PEA FAMILY 



485 



unite (Fig. 432). In the uniting of some of the petals, the plants 

 of the Pea family suggest those of the Sympetalae which is 

 considered the most advanced group of Dicotyledons. Also 

 irregularity in the shape or size of sepals or petals is considered 

 an advanced feature. The pistil consists of one carpel and be- 

 comes the one-celled fruit called legume, which is characteristic 

 of the family. 



The Beans, Peas, Peanuts, Soy Beans, Cow-peas, Clovers, 

 Alfalfas, and Vetches make this 

 family a noted one. The value 

 of Beans, Peanuts, and Peas as 

 food for man, and of the others 

 mentioned for forage and the 

 improvement of the soil are well 

 known to the student. The Pea- 

 nut is peculiar in that it forces 

 its pods underground to ripen. 

 Although Peanuts are not so 

 important for food as Beans and 

 Peas, several millions of bushels 

 of them are grown in the United 

 States per year. From some 

 of the leguminous plants medici- 

 nal substances, dyestuffs, gum 

 arabic, licorice, logwood, copal 

 varnish, and other useful sub- 

 stances are obtained. Some of 

 the leguminous trees, as the 

 Black Locust, Honey Locust, 

 and a number of trees in the 

 tropics and sub-tropics, furnish 

 fine cabinet woods. 



Thirty or more leguminous plants are classed as weeds. 

 Some, like the Loco-weeds and some of the Lupines, are poison- 

 ous to live stock and cause considerable trouble in pastures in 

 the Western states. Some, like the Rabbit-foot Clover, are very 

 hairy and when eaten by stock, the hairs often collect in balls 

 and clog the intestines. In the Tick Trefoils, of which there are 

 many species, the fruits are commonly spiny and are trouble- 

 some to wool-growers. 



FIG. 432. Flowers and fruit of 

 the Common Locust (Robinia 

 Pseudo- Acacia). At the right, a 

 raceme of flowers, showing the 

 irregular corollas ( X ) ; at the left, 

 above, a flower with a portion of 

 corolla removed to show the diadel- 

 phous stamens; at the left, below, 

 a mature pod or legume 

 After Burns and Otis. 



