170 



on one hand with his conceptions about the necessity of 

 cross-fertilisation for the maintenance of the vital energy 

 of the species, on the other hand with the theory of 

 natiiral sélection, the investigation of still another signi- 

 ficance of the nectaries for the plant was for a long period 

 entirely abandoned. 



Not until 1878 this subject was again broached by 

 B n n i e r ') who, in his extensive paper on the nectaries, 

 in which as well the anatomical as the physiological side 

 of the problem were submitted to a very extensive investi- 

 gation, proved that sugar-containing tissues in the flower 

 and especially in the inmediate vicinity of the ovary are 

 not only found with plants which regulary secrète nectar 

 during the flowering, but also with such plants as under 

 normal conditions never secrète such a liquid. With thèse 

 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 

 „insects flowers". Even with anemophilous plants he found 

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

 sativum and Hordeum muriniim. A numberof plants which 

 under ordinary conditions of life contain no nectar, he 

 could induce to neçtar-secretion by placing them under 

 conditions favourable for this purpose. 



At the end of his paper he reminds us that an accumu- 

 lation of reserve materials, wherever a temporary stagna- 

 tion in the development exists, may be considered a very 

 gênerai and well characterised phenomenon. When a plant 

 stops its further development at the end of its growing 

 period, it bas stored up reserve material in its subterra- 

 nean parts and when the seed has finished its develop- 

 ment, it has accumulated nourishing substances in the 



1) Gaston Bon nier. Les nectaires. Étude critique, anatomique 

 et physiologique. Annales des sciences naturelles. Tome VIII. 1878. 



