140 



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 i-achis ; 

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

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

 species of Impatiens, 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 

 sphcerocephala 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 Soi. Nat., Bot., vol. iii., p. 1, 1879 ; also, 

 Etudes Anatomiques et Physiologiqvss des Nectaires, Coinpt. rend., torn. 

 IszXTiii., p. 662, 1879 ; also. Cross and Self Fertilination of Plants, p. 402 ; 

 also, Stadler, Beitr. z. Kenntniss d. Nectarieen u, Biologie d. Bliithen. 



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 /mpotiens ; o. sertlon sbowing anatomy 

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



