fjr--^^~IiM'n 



Vvl5 '.V.-'AVfl 



Wlt<Hri'akii!^^!^aiM 



<3/>lV 



JtV 



PLATE XI. THE STRUCTURE OF WOOD. 



1. Cross section uf six-year uld stem of White Piue sbowing (b) bark, (vt cambium, (ar) annual 



ring, (p) pitb, and (rp) numerous small circular rpsin passages, natural size. 



2. A resin passage with bounding epithelial cells, enlarginl. 



3. N^n-porous wood of White Pine showing (spw) spring wood, (sw) summer wood, (ar) annual 



riug, and (rp) resin passage, s 3. 



4. King-porous wood of Chestnut, x 2. 



5. Iting-porous woo<l of Red Oak, showing large medullary rays, x 3. 



6. Diffuse-porous wood of Beech, x 4. 



7. Block of Chestnut wood showing (cs) cross section, (rs) radial section, (ts) tangential section, 



(spw) spring wood, and (sw) summer wood, natural size. 



