METHODS 



Six archeological (Table 1) and thirty recent (Table 2) leaf 

 specimens of the cultivated cocas were prepared for microscopic 

 examination. All of these leaves were cleared in a 5% aqueous 

 solution of NaOH, either at room temperature (archeological), 

 or in an oven at ca. 70° C. (recent). Cleared leaves were stained 

 with a 1% solution of safranin in 50% ethanol for several days, 

 then dehydrated with ethanol, treated with xylene and mounted 

 permanently on microscope slides in Canada balsam. Recent 

 leaves also were prepared for paraffin sectioning by con- 

 ventional methods of botanical microtechnique. To obtain 

 epidermal sheets for stomatal examination and counts, leaf 

 fragments were macerated in Jeffrey's macerating solution 

 recipe from Johansen (1940). 



Numbers of freely terminating veinlets and stomata per mm^ 

 of leaf surface were microscopically determined, using 10-20 

 counts per leaf or leaf fragment. Stomatal counts and maximum 

 guard cell lengths were measured either from cleared leaves 

 (archeological) and/ or macerated leaf epidermal sheets (recent). 

 In order to provide a reliable comparison of their stomatal 

 systems, the stomatal density (i.e. number per mm^) was 

 corrected for relativistic differences in guard cell length among 

 different specimens. Since stomatal size and relative number per 

 unit of leaf area typically are inversely interrelated (Rury, 1981, 

 1982), it was necessary to calculate the percentage of leaf surface 

 occupied by stomata (i.e. stomatal frequency) for comparative 

 purposes. This calculation thus integrates guard cell length and 

 stomatal density into a single, standardized measurement, which 

 is especially useful when working with leaf fragments. 



Leaf venation terminology has been simplified as much as 

 possible, but follows that of Mouton (1970) and Hickey (1973) 

 with necessary additions and modifications. 



Illustrations were prepared using several techniques. Negative 

 prints of foliar venation patterns of recent coca leaves were 

 prepared by placing cleared leaf slides directly in the photo- 

 graphic enlarger (Dilcher, 1974). Line drawings of foliar 



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