8o 



LOTUS. 



[chap. 



irregular corolla are fertilised by insects. The advan- 

 tage of the irregularity is that it compels the insects 

 to visit the nectary in one particular manner. In the 

 present group the result is that insects necessarily 

 alight on a particular part of the flower, when their 

 weight in many cases causes certain mechanical 

 effects by which the pollen is transferred to the body 

 of the insect, and thus carried from one flower to 



Fig. 66. — Loins coriiiculatits, 



another. The corolla in the Leguminosse consists of 

 five petals ; an upper one, usually called the " Stan- 

 dard," two lateral ones, or " Wings ; " and two lower 

 ones, united at their edges into a boat-shaped organ, 

 or " keel." 



The bases of the stamens coalesce into a hollow 

 tube (Fig. 70 and 71 i) the inner walls of which, at 

 their base, secrete honey in some species, though not 



