LANDMARKS OF BOTANICAL HISTORY GREENE IO5 



not fail to note that it is the leaf peculiar to the mature and fruiting 

 ivy bush, not that of the rooting and climbing young plant; for 

 the leaves of this are too broad to represent the ovate, and are 

 angularly lobed. 



Note now certain points of agreement among these four leaf- 

 outline types, (i) All are leaves of trees; for few herbaceous 

 plants display such tmiformity of foliage as to the individual speci- 

 men. There is apt to be one form and size of leaf near the base of 

 such a stem, and another widely different description of leaf at the 

 summit, with intermediate forms up and down between base and 

 summit. With some notable exceptions— of which the Greek 

 takes advantage here and there — leaves of herbs do not answer 

 the purpose. (2) The trees are all selected from among such as 

 are most universally and familiarly known; every one of them 

 common in cultivation. Every civilized Greek of three thousand 

 years since knew the sweet bay, the olive, the pear tree, the ivy. 

 (3) The leaves of them all have a certain firmness of texture, either 

 leathery, or approaching it. By this prevision any soft herbaceous 

 plant having lanceolate entire foliage may be described as to its 

 foliage by merely saying that its leaves are like those of the laurel, 

 but thin. (4) The leaves of all four of the types are entire : whereby 

 the leaf that is of lanceolate cut, coriaceous texture, and entire 

 margin, no matter in what genus it may occur, may be described 

 by simply saying that it is the leaf of the laurel. Supposing, 

 however, that a tree is to be described the leaves of which are 

 lanceolate, coriaceous, but with margin serrated, then its descrip- 

 tion as to leaf will be, that it is like the laurel leaf, but serrated. 

 And this selecting of types that have entire leaves is manifestly 

 better than it would have been to have selected serrate leaves for 

 types. In such a climate as that of the Mediterranean, evergreen 

 trees and shrubs predominate, all of them with coriaceous foliagei 

 the kinds with entire leaves being very notably in excess of those 

 having toothed or serrated leaf-margins; therefore the choosing of as- 

 many entire-leaved types as he could was natural to a man in Theo— 

 phrastus' place and environment, as well as making for economy 

 of time and space in describing things. It was by no means acci- 

 dental that this descriptive botanist selected the olive,, the sweet 

 bay, the myrtle tree, and the box as patterns of leaf outline to be 

 referred to in his ph3rtographic work. ^ 



How well such a system of morphologic types is adapted to the 



J See also Dr. Hugo Bretzl, Botanische Forschungen des Alexander zuges^ 

 pp. 8-22, 



