26 2 
Journal of Agricultural Research 
Vol. VII, No. 6 
by horticulturists for a period of 5 to 15 years, and records as to compara¬ 
tive hardiness have been obtained. These records show that the horti¬ 
cultural types differ significantly in regard to the amount of frost to 
which they can be subjected without injury. 
The cultivated avocados fall naturally into three groups, or types, 
each of which possesses distinguishing characteristics which are quite 
constant, though occasional forms are seen which appear to be interme¬ 
diate or to belong to distinct groups not yet well known in cultivation. 
The characteristics of the three cultivated types are briefly as follows: 
Mexican Type. —Foliage and sometimes the fruit distinctly anise- 
scented. Leaves usually smaller than those of the Guatemalan and 
West Indian types. Fruit commonly 4 to 8 ounces in weight; skin 
thin, often membranous, usually smooth and glossy on the surface. 
Seed coats thin; closely united and adhering to the cotyledons, or 
separating, as in the West Indian type. Flowers heavily pubescent, 
appearing in early spring, from January to March in California and 
Florida. Ripe fruits from June to October. Occasionally a second 
crop, from later bloom, ripens in winter and spring. 
Guatemalan type. —Foliage not anise-scented, deep green, the new 
growth bronze-red, commonly, but not always, deeper colored than that 
of the West Indian type. Fruits commonly from 12 to 18 ounces in 
weight; skin usually verrucose or tuberculate on the surface, one-six¬ 
teenth to three-sixteenths of an inch thick, woody, brittle, and coarsely 
granular in texture, sharply differentiated from the flesh. Seed, as a 
rule, comparatively small; cotyledons smooth; the seed coats thin, 
closely united, and adhering to the cotyledons throughout. Flowers 
more finely pubescent than in the Mexican type, appearing in late 
spring—March to May in Florida. Fruits matured in the winter or 
spring of the following year. 1 
West Indian type. —Foliage not anise-scented; generally similar to 
the Guatemalan, but the young branchlets and leaves often lighter in 
color. Fruits variable in form and size, as in the other types, compara¬ 
tively large, averaging 14 to 20 ounces, but sometimes weighing 3 pounds 
or more; surface nearly always smooth, the skin rarely more than one- 
sixteenth of an inch thick, pliable and leathery, and scarcely so well 
differentiated from the flesh as in the Guatemalan. Seed usually large 
in proportion to the size of the fruit; cotyledons more or less rough; 
the two seed coats frequently thick and separated, at least over the 
distal end of the seed, one adhering to the cotyledons and the other loose 
or adhering to the wall of the seed cavity. Flowers usually as pubescent 
as those of the Guatemalan type, occasionally glabrate; in Florida and 
the West Indies they appear from February to April. Matured fruits 
from July to November. 
1 Some of the varieties of this type have the skin nearly smooth and about the same thickness as that of 
the West Indian. For this reason they have been considered by a few horticulturists as forming a distinct 
class; but inasmuch as they seem to differ only in these two points, which are both variable characters 
at best, it seems safe to retain them in the Guatemalan type. 
