an gardens in 1919.

Among other allied _robusta_ species are:

_Ugandae_:, whose produce is said to possess a better flavor than
_robusta_;

_Bukobensis_, different from _Ugandae_ in the color of its berries, which
are a dark red; and

_Quillou_, having bright red fruit, a copper-colored silver skin, three
pounds of fruit producing one pound of market coffee. Some people prefer
_Quillou_ to _robusta_ because of the difference in the taste of the
roasted bean.

_Some Interesting Hybrids_

The most popular hybrid belongs to a crossing of _liberica_ and
_arabica_. Cramer states that the beans of this hybrid make an excellent
coffee combining the strong taste of the _liberica_ with the fine flavor
of the old Government Java _(arabica_), adding:

The hybrids are not only of value to the roaster, but also to the
planter. They are vigorous trees, practically free from leaf
disease; they stand drought well and also heavy rains; they are not
particular in regard to shade and upkeep; never fail to give a fair
and often a rather heavy crop. The fruit ripens all the year
around, and does not fall so easily as in the case of _arabica_.

Among other hybrids (many were still under trial in 1919) may be
mentioned: _Coffea excelsia x liberica_; _C. Abeokutae x liberica_; _C.
Dybowskii x excelsa_; _C. stenophylla x Abeokutae_; _C. congensis x
Ugandae_; _C. Ugandae x congensis_; and _C. robusta x Maragogipe_.

There are many species of _Coffea_ that stand quite apart from the main
groups, _arabica, robusta_ and _liberica_; but while some are of
commercial value, most of them are interesting only from the scientific
point of view. Among the latter may be mentioned: _Coffea bengalensis_,
_C. Perieri_, _C. mauritiana_, _C. macrocarpa_, _C. madagascariensis_,
and _C. schumanniana_.

[Illustration: COFFEA QUILLOU FLOWERS IN FULL BLOOM]

M. Teyssonnier, of the experimental garden at Camayenne, French Guinea,
West Africa, has produced a promising species of coffee known as
_affinis_. It is a hybrid of _C. stenophylla_ with a species of
_liberica_.

Among other promising species recognized by Dr. Cramer are:

_Coffea congensis_, whose berry resembles that of _C. arabica_, when
well prepared for the market being green or bluish; and

_Coffea congensis var. Chalotii_, probably a hybrid of _C. congensis_
with _C. canephora_.

_Caffein-free Coffee_

Certain trees growing wild in the Comoro Islan