268 TRANSACTIONS OF THE SOCIETY OF 



gerine plants iu France, expressed his doubts as to their definite estab- 

 lishment, and gave some examples of exceptional and temporary devel- 

 opment of plants. 



While exhibiting to the society a flower of the orchid order, the An- 

 grwcum sesqidpedaley a plant which is a native of Madagascar and only 

 very recently introduced into Europe, M. E. Boissier gave us the views 

 of Darwin in regard to the mode of fecundation of this flower. It is re- 

 markable for a spur of extraordinary length, the elongation of which 

 Darwin considers must be the consequence of the length of the proboscis 

 of a certain butterfly which is still unknown, and which would be the 

 only insect which could determine the fecundation of this orchid. In 

 fact, iu all the flowers provided with short spurs, as this butterfly touches 

 the nectar with the end of its proboscis, and does not introduce the lat- 

 ter entirely, it does not carry off pollen with its head. Such flowers, in 

 consequence, do not participate in the fecundation of the others, and 

 tend to disappear. M. Boissier made some objections to this theory, 

 which he considers insufficiently founded upon observation and even 

 logical deduction. 



M. Miiller claimed to have proved in a striking manner the intimate 

 mingling of the two distinct forms of the ordinary cowslip or primrose, 

 and gave this fact as a remarkable example of dimorphism. He recalled 

 to mind that if fecundation takes place under the most favorable condi- 

 tions, it must be between flowers of opposite form. 



A communication was made to us by M. Lichtenstein, of Montpellier, 

 upon the ravages caused in vineyards by the Phylloxera vastatrix. In 

 the same family of plants certain species seem to be spared by this dis- 

 ease. Thus, although the European vine transported to America may 

 bo affected by it, it does not attack the vine indigenous to America. 

 M, Lichtenstein has not observed in Switzerland the injurious species of 

 Fhijlloxera. 



Lichens, and the theory of M. Schwandener, according to which they 

 have been assimilated to a combination of mushrooms and sea-weeds, 

 have been the subject of a communication from M. Miiller. It is true 

 that the anatomic structure of lichens exhibits the superposition of 

 green cells called gonides, and this is analogous to that of sea-weeds, 

 also a felty tissue containing no chlorophyl, iu which it resembles the or- 

 ganization of mushrooms ; but still we never find among the lichens the 

 effects produced by the parasitism of the mushrooms, and there exist 

 among them forms of fruit and spores never found among the mushrooms. 

 M. Miiller does not accept this theory, and sees in lichens a dimorphism 

 of which the two terms are : 1. A complete state, known under the name 

 lichen. 2. An incomplete state, never producing fruit, and which cor- 

 responds to the lichen which grows in an isolated condition. 



M. Duby informed the society that an anomalous moss had been sent 

 to him from New Caledonia. He described two characteristics found iu 

 no other known moss, which establishes a new genus. The name Mr. 



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