ACROGENS. ■ - i.i> 



Endogens, 



1. Growing by internal accretions (197). 



2. Leaves parallel-veined (229) and decaying without falling off. 



3. Seeds with one cotyledon (126) or monocotyledotwusl ; 



349. Classes. The groups above mentioned, comprising the 

 whole vegetable kingdom, are again subdivided into six classes. 

 The first two are formed from the subdivision Exogens, and are 

 founded upon the presence or absence of the pericarp ; namely, 



Class L. Angiosperms, (as the oak, rose,) 



1. Ovules produced within an ovary, and 



2. Fertilized by the action of the pollen through the stigma. 



3. Becoming seeds enclosed in a pericarp. 



4. Embryo with two opposite cotyledons. 

 Class n. Gymnosperms, (as the pine, yew,) 



1. Ovules produced naked beneath a scale-like carpel. 



2. Fertilized by the direct action of the pollen without the stigma. 



3. Becoming tnily naked seeds, that is, destitute of a pericarp. 



4. Embi^o mostly with several whorled cotj'ledons. 



350. The next two classes are formed from the subdi\'ision 

 Endogens, and are founded itpon the presence and absence of 

 glumes or husks ; namely, 



Class in. Aglumace^ or aglumaceous enpogens. 



Plants of the endogenous stmcture with flowers constructed on the 

 usual plan; perianth verticillate, of one or more whorls of petaloid 

 organs, or wanting. Ex. lily, orchis, rush. 



Class IV. GLDMACEiK Or GLUMACEODS ENDOGEKS, 



Plants of the endogenous structure, die flowers invested in an imbri- 

 cated perianth of glumes instead of a calyx ; as the grasses, grains, 

 sedges. 



351. The Cryptogamia are separated into two great classes, 

 called Acrogens and Thallogensj), the former including those 

 tribes which make some approximation towards the Phsenoga- 

 mia, and the latter including the lov/est tribes of the vegetable 

 kingdom. As their names indicate, tliey are disLinguished from 

 each other by theh manner of growth ; thus. 



Class V. AcROGEXS (growing from axgo?, tlie summit or point) have a regular 

 stem, or axis, which grows by tlic extension of the point, or apex only, 

 without increasing at all in diameter, generally furnished v.ith leases, 

 and composed of cellular tissue and ducts. Ex. ferns, mosses, chtb- 

 mosscs, and the E'luisetaccye. 



