larger stomata, reduced stomatal frequency and higher number 

 of veinlet termini (Table 5). 



Surprisingly, the archeological leaves examined here possess 

 much larger but fewer stomata per unit of leaf surface (i.e., 

 stomatal density) than do modern leaves of the same Trujillo 

 variety. Perhaps the archeological leaves reflect a real difference 

 in the stomatal system of ancient versus recent Trujillo coca, 

 although more samples of both archeological and modern leaves 

 are needed to evaluate this possibility. Alternatively, the 

 combination of large and sparse stomata may merely reflect the 

 inverse relationship between stomatal density and the sizes of 



r 



both individual leaves and their stomata, as previously noted for 

 diverse, pantropical species of Erythroxylum (Rury 1981, 1982). 

 Due to such habitat-related, morphogenetic effects upon mature 

 coca leaf structure (for example, sun- vs. shade-form leaves), the 

 stomatal frequency provides a more reliable basis for compari- 

 sons among coca leaves, since it integrates both stomatal size 

 and density into a single, standard measurement. 



Although the geographic origin of and ecological conditions 

 experienced by the archeological coca leaves are uncertain, their 

 structural conformity with the anatomical profile of modern, 

 drought-adapted Trujillo coca from the arid Peruvian coast 

 suggests that they were grown in a similarly xeric environment. 

 Significantly, the coca leaf (Trujillo) illustrated by Griffiths 

 (1930) also shows drought-adaptive anatomical details char- 

 acteristic of modern Trujillo coca, such as sunken stomata 

 sparsely distributed over the lower epidermis, and a small, 

 lanceolate leaf morphology. This further supports the con- 

 tention (Plowman, in press) that drought-resistent Trujillo coca 

 was being grown at an early date on the desert coast of Peru. 



PROBLEMS IN THE ARCHEOLOGY OF COCA 



In most cases in the past, archeological coca leaves from the 

 Peruvian coast have been identified by both botanists and 

 archeologists as Erythroxylum Coca (var. Coca). Harms (1922) 

 was the first botanist to identify the small-leaved coca from 

 coastal Peruvian sites as E. novogranatense, since he was 

 familiar with the taxonomic studies on Erythroxylum by his 



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