himself represents all the botanical knowledge of our day. By 

 these has been established the present aim of botanists, to explain 

 by a universal knowledge of vegetation its universal affinities and 

 laws, accepting the principles of Linnaeus and the method of Jussieu 

 as the ground and starting-point of their researches. We proceed, 

 then, in the determination of a plant, from a view of the whole 

 structure and organs, to compare it first with all other plants, in the 

 great Divisions ; next with the larger groups, in the Classes ; then 

 with the lesser groups, in the Orders ; then with the yet more defi- 

 nite Genera, and finally with the other species of the genus to 

 which we have thus reduced it. From its remotest affinities we 

 descend to its nearest, effecting the whole through the means of 

 the characters of each division. This is our way of using the sys- 

 tematic manuals of the Natural Method ; but there are some further 

 remarks to be made, respecting the Method itself. 



How far, asks Wahlenberg, can we simply follow nature, and 

 where must art come in ? From species, those definite quantities 

 of nature, from which we start, we at once reach the perception of 

 certain affinities which are formerly expressed in the notion Genus ; 

 and, indeed, in the systematic study of plants we arrive at this 

 notion by the mere mechanical constraint of scientific form, a spe- 

 cies in science being always a species of some kind or group. From 

 Genus we may even proceed to Order or natural family, but to look 

 beyond above this, hie Za&or, hoc opus. 



The difficulties of the remoter affinities belong more properly to 

 the province of others ; nor is it necessary to refer to them here, 

 any further than simply to state what we know of a law of nature 

 which concerns all plants, and seems to indicate a harmony which 

 will never admit of complete expression in a system. tt Do not all," 

 says Coleridge, " press and swell under one attraction, and live to- 

 gether in promiscuous harmony, in the immediate neighbourhood 

 of myriad others that in the system of thy understanding are dis- 

 tant as the poles ? " That the series of nature and of plants is not 

 simple, neither as respects all plants, nor as respects particular 

 groups ; that the deviations observable from particular types do not 

 form a single, but more, series ; and therefore that there is much 

 conspiring to the suggestion of centres, central types, and diverg- 

 ing or converging radii, is now generally admitted by botanists. 

 Some further illustrations of this will be found in what follows, but 

 so little is definitely known of the series of nature, and the attempt 

 to represent them systematically otherwise than as combined in 

 a single series has so rarely been made, that the most guarded 

 language is required to express truly, as I have attempted above, 

 the tenor of what I think is admitted. 



But we have before us the system of Oken, the elements of 

 which were proposed by that philosopher in 1810, and upon these 

 the Systema Mycologicum of Fries elaborated in 1821, though, if I 

 mistake not the first application of his principles, in detail, by the 

 author himself is in his work now to be noticed, which appeared 

 from 1839 to 1841.1 



1 Allgemeine Naturgeschichte ftlr alle Stande von Professor Oken. Stutt- 

 gart. 1839 - 1841. Vol. I. II. III. 1. 2. 3. 



