INTRODUCTION. . XV11 



Classes are distinguished by the stamens and pistils 

 being in separate flowers. 



Class XXI. MONCECIA, stamens and pistils in different 



flowers, but on the same plant. 

 XXII. DICECIA, stamens and pistils in different 



flowers and on separate plants. 

 XXIII. POLYGAMIA, flowers of three kinds ; some 

 having stamens only, some pistils only, 

 and some both stamens and pistils. 

 XXIY. CRYPTOGAMIA, flowerless plants, or those 

 in which stamens and pistils have not 

 been detected, fructification being per- 

 formed by other organs. 



Each of the Classes is subdivided into two or more 

 ORDERS. The ORDERS of the first Thirteen Classes depend 

 on the number of the Pistils. Thus, any plant in either 

 of the Classes from MONANDRIA to POLYANDRIA must be 

 placed in one or other of the following ORDERS : 

 Order MONOGYNIA, one pistil. 

 DIGYNIA, two pistils. 

 TRIGYNIA, three ditto 

 TETRAGYNIA, four ditto. 

 PENTAGYNIA, five ditto. 

 HEXAGYNIA, six ditto. 

 HEPTAGYNIA, seven ditto. 

 DECAGYNIA, ten ditto. 

 DODECAGYNIA, twelve ditto. 

 POLYGYNIA, many ditto. 



In the Fourteenth Class, DIDYNAMIA, there are two 

 Orders. 



Order I. GYMNOSPERMIA, ovaries four, one-seeded. 



II. ANGIOSPERMIA, ovary single, many-seeded. 

 In the Fifteenth Class, TETRADYNAMIA, there are two 

 Orders. 



Order I. SILICULOSA, fruit a silicle, or short pod with- 

 out a partition. 



II. SILIQUOSA, fruit a silique, or long pod with- 

 out a partition. 



