THE PIGWORT FAMILY. 245 



This plant has been widely introduced into the United 

 States, and, notwithstanding its botanical interest, is a 

 pernicious weed, difficult to eradicate. Aside from repro- 

 duction by seed, it persistently maintains itself by means 

 of its rhizomes, each ol which sends up several or many 

 aerial shoots. The unpleasant odor and taste of the 

 plant render it distasteful to grazing animals, so that 

 it is efficiently protected by its own disagreeable prop- 

 erties. 



The adaptations for securing cross-fertilization by the 

 agency of insects are striking, and, for the most part, 

 easily understood. The flowers are rendered conspicuous 

 by massing in a crowded raceme, and face outward, so as 

 to be immediately accessible to flying insects, while the 

 orange-colored palate, with its smooth median groove on 

 the inner side, directs visitors at once to the nectar col- 

 lected in the spur. The anthers and stigma are so dis- 

 posed as to come in contact with the head and back of 

 the insect (commonly a bee), as it depresses the palate 

 and inserts its long proboscis into the spur. While thus 

 accessible to large insects with a long proboscis, the nectar 

 is protected from unbidden guests by the palate, that com- 

 pletely closes the throat of the flower, and springs back 

 to its place when the force by which it is depressed ceases 

 to act. It is further protected by its position, being out 

 of the reach of insects with a short proboscis that may 

 in some way have effected an entrance into the flower. 



The mechanical arrangements for the dissemination of 

 the seeds are also of interest. The hygroscopic action of 

 the capsules is readily shown by placing them when dry 

 in vs^ater. In less than a minute the teeth at the apex 

 begin to bend inwards, and in a short time the capsule is 

 tightly closed, opening again when it has been thoroughly 



