PRELIMINARY DISCOURSES. 



complete analysis being carried through the system, from the 

 primary divisions down to the species, it is evident that the study 

 of a single plant of each group will give a correct general idea 

 of the structure, habits, and even the sensible properties, of the 

 whole." GRAY'S Text-book. 



The vegetable kingdom, viewed in reference to the natural 

 system, is divided primarily into two great SERIES, a higher one, 

 called phaenogamous or flowering plants producing proper flowers 

 (with stamens and pistils), and seeds containing a ready-formed 

 embryo or young plantlet and a lower one, called cryptogamous 

 orflowerless plants, which are reproduced by little cellular analogues 

 or equivalents of seeds, termed spores, without the agency of proper 

 flowers. 



The higher SERIES (or flowering plants) which embraces the larger 

 and more important portion of the vegetable kingdom is divided 

 into two Classes, named Exogens, and Endogens. The difference 

 between these two Classes pervades their whole port and aspect, 

 and is manifest from their earliest stage of existence. The embryo 

 of Exogens is provided with a pair of opposite cotyledons (rarely with 

 more than two as in some of the Coniferae, or Pine family), that 

 of Endogens, with only one,- whence the former have been also 

 termed Dicotyledonous, and the latter, Monocotyledonous plants. 

 There is a remarkable difference, likewise, in their foliage; the 

 leaves of the Exogens generally having reticulated or netted veins, 

 and falling off by an articulation, or separable joint, while the 

 Endogens have nearly parallel-veined leaves, which are not articu- 

 lated, but wither on the stem. 



The class of Exogens is divided into two Sub- Classes ; the one, 

 much larger, bearing their seeds in a proper Pericarp, or closed 

 Seedvessel, and hence called Angiosperms ; the other (containing a 

 couple of Orders), having the seeds naked, i. e. borne on an open 

 scale, or seated in a fleshy disk, andtherefore called Gymnosperms. 



The Subclass of Angiosperms contains so many Orders, that it 

 has been found convenient to adopt some rather artificial divisions, 

 based on the character, or absence, of the Corolla. The first 

 division comprises those exogenous plants, in which the petals of the 

 flower are all nearly or quite distinct, or separate from each other, 

 and are termed polypelalous, or more accurately, dialypetalous 

 Exogens. The second division is composed of those in which the 

 petals are more or less completely united by their margins into one 

 piece forming a sort of tubular corolla, and the plants of this 

 division have been called monopetalous, but more properly gamo- 

 petalous Exogens. 



