128 AN INTRODUCTION 



6. FRONS*, is a species of trunk composed of a 

 branch and leaf blended together ; and is frequently 

 united with the fructification ; it belongs properly to 

 the Palms and Filices. 



7. SxiPEsf, is used to express the base or trunk 

 of a Frons, and is applied only to the Palms, Filices 

 and Fungi. 



CHAP. V. 



OF SIMPLE LEAVES. 



LEAVES are to be considered in three respects, 

 viz. 1. as Simple. 2. Compound. 3. Determinate. 

 We shall in this Chapter treat only of the simple. 



SIMPLE leaves are such as have only a single leaf 

 on a petiole. They differ in respect to Circum- 

 scription, Angles, Sinus, Apices, Margin, /Super- 

 ficies and Substance. 



CIRCUMSCRIPTION considers the form of the cir- 

 cumference of leaves where there are no angles or 

 sinuations : In which respect leaves are, 



Orbiculate, round; when the longitudinal and 

 transverse diameters are equal, and the circumference 

 circular. 



Subrotund, roundish ; when the figure is nearly 

 orbiculate. 



Ovate, egg-shaped ; when the longitudinal diame- 

 ter exceeds the transverse; and the base is circum- 



* There is no expression answerable to this term in our 

 language. See the Notes at page 43. 



f The word in its proper signification means a trunk or 

 stock of any plant. But the sense in which the term is re- 

 ceivecl in Botany is as here explained : It is used also to ex. 

 press the thread or fine trunk that supports the pappus in 

 downy seeds. See Part I. Chap. 7. 



