Yellow and Orange 



above the tube, drains it with none of the clown-like performances 

 exacted from the bumblebee. Pilfering ants find death as speedy 

 on the sticky surfaces here as on any catchfly. 



Greater Bladderwort; Hooded Water-Milfoil; 



Pop-weed 



(Utricularta -vulgaris) Bladderwort family 



Flowers Yellow, about ^ in. across, 3 to 20 on short pedicels in a 

 raceme at the top of a stout, naked scape 3 to 14 in. high. 

 Calyx deeply 2-lobed ; corolla 2-lipped, the upper lip erect, 

 the lower lip larger, its palate prominent, the lip slightly 3- 

 lobed, and spurred at the base ; 2 stamens ; i pistil ; the stigma 

 2-lipped. Leaves: Very finely divided into threadlike seg- 

 ments, bearing little air bladders. 



Preferred Habitat Floating free in ponds and slow streams, or 

 rooting in mud. 



Flowering Season June August. 



Distribution Throughout nearly the whole of North America, 

 Cuba, and Mexico. Europe and Asia. 



Here is an extraordinary little plant indeed, which, by its 

 amazing cleverness, now overruns the globe one of the higher 

 order of intelligence so closely akin to the animals that the gulf 

 which separates such from them seems not very wide after all. In 

 studying the water-crowfoots (p. 295) and other aquatic plants, 

 we learned why submerged leaves must be so finely cut ; but what 

 mean the little bladders tipped with bristles among the pop-weed's 

 threadlike foliage ? Formerly these were regarded as mere floats 

 a thoughtless theory, for branches without bladders might have been 

 observed floating perfectly. It is now known they are traps for 

 capturing tiny aquatic creatures : nearly every bladder you examine 

 under a microscope contains either minute crustaceans or larvae, 

 worms, or lower organisms, some perhaps still alive, but most of 

 them more or less advanced to ward putrefaction a stage hastened, 

 it is thought, by a secretion within the bladders; for the plant can- 

 not digest fresh food ; it can only absorb, through certain processes 

 within the bladder's walls, the fluid products of decay. The little in- 

 sectivorous sundew (see p>. 193), on the contrary, not only digests, 

 but afterward absorbs, animal matter. Tiny aquatic creatures, ever 

 seeking shelter from larger ones ready to devour them, enter the 

 pop-weed bladders by bending inward the free edge of the valve, 

 which, being strongly elastic, snaps shut again behind them in- 

 stantly. " Abandon hope, all ye who enter here," might be written 

 above the entrance. No victim ever escapes from that prison. 

 Scientists are not agreed that the bristles draw creatures into the 

 bladder. Whatever touches the sensitive valves is at once drawn 



335 



