TO BOTANY. 83 



CHAP. XX. 



OF THE SEVENTEENTH CLASS DlADELPHIA *. 



THIS Class consists of such plants as bear her- 

 maphrodite flowers, furnished with ttvo sets of united 

 staminaf. The characters of the fructification are 

 as follow : 



Characters of the Class DIADELPHIA. 



CALYX. A perianthium monophyllous, campa- 

 nulate, and withering. The base gibbous, the lower 

 part thereof fastened to the peduncle, the upper 

 obtuse and melliferous. The brim quinquedentate, 

 acute, erect, oblique, unequal. The lowest odd 

 denticle lower than the rest; the upper pair shorter 



* The plants of the class Diadelphia are the Papilionaceous, 

 butterfly-shaped plants, of Tournefort ; irregular Tetrapetal- 

 ous, of Rivinus; and Leguminous of Ray, Hist. Plant. 883. 

 Of all the classes this is the most natural, and has its flowers 

 of the most singular structure. The calyx, though hitherto 

 little attended to, is of great moment for fixing the genera. 

 The icgumen was held of consequence by other Systematists, 

 but by Linnaeus it is made of less account. The leaves of 

 these plants are food for cattle, and the seeds also for quad- 

 rupeds of the same kind ; the latter are accounted flatulent. 



f This circumstance implied in the title does not hold 

 through the class, the plants given under the first distinction 

 of the third order having monadelphious stamina ; the class is 

 therefore not so properly to be fixed from its title, as by the 

 papilionaceous corolla, and other characters of the fructifica- 

 tion. It may be observed likewise, that in the diadelphious 

 flowers of this class, one of the two stamina is not a set of 

 united filaments as in the other, but only a single stamen de- 

 Uched from the united set. See the characters of the fruc P 

 tiiication. 



