CH. VI, 5] METHODS OF CROSS-POLLINATION 



293 



Not only does the structure of the typical showy flower 

 exhibit remarkable fitness to cross-pollination by insects, 

 but this fitness is carried to degrees which have evoked the 

 wonder and admiration of long generations of loving ob- 

 servers of plants. The simplest condition is found in regular 

 flowers like Buttercups or Apple blossoms,, where almost 

 any kind of insect may equally well alight in the shallow 

 basin, and, busily seeking the 

 nectar, effect pollination. This 

 is likewise the case with the 

 .Composite, the Dandelions and 

 Daisiesand Sunflowers, an 



sor In irregular flowers, such 

 as the Larkspur and Mints (Fig. 

 203), the arrangements are such 

 that only Bees and__lika insects 

 can reach the nectar in the elon- 

 gated sj5nrsI5S5bes^ and those 



principal insects which W F IG - 7 205 - ~ A flower of /" cca 



, . Whipplei, being pollinated by a 



VlSlt SUCh flowers. In these Pronuba moth; X i. 



flowers, as elsewhere, the me- . The insect deliberately col- 



7 lects pollen from one flower, car- 



chamcal arrangements are such ries it to the stigma of another, 



that the Visiting insect must take d there presses it securely 



down. It then lays an egg in 



a path which insures CrOSS-pol- the ovary of that flower, and its 



lination. In some Orchids, espe- 1* feeds on some of the seeds 



. ' ^ which would not develop without 



dally the Lady S Slipper (Flg.204)^ the pollination. (From Kerner, 



the insect has to enter the flower after work by Trelease -> 



by one opening which the stigma guards, and leave by another 

 over which hangs an anther. In Orchids, indeed T the fitting 

 of floral form to insect shape and habit has become 



fully exact, so that in some cases only a single species of 

 insect can pollinate the flower, the adjustment between the 

 two being carried remarkably into details. These, how- 

 ever, are but few of the great variety of arrangements pre- 

 sented in this relation between flowers and insects, which 

 include even a case of deliberate and purposeful pollination 



