DEPOSITION OF POLLEN. 



279 



the stigma, but brushes off the pollen from the anthers. The same arrangement 

 is repeated with but little deviation in the flowers of the Asarabacca (Asarum). 

 The opening of the perianth in this flower begins with the appearance of three 

 fissures between the three perianth-lobes, and these serve as entrance-gates for the 

 small flies seeking access to the interior of the flower (see fig. 279 ^^). The stigmas 

 which are to be pollinated are close below the three fissures, and the insects using 



Mg. 279.— Arrangements for the Retention of the deposited Pollen. 



1 Flower of the Violet (Viola odorata); part of the corolla cut away. 2 Capitate end of the style of this flower seen from 

 underneath. » Pistil of the Violet surrounded hy the cone of anthers; pollen Is deposited on the small lip of the capitate 

 stigma by the proboscis passing in the direction of the arrow. * Stigma of the Narcissus (Narcissus poeticus) with finely 

 toothed margin. 6 Stigma of Gladiolus (Gladiolus segetum) with ciliated edges. ^ PistU of Sarracenia purpurea ; the 

 ovary surrounded by the stamens. ? Funnel-shaped stigma of the Crocus (Crocus sativus) ; one of the three stigmas only 

 remaining, e Flower of the Mandrake (Mandragora v&malis) in the first stage of blossoming. 9 The same in the later 

 stage of blossoming. Part of the corolla and calyx cut away. 10 Flower of the Sundew (Drosera longifoUa) seen from 

 above. " Part of the sticky papillose stigma of the Sundew. 12 Flower of the Asarabacca (Asarum JSuropoBum) in the 

 first stage of blossoming. 18 The same fiower at a later stage. 1* Stigma of Roemeria. 16 stigma of Opuntia nana. 

 1* Stigma of Thunbergia grandijlora ; pollen is deposited on the lower lip by a proboscis passing in the direction of the 

 arrow. i7 Flower of Azalea procurnbens ; portions of the calyx and corolla cut away, is Pistil of the Opium Poppy 

 (Papaver somniferum). « and is natural size ; the others somewhat enlarged. 



them as entrance-gates must of necessity pass over the stigmas. If they come 

 laden with pollen from an older flower they cannot avoid leaving a portion behind 

 on the stigmas. Later, when the stigmas are polKnated, the three perianth-lobes 

 separate at the tips also, where they have hitherto been joined together (see 

 fig. 279 ^'). It is then no longer necessary that the insects should be shown the 

 way to the stigmas. 



No less important than the position of the stigma and its relation to the rest of 



