10 BULLETIN 743, TJ. S, DEPARTMENT OF AGRICULTURE. 
in all of the races, it tends at the same time to conceal many of their 
distinguishing characteristics. 
The term " race," which is here applied to the groups of varieties 
known in cultivation, seems more appropriate than the term " type," 
which is commonly used. The word " type " in this connection means 
nothing ; the word " race," on the other hand, has a definite horticul- 
tural meaning which seems to be applicable here. A race is a group of 
seedlings which possess certain well-defined characteristics in com- 
mon and will transmit these characteristics to their seedling progeny. 
This applies to the avocados under consideration, for each race has 
certain characteristics which never fail to be inherited by its seedlings. 
The three cultivated races may be distinguished by the following 
characters : 
Guatemalan race. — The foliage of the Guatemalan race is not anise scented ; 
hence, is easily distinguished from the Mexican. It is usually deep green in color, 
a somewhat deeper green than that of the West Indian. The flowers are not 
so heavily pubescent as those of the Mexican. The fruit varies greatly in form 
and size, but always has a woody outer covering one-sixteenth to one-fourth, of 
an inch thick. In some of the cultivated forms the skin or outer covering is 
scarcely thicker than in the West Indian race, but it is rarely so soft and pli- 
able. The seed is comparatively smooth, and the two thin closely united seed 
coats adhere closely to it. The seed is very rarely loose in the cavity within 
the fruit. 
West Indian race. — In the West Indian race the foliage is slightly lighter in 
color than in the Guatemalan, but, like the latter, devoid of the anise scent. 
The flowers are sometimes less pubescent than those of the Guatemalan, never 
more so, and always less pubescent than in the Mexican race. The fruits are 
variable in form and size, but the outer covering is soft and pliable and is 
rarely more than one-sixteenth of an inch thick. The seed is often rough, and 
the two seed coats frequently are thick and separated, at least over the distal 
end of the seed, one adhering to the cotyledons and the other being loose or 
adhering to the lining of the seed cavity. 
Mexican race. — The foliage and sometimes the fruit of the Mexican race are 
distinctly anise scented, and both are usually smaller than in the Guatemalan 
and West Indian races. The flowers are more heavily pubescent than in either 
of the latter. Its fruits have a very thin, often membranous skin. The seed is 
commonly smooth; the seed coats are thin, either closely united and adhering 
to the cotyledons (occasionally three in number), as in the Guatemalan race, 
or separating, as in the West Indian. 
AVOCADO CULTURE IN THE GUATEMALAN HIGHLANDS. 
In reading the statements which follow it must be kept in mind that 
the Guatemalan race of avocados is being considered. None other is 
grown to any extent in the highlands, the Mexican race rarely oc- 
curring in Guatemala and the West Indian being confined to the 
lowlands. Separate paragraphs will be devoted to these two races 
farther on. 
