Polygonum Amphibium. 45 



tiful rosy flowers of this plant are collected in small 

 cymes, and these form a thick cylindrical rich spike- 

 shaped inflorescence, 2-5 to 3-5 cm. in length, and 1 

 to 1-2 cm. in width. The segments of the perianth 

 are free almost to the base. The ovary is surrounded 

 by a red, fleshy, five-lobed, nectar-bearing cup ; and the 

 bottom of the flower also is richly filled with nectar. 

 The stamens, which are adherent to the base of the 

 perianth, are very short, and the anthers remain hidden 

 in the interior of the flower. The two styles on the 

 contrary are very long, and project beyond the divisions 

 of the perianth. When the flower is in fuU blossom, 

 the length of the perianth is 4 mm., and its width, 

 at the upper end, scarcely 3 mm. As the nectar 

 at the bottom of the flower is not protected by any 

 special formation in the perianth, it appears to be very 

 accessible to small insects, and is in fact much sought 

 by them; but owing to the above-mentioned dimen- 

 sions of the flower, even very small insects, so long as 

 they come by flight, cannot help touching, on their 

 way to the nectar, first the stigmas, which project 

 beyond the perianth and are somewhat^ divergent, and 

 then the anthers, which are in close proximity to the 

 nectar. And as the blossoms are proterandrous, even 

 very sm^U flying insects, since they visit many flowers 

 and spikes of flowers in succession, wiU occasion inter- 

 crossing, which will sometimes be geitonogamous, 

 sometimes xenogamous. Small wingless insects, on the 



