1488 ARBORETUM AND FRUTICETUM. PART 111. 



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

 sleneler. 



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

 tlic varieties to ap[)ear distinct species. The branchlets of S. hWn arc. either 

 l>rown, or, as in the var. viteilina, of a yolk-of-cgg or a red brick colour; and 

 tlicre is a different shade of yolk-of-egg colour in S. repens, and S. ;osniarini- 

 folia {S. hc^ta Sc/ni/lz). Many sjjccies, when carefully examined, will he found 

 to vary in colour, though only to a small extent. The branches of S. [)ur|)urea 

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

 with a reddish bloom. .V. wm^gdi'lina has the shoots sometimes of a brownish 

 yellow, and sometimes of a brownish black. 



" The form of tiie leaves in the same s[)ecies, and even in the same plant, can 

 never be dejiendeil upon. In S. ^^hylicifulia, S. wyrtilloides, S. arbuscula, and 

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

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

 emarginate at the base. In some specic-s, the form of the leaves is almost 

 always the same, as in S. viminalis, .V. incana, and »*>. /nppophaefolia. 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 .V. ^;h} licifolia, are some- 

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

 half the ovary hairy, and the other half glabrous; while in others 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 j)artly naked, and 

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

 sj)ecies, 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 lengtli, and are occasionally more or less cleft ; yet both these organs 

 atibrd most useful characteristics. The styled often appears shorter from being 

 iiidden 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 aflfbrd 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 wliich produce leaves attended by stipules of an extraordinary 

 size. The Imds are always 1-valved; and the valves are often cleft at tiie 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 dirterent parts is not the only difficulty w ith which the 

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

 brids, the existence of which in the genus SiiWx 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 Hedmtz, near Erlangen, there are many 

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

 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 formei 

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

 cludes by stating that, in liis Connncntary^ the species have been arranged in 

 10 groups; and that no kind has l)een 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 convincea, 

 from daily observation and experience, that the nudtiplication 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 witii those of the Species 



