148 Trees, Stars, and Birds 



figures (i, 2, etc.), and, finally, the groups under some of the 

 figures are split up into divisions with small letters (a, b, etc.). 



How to use the key. Suppose you have a piece of wood 

 and have no idea what it is. The first thing to decide is 

 whether it is a ring-porous or a diffuse-porous wood. Look 

 at your specimen to decide this point. If it is ring-porous, it 

 belongs under I ; if it is diffuse-porous, it belongs under II. 



If you find it is diffuse-porous, the next question to decide 

 is whether it belongs under A, B, C, or D of the diffuse- 

 porous woods. Read the description of A first, and if your 

 specimen does not agree with it, pass on to B, and then if 

 necessary to C and D. If it does not fit under A , it will not 

 fit in any of the smaller groups under A ; so do not waste 

 time on these but pass at once to B, C, or D. 



Suppose now that the pores in your specimen are small 

 and evenly distributed and you decide it belongs under C. 

 The next step is to see whether it belongs under i, 2, or 3. 

 If the pith rays are fine, but yet visible without a lens, your 

 wood belongs under 2. 



The final step now is to determine whether your specimen 

 belongs under a, b, c, d, or e. Let us suppose it is hard and 

 reddish in color. These characters will then identify it as 

 maple. 



In case you think you already know the kind of wood you 

 have, you can use the key backward to see whether you have 

 the correct name for your specimen. For example, if you 

 have a piece of wood that some one has told you is catalpa, 

 you can find the name in the key and see if the description 

 agrees with what you find by examining your specimen. If 

 your specimen lacks the pith, that feature may be neglected ; 

 but to be reasonably sure that it is catalpa you should see 

 that it agrees with I, with A t and with i above the descrip- 

 tion of catalpa, but not with a or b under i. 



