122 JOUENAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Similarly in a Columbine every one of the five petals has a spur which 

 secretes and holds the honey, and this flower can be approached from all 

 sides ; but when we compare it with the Deadnettle (fig. 50), Salvia (fig. 

 51), or Aconite we find that the bees only visit these flowers from one 

 side, i.e. in front, as they all have very short pedicels, and are arranged 



Fig. 50. — Vertical section of Hower of Fig. 51. — Flower of Salvia, visited by 



Deadnettle. a humble-bee. 



f 



close to the main axis or stem. TJiis is the rule for all irregular floicers. 

 Hence we see an obvious ..coincidence between "irregularity " and a 

 special method of visiting flowers. 



But it is when we come to study such flowers in detail that we discover 

 innumerable structures w.hich, taken together, supply an irresistible 

 amount of inductive evidence in support of the theoretical contention 

 that they have all been evolved simultaneously in response to the direct 

 and mechanical actions of the insects visiting the flowers. 



Let us take the family called " Labiates " and the Deadnettle (fig. 50) 



Fig. 52. — Flower of Salvia, showing Fig. 53. — Flower of Salvia, reverting 



action of anthers. to regularity. 



as a type. The first thing the insect requires when coming to it from the 

 . front is something to alight upon. The front petal has therefore grown 

 out much larger than all the rest and forms the "lip." Now the weight 

 of the bee has to be supported, the basal parts of the petals cohere into a 

 tube accordingly ; and as the tube is very slender compared "wdth the 



