MAHOGANY AND SOME) OF ITS SUBSTITUTES 7 



surface. Wood parenchyma in numerous fine but 

 distinct concentric lines. Wood rather dense ; me- 

 dium-textured. Color rather light reddish brown 

 with purplish tinge; often striped. "Colombian Ma- 

 hogany," Albarco: Cariiiiana pyrifoniiis (Lethyci-. 

 dacese). 

 b^ Wood parenchyma not in very numerous closely spaced tangential or 

 concentric lines; concentric lines, if present, are always or mostly at 

 limits of growth rings. 

 a" Pores and pore-groups surrounded by a circle or patch of paren- 

 chyma of lighter color than the fibers. Vessel lines conspicuous, 

 a" Pores rather large with narrow circles of 'parenchyma which 

 are not confluent; mostly solitary but occasionally subdivided; 

 irregularly disposed with tendency to become ring-porous; 

 sometimes in diagonal chains ; mostly open ; reddish gum 

 present; white substance not observed. Fine concentric lines 

 of parenchyma at limits of growth rings. Rays inconspicuous 

 on radial surface; scarcely visible on tangential even with 

 lens ; sometimes faintly visible on cross section without lens. 

 Ripple-marks absent. Wood hard and heavy but easily 

 worked. Odorless. Color chestnut brown tinged with red ; 

 sometimes striped. Sabicu : Lysiloma sahicii (Leguminosae). 

 b^ Pores small to minute within prominent patches of paren- 

 chyma which are sometimes confluent ; solitary or more often 

 subdivided ; well distributed, without tendency to become 

 ring-porous ; sometimes in diagonal chains ; mostly open ; red- 

 dish gum present ; white substance not observed. Growth 

 rings present but not limited by parenchyma except locally. 

 Rays inconspicuous on radial surface ; scarcely visible on tan- 

 gential even with lens. Ripple-marks irregular ; about 80 per 

 inch. Wood very dense. Odorless. Color dark purplish 

 brown with light-colored vessel lines ; sapwood yellowish 

 white with reddish streaks. T.\marind. Madeira, "Madeira 

 Mahogany": Tamarindus iiidica (Leguminosae). 

 b^ Pores and pore groups not surrounded by parenchyma. Vessel 

 lines visible but not conspicuous. 

 a^ Pores usually indistinct without lens ; numerous and well dis- 

 tributed ; solitary or subdivided : open ; gum deposits and 

 white substance absent. Wood parenchyma in fine concentric 

 lines at limits of growth rings which are usually distinct on 

 longitudinal surface. Rays distinct on . radial surface, indis- 

 tinct on tangential ; often visible on cross section without 

 lens. Ripple-marks absent. Wood hard, of very fine and 

 uniform texture; usually straight-grained. Odorless. Color 

 brown tinged with red or pink; sometimes decidedly reddish. 

 Birch: Betitla Iciifa, B. hifea (Betulaceae). 

 b^ Pores small but distinct without lens ; numerous and well- 

 distributed ; solitary or mostly subdivided ; mostly open ; gum 

 deposits present ; white substance not observed. Wood paren- 



