DEPOSITION OF POLLEN. 



279 



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

 is repeated with but little deviation in the flowers of the Asarabaeca (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 



Fig. 279.— Arrangements for the -Retention of tlie deposited Pollen. 



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

 underneath. « Pistil of the Violet surrounded by 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 poeticxts) with finely 

 toothed margin. * Stigma of Gladiolus (Gladiolus segetum) with ciliated edges. « Pistil of Sarracenia purpurea ; the 

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

 remaining. 8 Flower of the Mandrake (Mandragora vernalis) 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 longifolia) seen from 

 above, n Part of the sticky papillose stigma of the Sundew. 12 Flower of the Asarabaeca (Asarum Europmum) in the 

 first stage of blossoming, 's The same flower at a later stage. " Stigma of Roemeria. i^ stigma of Opuntia nana. 

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

 arrow, w Flower of Azalea procumbens; portions of the calyx and corolla cut away. 18 Pistil of the Opium Poppy 

 (Papaver scminiferum). 6 and 18 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 pollinated, 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 



