284 BRITISH FLOWERING PLANTS chap. 



ovary contains 4 ovules, whereas the fruit contains 

 only one or two seeds. In the Privet, however, the 

 pericarp becomes fleshy, forming a berry. 



APOCYNACEiE 



Chiefly a tropical family of trees or shrubs, with a 

 milky juice, and opposite leaves. We have only one 

 genus. 



ViNCA (Periwinkle) 



Homogamous flowers, with concealed honey, secreted 

 at the base of the ovary. We have two species : Vinca 

 major, which has become naturalised in copses and 

 hedges, with broad leaves, large flowers, and a fringed 

 calyx ; and V. minor, a doubtful native, with narrower 

 leaves, smaller flowers, and the calyx quite glabrous. 



V. minor.' — The curious structure of this flower 

 (Figs. 184-186) was described independently by Darwin 

 and Delpino. The flower forms a tube 11 mm. in 

 length. The honey is secreted by two yellow nectaries 

 at the base of the ovary, and is protected from raiu 

 by a number of hairs at the opening of the corolla. 

 The stamens are attached to about the middle of the 

 tube, are bent like a knee, and the anthers, which 

 are hairy, lie over the stigma. The stigma is conical, 

 expanding upwards, and terminating in a curious flat 

 plate. The edges of this are sticky and constitute 

 the stigma, while the upper surface is hairy. The 

 pollen is shed into the space above the stigma, 

 which, however, it cannot reach on account of the 

 brush of hairs. Insects are able to force their heads 

 into the upper part of the tube, so that a proboscis 

 8 mm. long is able to reach the honey. It becomes 

 smeared by the sticky secretion, and on being with- 

 drawn some of the pollen adheres to it and consequently 

 is carried to another flower and deposited on the stigma. 



