LANDMARKS OF BOTANICAL HISTORY GREENE 179 



nettles. The specific constituents of his Urtica seem to be 



Urtica dioica, 



Lamium maculatum, 1 



Galeopsis Tetrahit, 



Urtica urens, 



and this, too, is the order in which they succeed one another in the 

 book; first a real nettle, then two so-called dead nettles, the line 

 closing with a second true nettle; a genus composed of two nettles, 

 and two or three members of the very different family of the Labiatse. 

 And this, as intimated above, is a genus not qualitatively but 

 morphologically constituted; a fact easily demonstrable when 

 it is remembered that Brunfels had no anthology; that the flowers 

 of plants not only were not at all understood by him, but were 

 the least and the last parts of them to receive any consideration. 

 So long as two or three herbs were alike as to roots, stems, and 

 leaves, they might easily be designated by the same common, i.e., 

 generic, name. Forgetting, then, all anthologic differences between 

 nettle and dead nettle, note how remarkably they are at agreement. 

 The roots in all are small, fibrous, and not deep-seated. The 

 stems of all are upright, almost or quite without a branch, con- 

 spicuously quadrangular, and the leaves they bear are opposite. 

 'The leaves in all are short-stalked, their blades of the same ovate 

 or oval outline, serrate as to their margins, and are of much the same 

 texture as well as form. The seeds in all for though anciently 

 flowers were neglected, seeds never were the seeds were black, and 

 were always clustered together in the axils of the leaves all up and 

 down the stem. All these quite marked characteristics of all their 

 vegetative organs Urtica and Lamium and Galeopsis have in common. 

 Since the thought is one far from being familiar to the botanical 

 mind of the present, it must here again be insisted on, that the 

 grouping together of several plants upon vegetative characters 

 only, but under a generic name, is as exactly of the nature of a 

 generic concept as that group which is rested on characters of flower 

 and fruit only. By either method a genus may be circumscribed 

 which shall be unnatural ; and the idea is equally the idea of a genus 

 in either case. 



I do not see what chapters of any history of botanical science 

 should be more profoundly significant, or of a more general interest, 

 than those touching upon the development of men's ideas of a plant 

 genus ; for the idea of the genus seems to be first and last the type- 



' But this one not figured, though by implication included, as quoted 

 from Hermolaus Barbaras by Brunfels, on page 154. 



