4.S. .! > , CaLcvRAix'i Expkrimkx'r Station 
. >/,v SUMAC (Rhus cismontana) 
The ^sinnac 63.) of Colorado is a shrub 3 to 7 feet high. 
'File compound leaves have numerous finely-toothed, smooth leaf¬ 
lets that are whitish beneath. The inflorescence is dense and spheri¬ 
cal. d'he fruT is one-seeded and covered with reddish hairs. The 
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leaves turn bright red in the autumn. It is found throughout the 
•^^tate at lower elevations, usually forming thickets. 
The red fruit of sumac is considered poisonous by some. No 
cases of poisoning, however, have been brought to our attention. 
WESTERN POISON IVY, POISON OAK (Rhus rydbergii) 
W'estern poison ivy (fig. 64), or poison oak, is the only plant 
in the Rocky Mountain region that is noisnnous to the touch. It 
is a low shrub, i to 2 'feet high. Unlike the eastern poison ivy, it 
does not climb or creep. The leaflets come off in threes and when 
young are folded along the midrib, and quite frequently tinged with 
