32 
THE FLORISTS JOURNAL. 
are not generally found in any part which is formed in a down¬ 
ward direction, and are therefore usually absent from the wood, 
the bark, and the roots : as exceptions to this general rule may 
be mentioned Nepenthes , where they abound in the bark and pith, 
and some few seeds, of which they form part of the testa, or 
covering. They are, for the most part, altogether absent in 
flowerless plants, and hence is founded one of the grand divi¬ 
sions of plants into Vasculares and Cellulares, the only excep¬ 
tions being in the case of Ferns and Lycopodiaceag, which are 
the connecting links between phanerogamic and cryptogamic 
plants. It has been supposed by some botanists, that the spiral 
vessels terminate in the orifices of the cuticle called stomata ; 
but this supposition is without any solid foundation. Ducts are 
also membranous tubes, with conical or rounded extremities, 
and differ from spiral vessels principally in their incapability of 
being unrolled without breaking: owing to this close analogy, 
they are by some persons still confounded with spiral vessels ; 
but it seems to be desirable to view them as distinct organs, 
because they occupy a station in which true spirals are rarely 
found, and we may, therefore, without injustice, infer, that their 
office and functions are somewhat different. Their variations of 
form are designated, the closed, the annular, the reticulated, the 
scalariform, &c. 
Woody Tissue is also composed of slender, transparent, and 
membranous tubes, tapering to each end, laying in bundles, and 
having no direct communication with each other except by in¬ 
visible pores. It is nearly allied to cellular tissue, being by 
some botanists considered as a mere elongated form thereof; 
but a sufficient difference may be discovered in its attenuated 
character, and also its tenacity. It is this latter character which 
renders it suitable to be manufactured into linen, the strength of 
which, as compared with that of cotton fabric, which latter is 
mere cellular tissue, consists solely in the tenacious character of 
woody tissue. There are three distinct kinds of woody tissue, 
of which the finest and most common, as well as most genuine, 
is destitute of granules adhering to the sides of the tubes ; an¬ 
other form of woody tissue has these appendages , and approaches 
near the character of vasiform tissue; whilst a third kind, 
termed the glandular , is almost exclusively confined to the stems 
of Conferee. This latter differs from granular woody tissue, 
in the markings of the tubes being vesicular, and usually trans- 
