_b._ Pores of spring wood small to minute.
_a."_ Lines of pores in summer wood fine, not as wide as the intermediate s.p.a.ces, giving rise to very compact grain ROCK ELM.
_b."_ Lines of pores broad, commonly as wide as the intermediate s.p.a.ces .........................WINGED ELM.
_c._ Pores in spring wood indistinct, and therefore hardly a ring-porous wood .................................CEDAR ELM.
[Ill.u.s.tration:
Fig. 138. Wood of Elm.
_a_ red elm; _b_, white elm; _c_, winged elm.]
[Ill.u.s.tration: Fig. 139. Walnut. _p.r._, pith rays; _c.l._, concentric lines; _v_, vessels or pores; _su. w._, summer wood; _sp. w._, spring wood.]
[Ill.u.s.tration: Fig. 140. Wood of Cherry.]