( 395 ) 



of the species, on the other hand witli the theory of natural selection, 

 the investigation of still another significance of the nectaries for the 

 plant was for a long period entirely abandoned. 



Not until 1878 this subject was again broached by Bonnier ^) who, 

 in his extensive })aper on the nectaries, in which as well the ana- 

 tomical as the physiological side of the problem were submitted to 

 a very extensive in\'estigation, proved that sugar-containing tissues 

 in the flower and especially in the immediate vicinity of the ovary 

 are not only found with plants which regularly secrete nectar during 

 the flowering, but also Avith such plants as under normal conditions 

 never secrete such a liquid. With these plants, which in the literature 

 on flower biology are called "pollen flowers", since the insects find 

 no nectar in them, he found as well sugar-containing tissues as in 

 the so-called "insect flowers". Even with anemophilous plants he 

 found "nectaires sans nectar", e. g. with Avena sativa, Triticum 

 satlvuiii and Hordeum murinum. A number of plants which under 

 ordinary conditions of life contain no nectar, he could induce to 

 nectar-secretion by placing them under conditions, favourable for 

 this purpose. 



At the end of his paper he reminds us that an accumnlation of 

 reserve materials. Avherever a temporary stagnation in the develop- 

 ment exists, may be considered a A'ery general and well characterised 

 phenomenon. When a plant stops its further development at the end 

 of its growing period, it has stored up reserve material in its sub- 

 terranean, parts and when the seed has finished its development, it 

 has accumulated nourishing substances in the endosperm or in the 

 cotyledons of the embryo. These reserxe materials, turned into assi- 

 milable compounds, theji serve for the first nutrition of the newly 

 formed parts. 



He then arrives at the conclusion that in the vicinity of the ovary 

 saccharose is stored up, and that this reserve substance after fertili- 

 sation and in the same proportion as the fruit develops, passes partly 

 or entirely into the tissue of the fruit and into the seed, after having 

 first been changed, under the influence of a soluble ferment, into 

 assimilable compounds. 



Investigation showed me also that the accumulation of saccharose 

 as a reserve substance in the fiower is a very common phenomenon '). 



1) Gaston Bonnier. Le.s neclaires. Etude critique, anatomique et physiologique. 

 Annales des sciences naturelles. Tome VIII. 1878. 



-) On this point see also : Paul Knuth, Über den Nachweis von Nektarien auf 

 chemischern Wege. Bot. Centralbl. bXXVI. Band, 1898, p. 76 and Rob. Stager, 

 chemischer Nachweis von Nektarien bei Follenbluraen und Anemophilen. Beihefte 

 zum Bot. Centralbl. Band XII. 1901, p. 34. 



26 



Proceedings Royal Acad. Amsterdam. Vol. IX. 



