with an acute and conspicuously mucronulate apex; (2) E. Coca 

 var. Ipadu, broadly elliptic, with an acute to obtuse con- 



var. 



spicuously mucronulate apex; (3) E. novogranatense 

 novogranatense, oblong to oblong-elliptic (rarely obovate), with 

 an obtuse to rounded or emarginate, rarely mucronulate apex; 

 and (4) E. novogranatense var. truxillense, narrowly elliptic to 

 lanceolate, with an acute, minutely mucronulate apex. Although 

 foliar form is more or less diagnostic for particular coca 

 varieties, the full range of variation among the leaves of the four 

 varieties constitutes a continuum of shapes and sizes (Plate 39). 

 Isolated leaves and leaf fragments, therefore, cannot be reliably 

 identified on the basis of leaf form and size alone. A 

 combination of both macro- and micromorphological features is 

 required for accurate taxonomic identifications of coca leaves. 

 The central panel, demarcated by a pair of abaxial "lines" 

 (anatomically, collenchyma ridges; Rury, 1981) running parallel 

 to and on either side of the midvein, is of variable occurrence 

 and prominence among the cultivated cocas. The central panel 

 may be conspicuous, due to its markedly finer and less 

 prominent vein reticulum in E. Coca var. Coca and E. 

 novogranatense var. novogranatense. but often is very faint or 

 entirely lacking in some leaves of E. Coca var. Ipadu and E. 

 novogranatense var. truxillense. owing to overall uniformity of 

 the vein reticulum throughout the leaf. Statistically significant 

 differences may occur in both stomatal and veinlet termination 

 numbers, within versus outside of the central panel, when this 

 feature is prominent in leaves of each variety (Rury, 1982). 

 Careful attention, therefore, must be given to the position in the 

 leaf at which such data are gathered. 



The primary vein (midvein) is of moderate diameter and 

 follows a straight course from the leaf base into its apex. The 

 basic venation patterns vary moderately, both within and among 

 coca varieties, ranging from eucamptodromous to brochido- 

 dromous, with a festooned system of intramarginal, loop- 

 forming veins and veinlets (Table 4). Leaves of £.' 



granatense var. truxillense (Trujillo coca) are the most variable 

 of all varieties in their overall venation pattern, which may range 

 between the eucamptodromous type characteristic of both 



novo- 



307 



