STRUCTURAL BOTANY. 23 



monoeciously or dioeciously polygamous, and then inquire 

 for the order in Moncecia or Diwcia. 



62. The quality of the fruit enables us to ascertain the 

 Orders of the classes Did//namia (XIY.) and Tetradyna- 

 mia (XY.) 



63. The Orders of the 24th class, Cry^togamia, are, 

 Natural Orders, 



GENERAL VEGETABLE MORPHO- 

 GRAPHY. 



64, The FORMS occurring'in the vegetable kingdom are 

 not reducible to such strictly mathematical surfaces as are 

 seen in the crystals of rock-salt, common salt, and sundry 

 other minerals. 



In describing the forms of plants, or their parts, we 

 compare them either with simple geometrical figures or 

 with familiar objects, as a bell, a cup, urn, top, etc. 



Of strictly geometrical or mathematical forms, we find 

 in plants perhaps only one — the spherical form of the cell. 



In Botany, regular forms are those which may be 

 divided into two equal parts, by more than one section 

 coinciding with the axis; symmetrical forms, on the other 

 hand, are those which can be divided only by one such 

 section into true halves, each related to the other, like the 

 right and left hand. Thus malvaceous, rosaceous^ cam- 

 panulate corollas are called regular, like a cube, a sphere, 

 etc., in mathematics. A jpapilionaceous jlower, on the 

 other hand, or a ringent corolla, is said to be symmetrical, 



65. All the fokms occunRtNTG in the vegetable king- 

 dom ARE solid bodies — that is to say, they present the three 

 dimensions of space which all solid bodies present — namely. 



