78 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



good morphologic mark of stems, he is constrained to offer the 

 category of what he calls smooth-stemmed plants. Such 

 "stems" are nothing more or less than the flower-stalks of 

 acaulescent perennials, called smooth stems because devoid of 

 those unevennesses now designated as the nodes and internodes, 

 and received as the most universal mark of real stems. His 

 examples of the smooth stem are those of the onion and leek, 1 

 good illustrations of the scape, as named and denned in later 

 organography. 



The leaf is a thing so almost infinitely diversified that he does 

 not attempt to characterize it morphologically, or even physi- 

 ologically, for he can not with any degree of certainty name its 

 chief function. So without vouchsafing any definition of it, he 

 goes about the rehearsal of its many aspects. Although as an 

 organ it heads the list of that division of them which he has dis- 

 tinguished as transitory, and therefore in a manner secondary, no 

 part of a plant would seem more deeply to have interested him, 

 or to have been more carefully observed. He is even somewhat 

 diffuse in his writing upon it ; more so than in the case of any other 

 organ, unless the fruit and seed are to be excepted; and, since the 

 opinion now prevails almost too widely that little was done in the 

 direction of plant organography until within the last two centuries, 

 the interests of truth can not at just this point be better subserved 

 than by giving the substance of this ancient Greek's morphology of 

 the leaf somewhat in detail. 



" Leaves are commonly attached to the stem or branch or to 

 whatever else supports them, by a stalklet; this either firm and 

 holding the leaf steadily in a certain position, or else slender and 

 feeble, allowing the leaf to hang downward and perhaps tremble 

 with the passing breeze, or even to become inverted, turning the 

 usually paler lower face upward. But there are also leaves with 

 no stalklet, these adhering directly to the branch. Some leaves 

 arrange themselves only in opposite pairs, with regular intervals 

 between the pairs, while others are scattered singly and without 

 order up and down the stem." 



It will be seen that these beginnings of Theophrastan teaching 

 about the leaf are precisely what one finds in every primer of 

 botany to-day. Every beginner has to be taught the importance 

 of the distinctions between a petiolate leaf and one that is sessile, 

 and between the opposite and the alternate in leaf arrangement. 



1 Hist., Book i, ch. 16; also Book vii, ch. 7. 



2 Excerpts from Hist., Book i, ch. 16. 



