)l BRITISH SEA-WEEDS. 



This Vegetable Kingdom, in analogy with its proto- 

 type, is divided, not into provinces, comities, parishes, 

 etc., but into classes, orders, genera, and species, based 

 on and in accordance with the all-wise unchanging na- 

 tural laws by which it is governed. 



The first division is into the following classes : — 



1. E.vogens, or Dicotyledons, whose stems increase in 

 thickness by the formation of concentric layers of new 

 wood between the old and the bark ; whose leaves have 

 branched veins; and whose seeds have two separate 

 germs — one for the stem, the other for the root. 



This class includes most of the trees, bushes, and her- 

 baceous plants of temperate climates. 



2. Endogens, or Monocotyledons, whose stems increase 

 longitudinally, without becoming much thicker; whose 

 leaves have parallel veins; and whose seeds have but 

 one germ. Palms, Aloes, Grasses, and most bulbous- 

 rooted plants belong to this class. 



3. Acrogens, or Cryptogenic Plants, which differ from 

 both the other classes in almost every particular. They 

 have neither stems, leaves, flowers, nor seeds, properly 

 so called, but have instead differently constituted organs, 

 answering the same purposes. 



All nowerless plants, from the large Tree-ferns of the 

 tropics to the minute one-celled Algae of our ponds and 

 ditches, are included in this class ; and there is in conse- 

 quence much greater difference between the organiza- 

 tion of its highest and lowest forms than is to be found 

 in either of the preceding classes. 



Dr. Lindley, in his f Introduction to Botany/ divides 

 Acrogens into six Alliances, which he calls respectively, 

 Filicals (Ferns, etc.) ; Lycopods (Club-mosses and Pep- 

 perworts) ; Muscals (Mosses, etc.) ; Lichens ; Fungals 



