This zone has a mean temperature of 78½ to 82½ Fahrenheit.

2. The tropical zone reaches from the 15th deg. on each side of the
equator to the tropics in 23 lat. The mean temperature is 73½ to 78¾
deg. Summer temperature 80½ to 86 deg.; winter temperature in the
eastern coast districts, 59 deg.

In this region is comprised the following countries:--Sandwich Isles,
Canton, in province of China, Burmah, Calcutta, and a portion of the
Bengal Presidency, the Bombay Presidency, Madagascar, Mauritius and
Bourbon; the southern portion of Brazil, Cuba, St. Domingo, Mexico,
and Central America.

3. The sub-tropical zone extends from the tropics 23 to 34 deg. of
latitude. There are a number of tropical fruits in this region. The
winters are mild and vegetation is green throughout the year. In the
northern division of the zone palms and bananas grow on the plains. In
this region is comprised all the extreme northern portions of Africa,
coasting the Mediterranean, comprising Algiers and the Barbary States,
Egypt, part of Persia, Cabool and the Punjab; the greater portion of
China, Lower California, Texas, the South-Western States of America,
the Bermudas, the Cape Colony and Natal, New South Wales, Southern and
Western Australia--the Government settlements in the Northern Island
of New Zealand, the largest portion of Chile, Paraguay, Uruguay and
the Argentine Republics, the Provinces of Brazil from St. Paul to Rio
Grande, Madeira and the Canary Isles.

To define accurately the conditions of temperature which a plant
requires to maintain it in a flourishing condition we must ascertain
within what limits its period of vegetation, may vary, and what