4 BULLETIN 1050, IT. S. DEPARTMENT OF AGRICULTURE. 
I. Wood light to dark reddish brown — Continued. 
B. Pores do not contain a reddish gum — Continued. 
1. Pores readily visible, etc. — Continued. 
BB. No white tangential lines consisting of rows of ducts, 
but numerous very fine continuous lighter-colored lines 
of soft tissue present, 120 to 175 per inch of radius, 
barely visible without a magnifying glass. Wood 
moderately heavy. ' 
" Colombian mahogany " (Carinian-a pyriformis). 
CC. No fine light-colored tangential lines present; struc- 
ture very homogeneous. Color light purplish brown. 
Wood moderately light and soft. 
" Liberville mahogany " (BosiueUia klaincana). 
2. Pores not readily visible without a lens. 
AA. Pores barely visible without a lens on smoothly cut sur- 
faces in good light; very distinct under a lens. The 
heartwood is dull reddish brown ; the wide sapwood is 
white. The wood is heavy, usually straight-grained. 
Sweet birch (Betula lenta). & 
Yellow birch {Betula lutea). 
BB. Pores not visible without a lens; very small and uni- 
formly distributed as seen with a lens. The heart- 
wood is reddish brown, often with darker streaks; 
the wide sapwood is pinkish white (unless blued by 
stain). The wood is moderately heavy and usually 
has interlocked grain. 
Red gum (Liquidambar styraciflna). 
II. Wood without reddish tinge. Color creamy white to yellowish brown. 
Growth rings sharply but not conspicuously defined by white tan- 
gential lines or by a slightly darker band of summerwood. Pores 
of practically uniform size throughout growth ring, barely visible 
on a smoothly cut end surface, but very distinct as fine grooves on 
planed longitudinal surfaces : mostly filled with tyloses. Wood 
with interlocked grain and moderately heavy. 
"White mahogany." or primavera (Tabebuia donnell-smithii). Q 
Note. — The sapwood of birch is without reddish tinge, and when taken by itself might 
be classified under " II " above, although fresh cuts are almost white. For means of 
distinguishing birch from primavera. see descriptions of these species. 
DESCRIPTION OF SPECIES. 
TRUE MAHOGANY.- 
Sirietenia matiagoni Jacq. 5 ; Swietenia macrophyUa King.; Sirietema cirrhata 
Blake; Swietenia humilis Zucco. ; Sicietenia cancloUei Pittier. 
Mahogany Family (Meliace.e). 
OTHER NAMES. 
True mahogany comprises all the species of the botanical genus f 
Sicietenia. of which five are known at present. 
4 See r. S. Dept. Agr. Bulletin 474, " True Mahogany, - ' by C. D. Mell. For sale by 
Superintendent of Documents, Government Printing Office, Washington. D. C. Price, 
5 cents. 
5 The name after a scientiflc name is usually an abbreviation of the name of the person 
who first described the species. 
6 Blake, S. F.. " Revision of the True- Mahoganies." Journal of the Washington Acad- 
emy of Scionces. vol. 10. pp. 286-207. f. 1-2. 
