CONCKALMKNT Ol' IIONi:V 273 



different flowers. In tlic ease of tlie Yellow Gentian 

 (p. 58), wo saw that the nectary was a ring-shaped 

 swelling at the base of the ovary. In other flowers 

 certain of the stamens are modified to form honey- 

 glands, and have quite lost their original function. 

 Such cases are well seen in the Globe-flower, the 

 Hellebores, and the Monkshoods. In the Violets 

 (p. 161) and Orchids, as well as many other 

 plants, the nectary or nectaries are situated in a 

 spur. 



In some plants, such as the Yellow Gentian and 

 the Marsh Marigold, the nectar and pollen are freely 

 open to all insect visitors, which arrive on the wing, 

 though not to crawling insects. In other cases the 

 flowers are specialised for certain insects alone, such 

 as humble-bees and butterflies, which possess very 

 long probosces or tongues. This implies concealment 

 of the honey or some adaptation by which such 

 visitors can alone enter the flower. In the previous 

 chapters we have discussed several instances. In 

 some Gentians, the throat or entrance to the corolla 

 is closed, by means of scales, to all except the more 

 powerful insects, and the same adaptation is met with 

 in other plants. Again, as in members of the Pea 

 family, the flower may be so shaped that only certain 

 insects can force their way within. The honey may 

 be concealed at the end of a long corolla tube of line 

 bore, as in Daphne striata (p. 260), or in slender spurs, 

 as in Viola calcarata (p. 129), so that it can only be 

 reached by long-tongued insects. In the case of the 



