Up Primary xylem Oak wood Leaf vein Vein ends Bean seed Pine tracheids, xs Fern TE, xs Fern, TE, mag Annular walls Annular, stretched Annular, narrow Scalariform walls Scalar., narrow CBP, pine CBP, dicot CBP, irregular Contact faces Pits, side view CBP, pine, xs CBP,angio, xs CBP, fern, xs Contact face, xs Simple perf. plate 1 Simple perf. plate 2 Pitted perf. plate Perf. plate & helix Perf. plate, face Perf. plate, mag Perf. plate, section Perf. plate rim Perf. plate & wall Scalariform Per plate Primary xylem Vessel sizes Fern TE Pine needle VE precursor, ls Protoxylem 9 Contact faces VE precursor, xs Precursor 2 Torn vessel Torn vessel 2
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Fig.
7.4-4.
Transverse section of a needle leaf of pine. Pines and other conifers lack
vessels completely, so the xylem in this pine leaf must consist of tracheids,
not vessels. Notice that these tracheids are smaller
than the surrounding parenchyma (in the upper left corner) and not
much larger than the phloem cells at the bottom of the micrograph.
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