32 PLANT LTFE. 



become joined, the advantage of this union or cohesion 

 is very obvious. In Lychnis the sepals are necessarily 

 joined, a most unusual character in this order, to sup- 

 port the large petals ; if the calyx is cut away the 

 petals at once fall down, being unable to support their 

 own weight. In all such flowers as the Gentian, Prim- 

 roses, etc., the union of the petals rs necessary for three 

 reasons; namely, to hold the flower erect, to form a long 

 tube for the bumble-bee, etc., and to prevent honey- 

 stealers entering in. In the Hollyhock, insects alight on 

 the bush of stamens, and obviously here union is strength. 

 As regards the ovary, it is so much more economical 

 to have the carpels joined that there are very few 

 natural orders in which the carpels remain separate. 

 (5) In many flowers the ovary is inferior^ that is, the 

 sepals, petals and stamens have become joined to it so 

 that they appear to be attached at the top of the ovary. 

 This adhesion is certainly economical, for no special 

 strengthening material is required for the separate 

 sepals, petals, etc. It is the general rule for the stamens 

 to be attached or adhere to the petals in long-tubed 

 flowers, (it is obvious that the expense of special stalks 

 is thus avoided) ; but in such cases as the Bell-heather, 

 where they are quite free, it is clearly necessary that 

 they should be so, for the insect is intended to 

 shake the anthers and bring the pollen out of the 

 holes or pores at the tip of the anther. (6) The 

 original arrangement of the flower-leaves (sepals, etc.) 

 was no doubt like that of the ordinary green leaves, 

 namely, in a spiral on the stem ; the fact that in all 

 except a very few cases they are arranged in circles may 

 be explained from the economy and better protection 

 which is obtained by their fitting together without 

 interspaces. The original method remains in the 



