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Table of Contents

Its complete classification by class, sub-class, order, family, genus, and species—How the Coffea arabica grows, flowers, and bears—Other species and hybrids described—Natural caffein-free coffee—Fungoid diseases of coffee

The coffee tree, scientifically known as Coffea arabica, is native to Abyssinia and Ethiopia, but grows well in Java, Sumatra, and other islands of the Dutch East Indies; in India, Arabia, equatorial Africa, the islands of the Pacific, in Mexico, Central and South America, and the West Indies. The plant belongs to the large sub-kingdom of plants known scientifically as the Angiosperms, or Angiospermæ, which means that the plant reproduces by seeds which are enclosed in a box-like compartment, known as the ovary, at the base of the flower. The word Angiosperm is derived from two Greek words, sperma, a seed, and aggeion, pronounced angeion, a box, the box referred to being the ovary.

This large sub-kingdom is subdivided into two classes. The basis for this division is the number of leaves in the little plant which develops from the seed. The coffee plant, as it develops from the seed, has two little leaves, and therefore belongs to the class Dicotyledoneæ. This word dicotyledoneæ is made up of the two Greek words, di(s), two, and kotyledon, cavity or socket. It is not necessary to see the young plant that develops from the seed in order to know that it had two seed leaves; because the mature plant always shows certain characteristics that accompany this condition of the seed.

In every plant having two seed leaves, the mature leaves are netted-veined, which is a condition easily recognized even by the layman; also the parts of the flowers are in circles containing two or five parts, but never in threes or sixes. The stems of plants of this class always increase in thickness by means of a layer of cells known as a cambium, which is a tissue that continues to divide throughout its whole existence. The fact that this cambium divides as long as it lives, gives rise to a peculiar appearance in woody stems by which we can, on looking at the stem of a tree of this type when it has been sawed across, tell the age of the tree.

In the spring the cambium produces large open cells through which large quantities of sap can run; in the fall it produces very thick-walled cells, as there is not so much sap to be carried. Because these thin-walled open cells of one spring are next to the thick-walled cells of the last autumn, it is very easy to distinguish one year's growth from the next; the marks so produced are called annual rings.

We have now classified coffee as far as the class; and so far we could go if we had only the leaves and stem of the coffee plant. In order to proceed farther, we must have the flowers of the plant, as botanical classification goes from this point on the basis of the flowers. The class Dicotyledoneæ is separated into sub-classes according to whether the flower's corolla (the showy part of the flower which ordinarily gives it its color) is all in one piece, or is divided into a number of parts. The coffee flower is arranged with its corolla all in one piece, forming a tube-shaped arrangement, and accordingly the coffee plant belongs to the sub-class Sympetalæ, or Metachlamydeæ, which means that its petals are united.

The Coffee Tree, Showing Details of Flowers and Fruit

From a drawing by Ch. Emonts in Jardin's Le Caféier et Le Café

The next step in classification is to place the plant in the proper division under the sub-class, which is the order. Plants are separated into orders according to their varied characteristics. The coffee plant belongs to an order known as Rubiales. These orders are again divided into families. Coffee is placed in the family Rubiaceæ, or Madder Family, in which we find herbs, shrubs or trees, represented by a few American plants, such as bluets, or Quaker ladies, small blue spring flowers, common to open meadows in northern United States; and partridge berries (Mitchella repens).

The Madder Family has more foreign representatives than native genera, among which are Coffea, Cinchona, and Ipecacuanha (Uragoga), all of which are of economic importance. The members of this family are noted for their action on the nervous system. Coffee, as is well known, contains an active principle known as caffein which acts as a stimulant to the nervous system and in small quantities is very beneficial. Cinchona supplies us with quinine, while Ipecacuanha produces ipecac, which is an emetic and purgative.

The families are divided into smaller sections known as genera, and to the genus Coffea belongs the coffee plant. Under this genus Coffea are several sub-genera, and to the sub-genus Eucoffea belongs our common coffee, Coffea arabica. Coffea arabica is the original or common Java coffee of commerce. The term "common" coffee may seem unnecessary, but there are many other species of coffee besides arabica. These species have not been described very frequently; because their native haunts are the tropics, and the tropics do not always offer favorable conditions for the study of their plants.

All botanists do not agree in their classification of the species and varieties of the coffea genus. M.E. de Wildman, curator of the royal botanical gardens at Brussels, in his Les Plantes Tropicales de Grande Culture, says the systematic division of this interesting genus is far from finished; in fact, it may be said hardly to be begun.

