HIGHER PLANTS 



it. On the second day the same flower opens wide ; its anthers 

 burst with pollen and insects carry this to the stigmata of 

 other half -opened flowers. Thus cross-fertilization is brought 

 about and self-fertilization is prevented. 



Occurrence.— Common in quiet waters. Blooms May- 

 September. New York southward and westward. In the 

 northwest and northeast it is largely replaced by a variety 

 whose flowers are partly purple. 



Animal associates. — Leaf -miners eat channels through the 

 leaves and the caterpillar Nymphula cuts its waterproof 

 tents out of them (p. 258). The leaf -beetle Donacia lays its 

 eggs (Fig. 216) on spatterdock pads early in the season, and 

 on the white lily later when water has gone down leaving the 

 stiffer-stemmed spatterdocks high in the air. In winter 

 muskrats feed on the creeping rootstocks. 



Small yellow pond-lily, Nymphaea microphylla. — This spe- 

 cies is a smaller edition of the common spatterdock. It is a 

 much more slender plant with yellow flowers scarcely an 

 inch wide; the stigma is dark red. Only locally common. 

 Blooms July-August. New England to Pennsylvania and 

 Minnesota. 



Pond-lily, Castalia odorata. — Pond-lily (Fig. 76) and sweet 

 water-lily are common names for this plant which is well 

 known to everybody but especially to insects. Its familiar 

 rich green lily-pads, leathery and waterproof on the upper 

 side, often crimson beneath, can withstand hea\y rain and the 

 wear and tear of jostling by wavelets (PI. X) . The flowers are 

 pure white or pinkish with rich golden centers; the pungent 

 sweetness of a pond of blossoming lilies fills the neighborhood. 

 Stamens and pistil are in the same flower, but they mature 

 at different times and it is left for insects to transport the 

 pollen from one flower to another. The entertainment 

 offered to them is bountiful but brief; the flowers do not 

 open until the morning sun shines on them, and they close 

 in early afternoon. During that time they are probably 



93 



