Yellow and Orange 



in. " To show how closely the edge fits," says Charles Darwin, 

 " I may mention that my son found a daphnia which had inserted 

 one of its antennae into the slit, and it was thus held fast during a 

 whole day. On three or four occasions I have seen long narrow 

 larvae, both dead and aiive, wedged between the corner of the valve 

 and collar, with half their bodies within the bladder and half out." 

 Professor Cohn of Germany tells of immersing a plant of this 

 bladderwort one evening in clear water swarming with tiny crus- 

 taceans, and by the next morning most of the bladders contained 

 them, entrapped and swimming around in their prisons. 



So much for what is going on below the surface of the water: 

 what above it? Several. flowers on the showy spike attract nu- 

 merous insects. One alighting on the lower lip must thrust his 

 tongue beneath the upper one to reach the nectar in the spur, 

 passing on its way the irritable stigma, which receives any pollen 

 he has brought in. Instantly it is touched, the stigma folds up to 

 be out of the way of the tongue when it is withdrawn from the 

 spur now laden with fresh pollen. It is thus that self-fertilization 

 is escaped. Many vigorous seeds follow in each capsule. This 

 marvellous piece of mechanism is what Thoreau termed " a dirty- 

 conditioned flower, like a sluttish woman with a gaudy yellow 

 bonnet" ! 



Not through its seeds alone, however, has the little plant 

 succeeded in firmly establishing itself. In early autumn the stems 

 terminate in large buds which, falling off, lie dormant all winter 

 at the bottom of the pond. In spring they root and put forth 

 leaves bearing bladders, which at this stage of existence are filled 

 with water to help anchor the plant. As flowering season ap- 

 proaches, the bladders undergo an internal change to fit them for 

 a change of function ; they now fill with air, when the buoyed 

 plant rises toward the surface to send up its flowering scape, while 

 the bladders proceed with their nefarious practices to nourish it 

 more abundantly while its system is heavily taxed. 



The Horned Bladderwort (U. cornuta), found in sandy 

 swamps, along the borders of ponds, marshy lake-margins, and in 

 bogs from Newfoundland to Florida, westward to Minnesota and 

 Texas, bears from one to six deliciously fragrant yellow flowers 

 on its leafless scape from June to August. It is "perhaps the most 

 fragrant flower we have," says John Burroughs. "In a warm 

 moist atmosphere its odor is almost too strong. ... Its 

 perfume is sweet and spicy in an eminent degree." The low 

 scape, rooting in the mud, has some rootlike stems and branches, 

 sometimes with a few entire leaves and bladders. Its benefactors, 

 bumblebees and butterflies, with their highly developed aesthetic 

 taste, are attracted from afar by this pleasing flower, whose acute, 

 curved spur filled with nectar may not be drained by small fry, to 

 whom the hairy throat is an additional discouragement. 



336 



