DESCRIPTIVE NOMENCLATURE. 27 1 



PAGE 



The Greek form ' petalos ' 47 



Veins and ribs of leaves, to be usually summed 



under the term 'rib' 5° 



Chemistry of leaves .52 



The nomenclature of the leaf consists, in 

 botanical books, of little more than barbarous, 

 and, for the general reader, totally useless attempts 

 to describe their forms in Latin. But their 

 forms are infinite and indescribable except by the 

 pencil. I will give central types of form in the 

 next volume of Proserpina ; which, so that the 

 reader sees and remembers, he may call anything 

 he likes. But it is necessary that names should 

 be assigned to certain classes of leaves which 

 are essentially different from each other in cha- 

 racter and tissue, not merely in form. Of these 

 the two main divisions have been already given : 

 but I will now add the less important ones 

 which yet require distinct names. 



I. APOLLINE. — Typically represented by the 



laurel 58 



II. Arethusan. — Represented by the alisma 60 



It ought to have been noticed that the character 

 of serration, within reserved limits, is essential 

 to an Apolline leaf, and absolutely refused by an 

 Arethusan one. 



III. DRYAD. — Of the ordinary leaf tissue, 



neither manifestly strong, nor admirably 

 tender, but serviceably consistent, which 

 we find generally to be the substance of 



