52 
REPORT ON BOTANY, MDCCCXLI : 
the woody substance of each joint is separated from the other 
by a layer of cellular tissue ; and that the joints are only con- 
nected with each other by the bark. Decaisne, on the other hand, 
says, that on the contrary, the bark vessels are not connected 
with every joint, and that the latter, on that account, readily 
separate from each other, but that the woody bundles are not 
separated from each other at the nodes ; he failed to detect a 
layer of cellular tissue between them. Eight bundles of long 
fibres, he says, are observed about the pith, which exhibit all 
the characteristics of liber ; these bundles correspond exactly 
with the internal part of the woody bundles, and next to them, 
and even in the wood itself, ringed vessels are found, which 
here seem to occupy the place of the spiral vessels. These 
ring vessels have escaped Kaiser, at least he does not speak 
of them. The mistletoe has no genuine spiral vessels, nor are 
there any traces of a membrane by which they are connected, 
nor are such vessels found in the nerves of the leaves. The 
number of woody bundles is constant in the young twigs, 
generally eight, seldom seven or nine ; each bundle consists of 
three zones, the most external belongs to the liber, or to the 
fibrous cells of the bark, the second to the wood, and the 
innermost is formed like the external. 
What the author calls ring vessels, vaisseaux anneles, are 
not generally so called ; there are genuine spiral vessels, the 
spires of which do not join one another, and in which 
the membrane enclosing them can be distinctly perceived. 
Many Botanists would certainly not agree with him in the 
supposition, that there are spiral vessels which are entirely 
deficient of that membrane ; and it is still less correct, to 
assume that circumstance to be a characteristic sign of spiral 
vessels. The more or less closely connected spires are 
likewise of no particular importance, and deserve as little to 
be ranked among the characteristics of spiral vessels. The 
substance which the author calls liber, certainly seems to 
deserve this appellation ; the wood, however, in this plant is 
of a peculiar quality, which will be explained on another 
occasion, as we shall, further on, allude to the otherwise ex- 
cellent researches of the author on the mistletoe. 
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