THE DICOTYLEDONES 1729 



the five outer stamens bend inwards and dehisce while the five inner 

 ones are still unripe and are curved outwards. The stigmas are also 

 immature. Before the five outer stamens have withered the five inner 

 dehisce but still remain directed outwards. As the stamens wither the 

 styles elongate and the stigmas unfold above the stamens. 



All but very small insects when trying to reach the nectar must become 

 dusted with pollen in the younger flowers, whether they alight in the middle 

 or at the edge. In older flowers they are bound to come into contact with 

 the stigmas and thus efl'ect pollination. 



Failing cross-pollination the stigmatic surfaces bend back further until 

 they come into contact with the anthers, to which some pollen remains 

 adherent and thus self-pollination is ensured. This flower is normally 

 pollinated by flies, small bees and beetles. In the Alps, where the Lepi- 

 doptera abound, it is sometimes visited by butterflies. 



To the Diantheae belong all the more conspicuous members, many of 

 which are cultivated in gardens. The flowers are pentamerous with two 

 whorls of stamens. The styles are free and indicate the number of carpels 

 involved in the gynoecium. These are five in Lychnis, three in Silene and 

 two in Dianthiis and Saponaria. The ovary is sometimes chambered at the 

 base by septa which represent the lateral walls of the carpels. 



Pollination (Fig. 1605) in this sub-family is efl^ected by long-tongued 

 insects, such as the larger bees, butterflies and moths. The nectar is con- 

 cealed at the base of the deep tube formed by the sepals. We will take as 



Fig. 1605. — MelandiiiDii a/hiiiii. A, Male flower. B. Female flower. The deep calyx and 

 the lonp claws of the petals form a floral tube which simulates the conditions in a 

 sympetalous flower. (After James and Claphant.) 



