CHAP. cm. 5alica'ce^. .S'a^lix. 1485 



stances of the leaves, the number of stamens, and whether tlie plants are trees, 

 shrubs, or creei)L'rs. With due deference to the opinion thus expressed by 

 the great father of scientific botany, we think that the study of willows, or of 

 any other sjjecies of plant, in its native habitat is by no means a good mode 

 for determining what are species, and what are varieties ; but rather likely, 

 on account of the great difference of habitats, to increase the number of both ; 

 since every difference may be consiilered specific relatively to the circumstances 

 which produce that difference. It appears to us that it would be a better 

 mode to collect plants of the particular genus to be studied from all the dif- 

 ferent habitats in which they are to be fount!, and to cultivate and study them 

 in the same garden, where they would be all subjected to the same exterior 

 influences. What Sir J. E. Sm'ith says on this subject does not appear to ns 

 much more satisfactory than the advice of Linnaeus. " Willows," he says, 

 " .should be particularly studied at three diilerent seasons: the flowering time; 

 the early part of sunnner, when the 30ung shoots, with their stipules and ex- 

 panding' foliage, are to be observed ; and, finally, when the leaves are come to 

 their full size. No botanist, therefore, can be competent to form an opinion 

 about them, unless he resides among the wild ones, for several seasons, or 

 continually observes them in a garden. No hasty traveller over a country, 

 no collector of dried specimens, or compiler of descriptions, can judge of their 

 characters or essential differences. One principle, above all, in this depart- 

 ment of botany, and indeed in every other, cannot be too strictly enforced. 

 We should study a species before we decide on its characters, and not lay 

 down rules of definition beforehand. In many plants, the differences of 

 simple or compound, entire, serrated, or jaggetl, leaves ; the presence or absence 

 of stipules ; though usually so essential and decisive, make no specific dis- 

 tinction at all. In some tribes or genera, one part affords the best specific 

 character, in others some different part. The distinctions of willows are fre- 

 quently so very nice, that the greatest observation and experience only can 

 stamp "them with due authority." {Eng. FL, iv. p. 1G5.) After thirty years' 

 study of everv kind of willow that could be procured in any part of Britain, 

 in the gardenof Mr. Crowe, vshere seeiUings innumerable sprang up all over 

 the sround, ^ir J. E. Snuth was not only confirmcil in the immutability of 

 his species, amounting to G4, as natives of Britain, but also, that new or 

 hybrid species were not produced by the seeds of species growing together in 

 the same garden. Both these conclusions are alike at variance with those of 

 most other botanists. As the result of this eminent botanist's study of the 

 "■enus, he has arrayed his 64 species of British willows under three sections, 

 characteriseil by the margins and surfaces of the leaves; viz. I. serrated and 

 smooth ; 2. entire ami smooth ; and, 3. svn-face shaggy, woolly, or silky. Since 

 the time of Sir J. E. Smith, the [)rincipal British student of willows is Mr. 

 Borrer; and, in Sir W. J. Hooker's lintish Flora, this able botanist has ar- 

 ranged the British willows, increased in Sir W . J. Hooker's work to 71 

 species, under 18 sections. These sections are all natural; and each is 

 characterised by the name of a typical species. This is obviously a very great 

 improvement iii the arrangement of this genus, whether these kinds are con- 

 sidered as chiefly species, or chiefly varieties ; and to us it appears the best 

 adapted for the present state of our knowledge of willows, till all the known 

 kinds shall have been studied for a number of years in one garden. 



Among the Continental botanists, the late Dr. Host of Vienna, and Pro- 

 fessor Koch of Erlangen, appear to be the principal students of willows. 

 Dr. Host, in the preface to his Sallr, seems disposed to consider the kinds of 

 willow that exhibit the same appearances when under the same circumstances 

 of soil and situation as distinct species ; and he has described no fewer than 

 GO of these as natives of Austria. He admits the extreme difficulty of de- 

 termining what are species in many cases, from the different localities in which 

 the same species is sometimes found. For example, willows which inhabit 

 low moist situations in valleys flower only in the spring; while those_ which 

 inhabit mountains ilo not flower till after the melting of the snow, which sel- 



