Minnesota Plant Life. 



383 



Cow-wheats. The cow-wheats, louseworts, yellow-rattles and 

 eyebrights are remarkable for their partial parasitism upon 

 neighboring plants. If a turf containing one of these varieties 

 is dug up and the earth very carefully removed by washing, it 

 will be found that the rootlets of the figwort attach themselves 

 to those of neighboring plants and in this way extract food 

 material from the bodies of their hosts. Such plants are called 

 root-parasites. The dependent habit of these root-parasites 

 is not, however, so thoroughly fixed that they derive the 

 principal part of their nutriment in such an irregular manner 



They are all of them green 

 plants with well developed 

 leaves. The flowers are two- 

 lipped, have strongly con- 

 vex upper lips, and are of 

 various colors white in the 

 cow-wheat, yellow in the 

 rattlebox, cream colored in 

 the louseworts, and lilac or 

 purplish in the eyebright. 



Catalpa trees. One tree 

 related to the figworts, and 

 belonging to the bignonia 

 family, is cultivated in Min- 

 nesota, especially in the 

 southern part of the state. 

 This is the catalpa, a very 



FIG. 184. Bladderwort. After Britton and Brown, beautiful trCC with large 



leaves shaped somewhat like those of the linden and handsome 

 purple-mottled, bell-shaped, two-lipped flowers, produced in 

 loose clusters. The pods when full-grown are a foot or more in 

 length, cylindrical and slender. In every pod a large number 

 of winged seeds are matured and the wings stand out on each 

 side of the seed like the wings of a bird. Catalpa seeds have 

 their center of gravity very nicely balanced between the wings, 

 so that they lie flat in the air, and if there is a current of wind 

 they soar in circles like hawks, and are often carried to great 

 distances. 



