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 Islands and Madagascar are known as caffein-free coffee trees. Just whether they are entitled to this classification or not is a question. Some of the French and German investigators have reported coffee from these regions that was absolutely devoid of caffein. It was thought at first that they must represent an entirely new genus; but upon investigation, it was found that they belonged to the genus _Coffea_, to which all our common coffees belong. Professor Dubard, of the French National Museum and Colonial Garden, studied these trees botanically and classified them as _C. Gallienii_, _C. Bonnieri_, _C. Mogeneti_, and _C. Augagneuri_. The beans of berries from these trees were analyzed by Professor Bertrand and pronounced caffein-free; but Labroy, in writing of the same coffee, states that, while the bean is caffein-free, it contains a very bitter substance, cafamarine, which makes the infusion unfit for use. Dr. O.W. Willcox[98], in examining some specimens of wild coffee from Madagascar, found that the bean was not caffein-free; and though the caffein content was low, it was no lower than in some of the Porto Rican varieties. Hartwich[99] reports that Hanausek found no caffein in _C. mauritiana_, _C. humboltiana_, _C. Gallienii_, _C. Bonnerii_, and _C. Mogeneti_. _Fungoid Disease of Coffee_ The coffee tree, like every other living thing, has specific diseases and enemies, the most common of which are certain fungoid diseases where the mycelium of the fungus grows into the tissue and spots the leaves, eventually causing them to fall, thus robbing the plant of its only means of elaborating food. Its most deadly enemy in the insect world is a small insect of the lepidopterous variety, which is known as the coffee-leaf miner. It is closely related to the clothes moth and, like the moth, bores in its larval stage, feeding on the mesophyl of the leaves. This gives the leaves an appearance of being shriveled or dried by heat.