MISSOURI BOTANICAL GARDEN BULLETIN 147 
AVOCADO (PERSEA GRATISSIMA) 
The avocado has been grown in Mexico for several cen- 
turies, as many as 2000 to 3000 fruits often being produced 
annually from a single tree. However, these are of the seed- 
ling type and of very little value commercially. The fruit 
varies with the variety, but generally it is about the shape and 
size of a pear and sometimes bears the misleading name of 
alligator pear. 
Within the last twenty years plant breeders of Florida 
and California have given systematic attention to the im- 
provement of the avocado. Previous to 1900 propagation was 
_ entirely through seed, which resulted in inferior fruit similar 
to that of the Mexican type. Since that date propagation has 
been effected by budding, using selected and varied varieties. 
One of the earliest orchards from budded stock was planted 
by Mr. S. B. Bliss, of Miami, Florida, and consists of twenty 
acres of the Trapp variety. The first marketable crop was 
shipped about 1910. A good yield of the type is between two 
to three hundred fruits annually for a medium-sized tree. 
The fruit of selected varieties varies from one to six inches 
in diameter and from several ounces to three or four pounds 
in weight. In shape it ranges from spherical to slender pyri- 
form. The skin is similar to that of the apple in thickness, 
is occasionally soft and pliable, and sometimes coarse granular 
and woody, suggesting a shell 1% inch thick. The fieshy inner 
portion is a mass of yellowish pulp of the consistency of but- 
ter and of a nutty flavor. The avocado is different from other 
fruits, due to its high percentage of vegetable oil, reaching 18 
per cent. It is therefore considered more as a food than a 
dessert. 
In commercial use the fruit is selected that has uniformity 
in shape, the round or oval type being easier to pack than the 
pear or bottle-shaped varieties. The ideal skin should be 
thick enough to withstand handling in packing and shipping. 
Flavor and quality are of course important factors. 
The largest plant in the economic house reaches the roof, 
being thirty feet in height. It is a representative of the seed- 
ling type. * 
CHAYOTE (CHAYOTA EDULIS) 
The chayote is a strong climbing plant or vine somewhat 
resembling the common cucumber in growth, although the 
vines are far more rampant. It is readily killed by frost but is. 
reported hardy as far north as South Carolina, provided the. 
