The Twentieth Century


mated the value of the expanding date industry in 1928 at
$500,000. From these studies, more scientific information on
the date accumulated in the Southwest than in all the date
growing regions of the Old World combined.
 The acquisition by the United States of tropical island colonies
after the Spanish-American War provided climates suited to the
production of crops that had been suggested for Florida. Experi-
ment stations were set up in the colonies to determine what
varieties of coffee, cacao, bananas, avocadoes, fiber plants, and
rubber plants were most desirable, before introducing these
plants into the United States.
 Mangoes-After a tree of the East Indian mulgoba mango
survived a severe freeze in Florida in 1895, the Bureau of Plant
Industry sought other mangoes with resistance to frost. Fifty of
the best varieties from India also were procured in 1903 to
satisfy a mango enthusiasm among growers in the South. The
Department had the largest mango collection in the western
hemisphere in 1905 with more than a hundred varieties. Col-
lections were sent to Florida, Puerto Rico, and Hawaii for
fruiting trials. Fiberless East Indian mangoes had fruited in
Florida by 1909. Mangoes were looked upon as a coming crop
in the South and there was a great demand for grafted varieties.
Florida mangoes are now marketed to a limited extent at high
prices.
 Avocadoes-Hundreds of introductions of avocadoes were made
in early efforts to establish them in California and Florida. After
Guatemalan varieties introduced in 1914 had been propagated
for distribution, the plant's value became recognized. The most
important contribution to this crop was the collection of twenty-
three varieties sent from Guatemala by Wilson Popenoe in 1916.
After distribution of these, many avocadoes came into commer-
cial production. A search for cold-resistant varieties brought more
valuable plants from Ecuador and Mexico in 1922.
 The mangosteen, a tropical fruit promoted by Fairchild after
he had been attracted by it in the East Indies, failed to prosper
for lack of a good root system. To increase its chances of success,
a related plant was found in 1909 for use as a rootstock. Pine-
apple plants were secured in 1903 from Natal, South Africa, to
improve this established crop.
 Cassavas and dasheens were considered desirable for their
fleshy, edible rootstocks. P. H. Rolfs, an agent of the Depart-