180 STUDY OF COMMON PLANTS. 



The Leguminosae constitute a large and remarkable 

 family of plants, including between six and seven thou- 

 sand species, distributed throughout the world, but most 

 abundant in tropical regions. Many of the species are of 

 economical interest. The various kinds of clover furnish 

 important forage crops, and peas, beans, and lentils form an 

 almost indispensable constituent of the food plants of the 

 world. Dye woods and drugs are yielded by a consider- 

 able number. Some are exceedingly poisonous, among 

 them the famoiis ordeal bean of Calabar. Botanically they 

 are of special interest for the peculiarities of the mechanism 

 by which their flowers are adapted to cross-fertilization. 

 A large proportion, too, of plants whose leaves exhibit 

 " sleep movements " belong to this family. 



SPECIAL STUDIES. 



I. Arrangements for cross-fertilization in the Legu- 



minosse. 



II. Extent to which the production of seeds of red 

 clover is dependent on the agency of insects. 



III. Capacity of the common pea for self-fertilization. 



IV. Occurrence of modified leaves, such as tendrils, 



phyllodes, etc., among the Leguminosse. 

 V. Morphology of protective structures of various legu- 

 minous plants, e.g. spines of locust and honey 

 locust, prickles of Schrankia, and hairs of Des- 

 modium. 

 VI. Sleep movements of clover, lupine, and other plants 



of this family. 



VII. Affinities of the Leguminosse. 

 VIII. Causes of the wide distribution of this family. 

 IX. Varieties of cultivated peas and beans. 



