14.0 



THE STRUCTURE OF FLOWERS. 



CHAPTER XVI. 



SECRETIVE TISSUES. 



Position of Nectaries.* — These honey-secreting organs 

 seem capable of being formed anywhere. Of course they 

 are mainly to be found in flowers, but many plants bear 

 them elsewhere. Thus, some ferns have them on the rachis ; 

 the common laurel, as also the almond and peach, have two 

 at the base of the petiole ; beans and vefches, as well as 

 species of Imjoatiens, have them on the stipules, as shown in 

 Fig. 43. Bees may be often seen as busy about the young- 

 shoots of laurel as 

 if they were visiting 

 flowers. Acacia 

 s;ph(Brocei)liala has a 

 large one, on the 

 upper side of the 

 petiole, which sup- 

 plies those ants with 

 food which take up their abode in the gigantic stipules 

 peculiar to that genus. f 



* Les Nectaires, Ann. des Sci. Nat., Bot., vol. iii., p. 1, 1879 ; also, 

 Etudes Anatomiques et Physiologiques des Nectaires, Compt. rend., torn. 

 Ixxxviii., p. 662, 1879; also, Cross and Self Fertilisation of Plants, -p. 402; 

 also, Stadler, Beitr. z. Kenntniss d. "Nectarieen ii. Biologie d. Blilthen. 



t See Belt's Naturalist in Nicaragua ; also a paper by F. Darwin, 

 in Trans. Lin. Soc, on the same subject. 



Fig. 43. — stipules of Impatiens : a. section showing anatomy 

 b, with a drop of honey in the centre (after Kerner). 



