1488 ARBORETUM AND FRUTICETUM. PART III. 



In these instances, the pedicel is often a little longer, and the capsules more 

 slender. 



" The colour of the young shoots varies greatly, often so much as to cause 

 the varieties to appear distinct, species. The branchlets of S. alba are either 

 brown, or, as in the var. vitellina, of a yolk-of-egg or a red brick colour; and 

 there is a different shade of yolk-of-egg colour in S. repens, and S. rosmarini- 

 folia (S. lae v ta Schultz). Many species, when carefully examined, will be found 

 to vary in colour, though only to a small extent. The branches of S. purpurea 

 are of a coral colour, rarely of a dark yellow, and sometimes white, covered 

 with a reddish bloom. S. mygdalina has the shoots sometimes of a brownish 

 yellow, and sometimes of a brownish black. 



" The form of the leaves in the same species, and even in the same plant, can 

 never be depended upon. In S. /jhylicifolia, S. w,yrtilloides, S. arbuscula, and 

 S. repens, they vary from narrow-lanceolate and being attenuated towards 

 the base, in the three last-named species, to roundish-ovate and being cordate- 

 emarginate at the base. In some species, the form of the leaves is almost 

 always the same, as in S. viminalis, S. incana, and S. 7/ippophaefolia. In 

 other species, the leaves vary ; being serrated or entire, green or hoary on the 

 under surface, and glabrous or hairy, on the same plant. The same variation is 

 common on the exterior of the ovaries ; which, in jhylicifolia, are some- 

 times glabrous, and sometimes hairy; some individuals of this species having 

 half the ovary hairy, and the other half glabrous; while mothers there is only 

 a hairy or downy line. In certain species, however, these variations are never 

 found, or very rarely ; although in S. viminalis ovaries partly naked, and 

 partly downy, occur. The brown tip of the bracteas of the flowers, in some 

 species, turns paler, and in others red, or even purple ; which is another cause 

 of uncertainty in specific distinctions. The bracteas are sometimes obovate, 

 and only half the length of the ovary ; and sometimes, in the same species, 

 lanceolate, and reaching as far as the style. The style and stigma likewise 

 vary in length, and are occasionally more or less cleft ; yet both these organs 

 afford most useful characteristics. The style often appears shorter from being 

 hidden by the long hairs of the ovary. Stigmas of a rose colour, and of a 

 yellow colour, have been found in the same species. The stipules vary in size, 

 but never in form ; hence they afford the very best characteristics for distin- 

 guishing species. In no species can these be said to be wanting ; and, though 

 on old plants they are often not seen, such plants, when cut down, send up 

 young shoots which produce leaves attended by stipules of an extraordinary 

 size. The buds are always 1-valved; and the valves are often cleft at the tip, 

 and sometimes as far as the base ; though sometimes, on the same individual, 

 they are undivided. The folding of the leaves in the bud is, most probably, 

 constant, although different in the various species : but this I cannot affirm 

 as certain, not having examined the leaf buds of a sufficient number of species. 



"The variation of the different parts is not the only difficulty with which the 

 botanical student, in this genus, has to contend : the great number of hy- 

 brids, the existence of which in the genus Salix no one can doubt, is another 

 obstacle. Nobody will accuse me of arrogance in assuming to know S. rubra 

 and S. viminalis. On the banks of the Redmtz, near Erlangen, there are man} 

 thousand trees of these two species ; and, at the same time, many intermediate 

 forms, which I can refer to neither species. The catkins of these afford no 

 distinguishing marks ; for what seem at one time to belong to the forniei 

 species, at another time appear more nearly allied to the latter." Koch con- 

 cludes by stating that, in his Commentary, the species have been arranged in 

 10 groups ; and that no kind has been admitted as a species that he has not 

 himself seen and examined. He has added but few varieties, " although an 

 immense number of no importance might have been adduced ; being convinced, 

 from daily observation and experience, that the multiplication of varieties, in- 

 stead of rendering any intricate genus more clear, only involves it in a greater 

 difficulty." 



The species of Koch, besides being identified with those of the Species 



