CALYCIFLOR^ 197 



the soil by the plant itself. The latter also con- 

 sumes the bacteroids; hence the value of leguminous 

 plants for a rotation of crops and as manure when 

 ploughed in. 



The British Papilionaceae include herbs and some 

 shrubs. The leaves are alternate, trifoliate, or simple, 

 with stipules, and the leaflets have stipulae. 



The inflorescence is a raceme, or variety of that, a 

 panicle or spike. The flowers are irregular. The 

 calyx consists of five sepals united below, sometimes 

 two-lipped, as in the Trefoils. There are five unequal 

 petals, which are distinct or adherent by the claw to 

 the staminal tube. The upper standard is broad 

 outside in bud. The two wings are lateral, interior 

 in bud, enclosing or adhering to the two lower petals. 

 These form the keel, interior in bud, and distinct or 

 united by the lower edge. There are ten stamens 

 which unite to form a tube, or the upper tenth one 

 may be separate. They are equal, or the alternate 

 ones are longer. The ovary is one-celled. The style 

 is bent inwards. 



The stigma is oblique or terminal. The fruit is a 

 dry pod or legume, opening along both sutures, or 

 not. The seeds have a leathery coat. 



The flowers are proterandrous, and they exhibit 

 great variety and complexity of mechanism, such as 

 the piston apparatus, and are explosive, with trigger 

 arrangements. 



The fruit walls frequently contract when dry, and 

 the seeds are scattered to a distance. 



