ELEMENTS OF STRUCTURAL BOTANY. HI 



wliicli produce flowers of some kind, and those which <h 

 not, and to each of these great groups we shall give the 

 name Series. AVc thus have the Flowering, or, to 

 use the Greek term, Phanerogamous, Series, and the 

 Flowerless, or Cryptogamous, Series ; or we may 

 speak of them hriefly as Phanerogams and Crypto- 

 gams. Then, leaving the Cryptogams aside for tne 

 moment, we may break i;p the Phanerogams into two 

 great Classes, Exogens (or Dicotyledons) and 

 Endogens (or Monocotyledons), for reasons al- 

 ready explained. By far the greater number ot Exogens 

 produce seeds which are enclosed in a pericarp ol some 

 kind ; but there is a remarkable group of plants (repre- 

 sented in Canada only by the Pines and their imme- 

 diate relatives) which dispense with the pericarp alto- 

 gether, and whose seeds are consequently naked. So 

 that we can make two Sub-Classes of the Exogens, on 

 the basis of this difference, and these we shall call the 

 Angiospermous Sub-Class, and the Gymncsper- 

 mous (naked-seeded) Sub-Class. The first of these, 

 may be grouped in three Divisions, the Pohjpetalous, 

 Gaviopetalous, and Apetalous, and the Endogens aiso 

 in three, the Spadireons, the Petaloideous, and the 

 Uiumaceous, types of which we have already examined 

 in the Marsh Calla (spadiceous), Trillium (petaloideous), 

 and Timothy (glumaceous), and the distinctions between 

 wiiich a,re sufficiently obvious. ■ 



The Cryptogams are divided into three great 

 Classes, viz. : Acrogens, embracing Ferns, Horse- 

 tails and Club-mosses; Anophytes, embracing Mosses 

 andLiverworts; and Thallophytes, embracing Lichens, 



Seaweeds, and Musin-ocms. 



