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TRANSLATIONS. 



On the Impregnation and Germination of A'lgm. By M. 

 Pringsheim. (Abridged from the Reports of the Berlin 

 Academy.) 



The existence of sexuality in the vegetable kingdom, though at 

 first surmised simply upon a presumed analogy in this respect 

 between animals and plants, and long a disputed point in 

 science, has for some time been admitted as an indisputable 

 fact. In the Phanerogamia especially, the necessity of the 

 conjunction of the pollen tube and the ovule for the produc- 

 tion of the embryo can no longer be denied by any one. 

 Observations and experiments whose results admit of no dis- 

 pute, have established this fact, although opinions may vary 

 as to the essential nature of the act of impregnation. 



The sexual organs of the higher Cryptogamia also are 

 known ; but with respect to the mode in which the respective 

 organs participate materially in the act of impregnation, and 

 even as regards the necessity of their co-operation, we possess 

 at present little more than vague surmises. 



In the FloridecB^ Fucoidece, Lichens, and Fungi, older and 

 more recent researches have, at most, merely indicated the 

 existence of organs to which sexual functions may possibly 

 be assigned. 



The latest endeavours, lastly, to demonstrate the existence of 

 antheridia in the fresh-water Algce, with the exception of 

 certain fortunate indications, to which I shall return, may be 

 said to have wholly failed. 



This condition, however, of our knowledge, with respect to 

 the sexuality of plants, cannot be regarded as very encou- 

 raging. For, admitting that, in order to prove the existence 

 of sexuality it is not sufficient to show the presence of dif- 

 ferent organs, to which sexual functions may by possibility 

 belong, but also to demonstrate the co-operation of these 

 organs in the formation of the seed or of the young plant ; it 

 is obvious that the sexuality of plants, even in that division 

 of the vegetable kingdom in which the organs to which the 

 sexual function has been assigned are already known, has 

 not been demonstrated with that degree of certainty which 

 admits of no doubts being entertained. The grounds upon 

 which the existence of sexual relations in the Cryptogamia, 

 has been assumed, properly reside only in the analogy between 



