14 MANUAL OF TROPICAL AND SUBTROPICAL FRUITS 



and slender, almost the shape of a cucumber, at the other. 

 The color varies from yellow-green or almost yellow through 

 many shades of green to crimson, maroon, brown, purple, and 

 almost black. The skin is as thin as that of an apple in many 

 varieties of P. drymifolia; in P. americana it is occasionally a 

 quarter of an inch thick, and hard and woody in texture. The 

 fleshy edible part which lies between the skin and the seed is of 

 buttery consistency, yellow or greenish yellow in color, of a 

 peculiarly rich nutty flavor in the best varieties, and contains a 

 high percentage of oil. The flesh is traversed from the stem 

 to the base of the seed by streaks or fine fibers (invisible in the 

 ripe fruit of many varieties) which represent the vascular 

 system. The single large seed is oblate, spherical, conical, or 

 slender, inverted so that the young shoot develops from the 

 end which lies toward the stem of the fruit. It is covered by 

 two seed-coats, varying in thickness, often adhering closely to 

 one another. The cotyledons are normally two, occasionally 

 three in P. drymifolia, white or greenish white in color, smooth 

 or roughened on the surface. 



HISTORY AND DISTRIBUTION 



The native home of the avocado is on the mainland of tropical 

 America. Per sea drymifolia is abundant in the wild state on 

 the lower slopes of the volcano Orizaba, in southern Mexico, 

 as well as in other parts of that country. The extent of its 

 distribution is not precisely known. The native home of P. 

 americana has not been determined with certainty, since the 

 tree has been so long in cultivation and few efforts have as 

 yet been made to locate the region in which it is truly in- 

 digenous. 



Jacques Huber, in the Boletim do Museu Goeldi, says : 

 " Everything indicates that the avocado, originally indigenous 

 to Mexico, has been cultivated since immemorial times, and 



