XXxii PRELIMINAKY DISCOUKSES. 



flowering plants those organs are generally in separate flowers, 

 and are thus classified: In the 21st Linnaean Class, named Monoe- 

 cia, the stamens and pistils are in separate flowers, on the same 

 plant: In the next Class, called Dioecia, they not only occupy 

 separate flowers, but those flowers are on different plants. 



There are, however, a number of plants, in which the stamens 

 and pistils are separate in some flowers, and associated in others 

 either on the same, or on two, or even three, different plants. These 

 anomalies, LINNAEUS placed in a Class which he named Polygamia ; 

 but they have been, by later Botanists, distributed among the other 

 Classes. 



The 24th, or last, of the Linnaean Classes (now more commonly 

 numbered as the 21st), is named Cryptogamia. It comprises those 

 multitudinous vegetable forms which seem to be destitute of flowers, 

 or, at most, have only the analogues, or equivalents, of stamens 

 and pistils. The subdivisions of this Class are, of necessity, in 

 accordance with the natural system ; and the genera are therefore 

 grouped in appropriate Orders as Ferns, Mosses, Lichens, Fungi, 

 and Algae. 



The ORDERS, or secondary divisions, of all the Linnaean Classes 

 from Monandria to Polyandria, inclusive are founded on the 

 number of distinct styles, or stigmas, and are numerically arranged. 

 The Class Didynamia is divided into two Orders : one, called Gym- 

 nospermia, because it produces a thin-coated, and usually 4-lobed, 

 fruit, resembling naked seeds, or nutlets : the other, bearing mani- 

 fest seedvessels, and therefore named Angiospermia. The Class 

 Tetradynamia is likewise divided into two Orders founded on the 

 size, or rather length, of the fruit, one, called Siliculosa, having a 

 Silicle or short pod, and the other, Siliquosa, with a Silique or long 

 pod. In the remaining Classes of the flowering plants with the 

 exception of Syngenesia the Orders are established on the number, 

 or connection of the stamens. 



The Orders of the Class Syngenesia are founded on the florets, in 

 the compound heads, and are as follows : 



1. Polygamia aequalis, where the florets are all perfect. 



2. P superflua, where the central, or disk florets are perfect, 



and the ray florets are merely pistillate. 



3. P fruslranea, where the disk florets are perfect, and the ray 



florets neutral (or vacant). 



4. P necessaria, where the disk florets are staminatc, and the 



r ay florets pistillate. 



