24 Botanists of Germany and the Netherlands [BOOK i. 



matically-allied plants is often so great, that to distinguish 

 them specifically requires consideration and careful com- 

 parison. The resemblance is more obvious than the difference. 

 There are moreover many plants which are entirely distinct from 

 one another in their inner nature, but which appear strikingly 

 alike if we regard the impression produced immediately on 

 the senses, and the converse of this statement is equally true. 

 Hence the attempt to circumscribe and fix individual forms 

 in the act of describing was at once found to involve diffi- 

 culties, the solution of which leads directly to the conception 

 of some kind of arrangement. A comparison of the herbals 

 of Fuchs and Bock up to Kaspar Bauhin shows very plainly 

 how these difficulties were gradually overcome, how the 

 describing of single species led necessarily, and without the 

 intention of the describer, to considerations of a distinctly 

 systematic character. Where the species in a group of forms, 

 which we now designate as a genus or family, closely resemble 

 each other in habit, there arose of itself the instinctive feeling 

 that such forms belong to one another. This feeling asserted 

 itself in words when, as was done from the first, a number 

 of such forms were without conscious reflection designated by 

 the same name ; thus, to mention one of many examples, we 

 find Bock applying the name Wolfsmilk, Euphorbia, not to one 

 species of the genus, but to several, which he then distinguishes 

 by epithets (common, least, cypress, sweet). The customary 

 mode of expression in the herbals is very instructive on this 

 point ; there are, they say, two or more of this or that plant 

 which have not been hitherto distinguished. But this feeling 

 of connection and similarity of kind was produced not only by 

 forms that were closely allied, but also by such as belong to 

 extensive groups of the system ; thus the words moss, lichen, 

 fungus, alga, fern, had long served to include a great number 

 of distinct forms, though the separation of these groups had 

 nowhere in truth been carried out with logical precision. 



These remarks are important as serving to show in the most 



