EXPLANATION OF THE ILLUSTRATION 
Ficure l. Entire plant of peyote (Lophophora Wil- 
liamsii (Lem.) Coult.) showing details of the chlo- 
rophyll-bearing erown of the plant. Variation in 
the number and appearance of the ribs has given 
rise to much confusing taxonomic controversy, but 
this thirteen-ribbed form is typical of older plants. 
It is this crown which, when cut from the root and 
dried, is known as the mescal button, two of which 
are illustrated in figure I]. Natural size. 
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