful cases, distinguishing the thallusof a lower Lichen from 

 those Fungi which it resembles. But oxalate of lime is especially 

 peculiar to certain medullas (vid. Nyl. Syn., p. 11); on the other 

 hand, it is entirely absent — for example, in the Collemacei, as is 

 shown in every microscopical drawing of their thalli yet published, 

 and which is altogether elementary. Elsewhere 1 have indicated 

 (Nyl. Obs. Peziz. Fenn., p. 37), under Peziza amentacea, Balb., " The 

 hypothecium contains crystals of oxalate." 



II. 



"With respect to the Lichens of the public garden of Blossac com- 

 pared with my note concerning those of the garden of the Luxem- 

 bourg, at Paris, I may observe that my intention in it was only to 

 show what Lichens might be found in the midst of a very large 

 city,* which can in no way be compared with the vegetation 

 of a town which entirely presents the vegetation of the 

 neighbouring rural tracts. Concerning chemical re-agents, we find 

 it laid down — •' The truth is, an experience of many years 

 permits me to affirm that there are some things in the new method 

 to accept and some to reject." We may expect to learn from the 

 experience of the author, what, in his judgment, are to be rejected, 

 and what, on the contrary, are to be approved of or retained. Also 

 the incomparable writer of Upsala, thinking in former publications, 

 11 the reactions fallacious and variable," and " of little or no im- 

 portance," lately confesses and kindly concedes, that " he does not 

 entirely despise this character, sometimes as auxiliary" (that is 

 nearly sub-auxiliary) " Scand.," p. GO ; nevertheless, he expounds 

 no better character in his writings, and most eagerly adduces the 

 chemical characters indicated by me, than which none others are 

 indeed more constant. He looks down upon them, but he lays 

 hold of them.f The naked truth is (" la verite est") that the 



* Not a single Lichen, and scarcely even the trace of any thallus, are to be 

 perceived in any of the public parks of London. — J. M. C. 



t In the same place there occur these words — " It would be incongruous if 

 lichens and not also other plants could be distinguished in this way." But the 

 opinion may rather be regarded as incongruous, which would maintain that lichens 

 in this respect are of an identical nature, for they show a nature altogether pecu- 

 liar. Nor may it be overlooked that in Th. Fr. " Scand.," p. 187, there is openly 

 announced " a new discovery." The author declares that he has employed acetic 

 acid as a reagent " with great success." He may not, therefore " despise" this 

 lucky acetic acid, but happily use it. The next time he will no doubt reveal won- 

 derful things effected by the help of this acid, and what splendid successes he has 

 obtained. 



