chap. cm. .swuca'ck.*:. SAL1X. 1*89 



Plantarum of Linnaeus, and the Species Plantarum of Willdenow, have the 

 synonymes of other authors added to them. 



In our App. iii. to the genus Salix will he found the characters of Koch's 

 10 different groups; and under each the names and synonymes of the species 

 which he has assigned to them. 



From the perusal of Koch's observations, two points, we think, will be ren- 

 dered clear to the botanical reader : — 1. That the mode of arranging the 

 sections according to the character of the leaves, adopted by all the Linnaean 

 school previously to the time of Wahlenberg, is altogether defective ; and, 

 2. That the system of throwing the species into natural groups, as adopted by 

 Wahlenberg, Fries, Koch, and Borrcr, is the true one. Being ourselves of 

 this opinion, the only question that remained for us to decide was, whether 

 we should follow Koch or Borrer in the arrangement of the species described 

 in this work as in a living state in British gardens. 



The excellence of Koch's system was strongly impressed on our mind 

 from the moment that we saw it developed in Dr. Lindley's Synopsis of the 

 British Flora ; and, if we could have classed all the numerous sorts of willows 

 in the salietum at Woburn, and in the Hackney arboretum, under Koch's ten 

 groups, in a manner satisfactory to ourselves, we should have done so; the 

 more especially as, from observing with care all the different sorts in the 

 Hackney arboretum, at different periods, from March to December, 1836, we 

 felt convinced in our own mind that by far the greater number of them were 

 varieties, and chiefly of S. caprea L. Not being able to do this, we determined 

 on endeavouring to obtain the advice and assistance of the first authority in 

 Britain on the subject of willows; and we accordingly applied to Mr. Borrer, who 

 at once, in the most kind and liberal manner, classed the sorts contained in the 

 Salietum Woburnense in the 22 groups into which, with the exception of a few 

 sorts, they are thrown in the following article. Mr. Borrer's knowledge 

 of this genus is universally known. He possesses an extensive collection of 

 living plants, which he has cultivated for some years ; and, as Sir W. J. Hooker 

 remarks, " No one has ever studied the willows, whether in a growing or a 

 dried state, more deeply, or with a less prejudiced mind." (Brit. FL, ed. 3., 

 vol. i. p. 416.) 



The botanical details which we have given of each particular species, in- 

 cluding a comparison of specimens obtained in a living state from the arbo- 

 retum at Flitwick, from that at Goldworth, and from the salietum at Messrs. 

 Loddiges's, were made out for us, with great care and industry, by Mr. Denson. 

 Our figures were chiefly drawn for us by Mr. Sowerby, from specimens received 

 from the salietum at Woburn Abbey; in the single instance of the S. caprea, 

 reduced from Host's work; and nearly all the remainder, including all the 28 

 plates of leaves of the natural size, by the kind permission of the Duke of 

 Bedford, have been copied from the Salietum Woburnense. 



It will thus appear that our article, lengthy and elaborate as it is, is, in a 

 botanical point of view, chiefly to be considered as matter for a history of 

 willows, rather than as a complete history in itself. Such a history, indeed, 

 can only be prepared by a botanist who has had all the species in a living state 

 under his eye for several years ; and who has applied to them one general 

 principle of contrast or comparison. Till this is done, not only with the genus 

 Salix, but with every other genus of which there are numerous species, a 

 decided imperfection must ever be found in works like the present, in which 

 the specific characters are necessarily made up of descriptions given by dif- 

 ferent individuals, at d fftrent times, and in different countries ; some from 

 living plants collected from their native habitats, others from living plants 

 grown in gardens, and many from dried specimens. All this shows the great 

 advantage that would result to botany and arboriculture from a national 

 arboretum; in which not only all the species and varieties should be col- 

 lected, but also both the sexes of all the kinds that have the male and female 

 flowers on different plants. Such an arboretum, on a sufficiently large scale, 

 and properly managed, would form a living standard of reference, both for the 

 botanist and the cultivator. 



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