SECT. I. OBGANOGRAPHY AND GLOSSOLOGY. "5 



most striking and important, and are obtained by 

 making a trfensverse section through the leaf-buds of 

 different plants : a, plicate ; b, equitant ; c, imbricate ; 

 d, involute ; e, revolute ; /, obvolute ; g, circinate. 



(82.) Disposition of Leaves. Although the term 

 " radical leaves," is applied to those which are seated 

 close to the ground, and appear to spring from the 

 summit of the root itself, yet all leaves do, in fact, 

 originate upon the stem or branches. In a general 

 way we may refer their disposition to one or other of 

 two modes : either " verticillate," when more than 

 one is attached to the stem at the same altitude, or 

 about the same horizontal plane ; or " alternate," when 

 they are so dispersed upon the stem that no two are 

 seated precisely in the same horizontal plane. When the 

 number of leaves in the same plane does not exceed two, 

 and these lie on contrary sides of the stem, they are said 

 to be " opposite." Leaves are frequently so arranged, 

 one above another, as to form two or more ranks down 

 the stem ; and sometimes they appear to follow the 

 direction of spiral lines which coil round it. These 



different appearances receive appropriate names in de- 

 scriptive botany, which it does not fall in with our 

 plan to dilate upon ; but, before we have concluded this 



