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groups, a woody portion or xylem, and a less solid portion, the | ies 
bast or phloém (Fig. 93). The xylem is composed of paren-~ bie ; 
chymatous cells, wood-fibres, vascular cells, and true vessels, 
the walls of these various elements being generally | 
thickened and lignified. The phloém, on the other hand, ‘ane 
consists of succulent and mostly thin-walled masses of — — 
parenchyma and sieve-tubes, in addition to which are Bete 
usually bast-fibres massively developed and strongly =~ 
thickened. Any of these elements of the xylemand phloém 
may, however, be wanting. : 
Narrow thin-walled elongated succulent cells, often found in con- — c 
Fic. 94.—Transverse section through the root of sarsaparilla; sf parenchyma of the “i 
root-sheath ; BZ bast-parenchyma ; B g bast-vessels ; G vessels. (x 200.) = — | 
stood, have been termed caméiform tissue or permanent cambium. © | 
_ Cambiform tissue, latticed cells, and sieve-tubes form, together with. Be} 
