12 MANUAL OF TROPICAL AND SUBTROPICAL FRUITS 



Mez) is another species which is likely, when known in this 

 country, to be classed popularly as an avocado. 



The two species from which the cultivated avocados are 

 derived are closely alike in many respects. It is easy to dis- 

 tinguish them by the smell of the crushed leaves; those of 

 P. drymifolia possess an aromatic odor, resembling that of 

 anise or sassafras, which those of P. americana entirely lack. 

 The flowers of P. drymifolia are typically more pubescent, and 

 the under surfaces of the leaves more glaucous, than those of 

 P. americana. The fruits also are distinct, having a thin, 

 almost membranous skin in the former species, and a thick 

 leathery or brittle skin in the latter. The horticultural 

 differences are of more interest here than the botanical ; they 

 will be referred to later, in the discussion of the horticultural 

 races. 



Seedling avocados of both species vary in habit of growth, 

 being sometimes short and spreading, but more commonly erect, 

 even slender. On shallow soils they may not reach more 

 than 30 feet in height, while on deep moist clay-loams they 

 sometimes reach 60 feet. Budded trees are usually more 

 compact in habit than seedlings, and probably will not attain 

 such great ultimate dimensions. 



While the avocado is classed as an evergreen, trees of some 

 varieties cast their foliage at the time of flowering, the new 

 leaves making their appearance almost immediately. The 

 leaf-blades are multiform, some of the commonest shapes being 

 lanceolate, elliptic-lanceolate, elliptic, oblong-elliptic, oval, 

 ovate, and obovate. The apex differs from almost blunt to 

 acuminate, while the base is usually acute or truncate. The 

 length of the blades ranges between 3 or 4 inches and as much 

 as 16 inches. P. drymifolia usually has smaller leaves than 

 P. americana, both species exhibiting a wide diversity in leaf 

 form. 



In the United States the flowers appear from November to 



