The Trees of Texas 21 
these terms, when his decision will be in favor of ‘‘IL.”’ Then he 
must determine whether the leaves are opposite or alternate on 
the stem. Here his decision goes to ‘‘B,’’ leaves alternate. Under 
‘*B,’’ the choice goes to ‘‘2,’’ leaves with ‘‘netted veins,’’ then to 
“bh *? ‘leaves with only one primary vein at base.’’ The next 
choice is between ‘‘leaves entire and blade of leaf serrate or 
notehed,’’ ‘‘(1)’’ or ‘‘(2).’’ Im this case the second is found 
correct. After this the choice falls on ‘‘(a),’’ ‘‘veins of leaves 
straight,’’ not prominently branched then ‘‘y.’’ Trees not thorny 
II. Leaf Edges. 

{ 
1 
\ 
oe 
\ 
1. Serrate (saw-toothed). 
Dentate (toothed). 3. Crenate (scalloped). 
4, Undulate (wavy). 
Sinuate (bayed). 6. Incised (jagged). 
2 
5. 
~ and finally ‘‘(x)’’ leaves oblique at base, and ‘‘m’’ fruit a 
circular samara, leaves harsh to the touch. This leads unerr- 
ingly to the genus Ulmus, and no other tree in our flora ean be 
placed here if the observations are carefully made and each deci- 
sion accurately drawn. Turning to the page reference a descrip- 
IiI. Leaf Tips. 

1. Acuminate. 2. Acute. 3. Obtuse. 4. Truncate... 5. Retuse. 6. Emar- 
ginate. 7. Obcordate. 8. Cuspidate. 9. Mucronate. 
tion of the genus is given. Here again the student should check 
each statement in the description, to see if it tallies with the speci- 
men at hand. If correct, the key to the genus must next be con- 
sulted. Here the choice goes to ‘‘flowers opening in the spring 
before the leaves.’’ ‘‘Branches not corky winged.’’ ‘‘ Leaves 
smooth or somewhat roughened above, inner bark not mucilagin- 
