11 CONVOLVULACEJi: 291 



C. arvensis (Bindweed). — The leaves are ovate- 

 sagittate ; the flowers are sweetly scented, and open 

 from about 7 A. m. to 10 p.m., closing at night and in 

 bad weather. Honey is secreted by the base of the 

 ovary, and the swollen bases of the five stamens (which 

 are adnate to the corolla) leave only five narrow entrances 

 to it. The filaments are woven together by short stiff" 

 projections at their edges, so that an insect cannot 

 insert its proboscis between them. The anthers open 

 outwards, and the stigmas project beyond them, and 

 must therefore be first touched by any visiting insect. 

 The flowers, as in so many cases, present numerous 

 diff'erences. In Belgium, MacLeod found four forms : 

 (1) that above described; (2) one with larger flowers, 

 the corolla surrounded by a red band; (3) a form with 

 small flowers ; (4) a female form, with shortened 

 stamens and rudimentary anthers. After flowering 

 the ovary curves downwards and thus protects itself 

 The flowers are often infested by a spider, Thomisus 

 onustus, which seizes the unsuspecting insects which 

 come for the honey. The plant is sometimes glabrous, 

 sometimes hairy. 



0. Soldanella. — The general arrangement of the flower 

 agrees with that of C. arvensis. The relative lengths 

 of the stamens and pistil vary considerably. Besides 

 the complete plants, MacLeod found at Blankenberge 

 some that were gynodioecious. It is a plant of sandy 

 sea-shores ; its slender root-stock helping to bind the sand. 



C. sepium. — This species has no scent, but in other 

 respects the arrangement of the flower is much the same 

 as in C. arvensis. On moonlight nights, however, it 

 remains Open. Though sometimes visited by other 

 insects, it is especially adapted to the Convolvulus 

 hawkmoth, and seldom sets its seeds where that insect 

 does not occur. The ovary does not curve downwards 

 after the flowering — perhaps, as Dutrochet long ago 

 suggested,'' because it is sufficiently protected by the 

 large bracts. The plant is glabrous. 



^ Rechenhes Anaiomiques, etc. 



