( 394 ) 



With Fritillaria imperialis I found the same ; but here the secretion 

 of nectar was not so abundant as in buds, the anthers of which had 

 not been removed. In my opinion these observations indicate that 

 the sugar, stored up in the nectaries or other sugar-containing tissues 

 of the flower, a( the moment when it begins to exert its osmotic 

 action, attracts water not only from the anthers but also from other 

 parts of its surroundings. 



3. With the following plants the anthers remain closed in a space, 

 saturated with water-vapour. In so far as they possess nectaries, 

 these latter appeared to exert no influence on the bursting of the 

 anthers. 



Ranunculus acris L., R. hulbosus L., Aquilegia vulgaris L., 

 Clematis Vitalba L., Chelidonium majus L., Brassica oleracea L., 

 Geranium molle L., G. Robertianum L., G. macrorhizum L., Geum 

 urbanum L., Rubus caesius L., Philadelphus coronarius L., Heracleum 

 Sphondylium L., H. lanatum Michx, Aegopodium Podagraria Spr., 

 Carum Ca7'vi L., Fimjnnella magna L., Valeriana officinalis L., 

 Ligustrum vulgare L. Majantliemum bifolium Dc, and Iris Pseuda- 

 corus L. 



It is remarkable that Brassica oleracea L. forms an exception to 

 what is otherwise generally observed with the Cruciferae; the position 

 of the stamens with respect to the nectaries which secrete honey 

 abundantly, would make us expect that in a moist chamber they 

 would behave like the others. The same remark holds for the species 

 of Geranium. 



The secretion of nectar in the flower attracted the attention of 

 various investigators many years before Spkengel published his view 

 of the matter. Also after Sprengel, in the flrst iialf of the preceding 

 century, it has many times been the object of investigation. All these 

 investigators agreed in being convinced that, apart from the signi- 

 ficance of the honey-secretion for the fertilisation of the flowers by 

 the intervention of insects, to which Sprengel had drawn attention, 

 the sugar-containing tissues and the secreted liquid were still in 

 another respect useful to the plant. 



After Darwin had in 1859 brought to the front again Sprengel's 

 observations on the biological significance of the various properties 

 of the flower — which observations were falling more and more 

 into oblivion — and had accepted their consequences by bringing 

 them into relation on one hand with his conceptions about the 

 necessity of cross-fertilisation for the maintenance of the vital energy 



