66 PALMATE-RETICULATE VENATION [CH. V 



from the petiole, but only the midrib, and perhaps the 

 lateral primaries nearest to it in their course, reach the 

 tips of the lobes or the margin ; the outer or basal 

 laterals take a sinuous course and branch or dichotomise 

 before reaching the margin, and then break up in various 

 ways, e.g. Ivy (Fig. 24). This variety is aptly described 

 as palmate-reticulate. 



It is not always possible to refer the venation of a 

 leaf to any single one of the above types, and we then 

 have recourse to compounds of two or more, or we have 

 to refer approximately to one or other of the types. 