Coffea arabica we know best because of the important rôle it plays in commerce.

Complete Classification of Coffee
Kingdom	Vegetable
Sub-Kingdom	Angiospermæ
Class	Dicotyledoneæ
Sub-class	Sympetalæ or Metachlamydeæ
Order	Rubiales
Family	Rubiaceæ
Genus	Coffea
Sub-genus	Eucoffea
Species	C. arabica

The coffee plant most cultivated for its berries is, as already stated, Coffea arabica, which is found in tropical regions, although it can grow in temperate climates. Unlike most plants that grow best in the tropics, it can stand low temperatures. It requires shade when it grows in hot, low-lying districts; but when it grows on elevated land, it thrives without such protection. Freeman[94] says there are about eight recognized species of coffea.

Details of the Germination of the Coffee Plant

From a drawing by Ch. Emonts in Jardin's Le Caféier et Le Café

Coffea Arabica

Coffea arabica is a shrub with evergreen leaves, and reaches a height of fourteen to twenty feet when fully grown. The shrub produces dimorphic branches, i.e., branches of two forms, known as uprights and laterals. When young, the plants have a main stem, the upright, which, however, eventually sends out side shoots, the laterals. The laterals may send out other laterals, known as secondary laterals; but no lateral can ever produce an upright. The laterals are produced in pairs and are opposite, the pairs being borne in whorls around the stem. The laterals are produced only while the joint of the upright, to which they are attached, is young; and if they are broken off at that point, the upright has no power to reproduce them. The upright can produce new uprights also; but if an upright is cut off, the laterals at that position tend to thicken up. This is very desirable, as the laterals produce the flowers, which seldom appear on the uprights. This fact is utilized in pruning the coffee tree, the uprights being cut back, the laterals then becoming more productive. Planters generally keep their trees pruned down to about six feet.

The leaves are lanceolate, or lance-shaped, being borne in pairs opposite each other. They are three to six inches in length, with an acuminate apex, somewhat attenuate at the base, with very short petioles which are united with the short interpetiolar stipules at the base. The coffee leaves are thin, but of firm texture, slightly coriaceous. They are very dark green on the upper surface, but much lighter underneath. The margin of the leaf is entire and wavy. In some tropical countries the natives brew a coffee tea from the leaves of the coffee tree.

BRAZIL COFFEE PLANTATION IN FLOWER

The coffee flowers are small, white, and very fragrant, having a delicate characteristic odor. They are borne in the axils of the leaves in clusters, and several crops are produced in one season, depending on the conditions of heat and moisture that prevail in the particular season. The different blossomings are classed as main blossoming and smaller blossomings. In semi-dry high districts, as in Costa Rica or Guatemala, there is one blossoming season, about March, and flowers and fruit are not found together, as a rule, on the trees. But in lowland plantations where rain is perennial, blooming and fruiting continue practically all the year; and ripe fruits, green fruits, open flowers, and flower buds are to be found at the same time on the same branchlet, not mixed together, but in the order indicated.

Coffea Arabica—Porto Rico

The flowers are also tubular, the tube of the corolla dividing into five white segments. Dr. P.J.S. Cramer, chief of the division of plant breeding, Department of Agriculture, Netherlands India, says the number of petals is not at all constant, not even for flowers of the same tree. The corolla segments are about one-half inch in length, while the tube itself is about three-eighths of an inch long. The anthers of the stamens, which are five in number, protrude from the top of the corolla tube, together with the top of the two-cleft pistil. The calyx, which is so small as to escape notice unless one is aware of its existence, is annular, with small, tooth-like indentations.

While the usual color of the coffee flower is white, the fresh stamens and pistils may have a greenish tinge, and in some cultivated species the corolla is pale pink.

The size and condition of the flowers are entirely dependent on the weather. The flowers are sometimes very small, very fragrant, and very numerous; while at other times, when the weather is not hot and dry, they are very large, but not so numerous. Both sets of flowers mentioned above "set fruit," as it is called; but at times, especially in a very dry season, they bear flowers that are few in number, small, and imperfectly formed, the petals frequently being green instead of white. These flowers do not set fruit. The flowers that open on a dry sunny day show a greater yield of fruit than those that open on a wet day, as the first mentioned have a better chance of being pollinated by the insects and the wind. The beauty of a coffee estate in flower is of a very fleeting character. One day it is a snowy expanse of fragrant white blossoms for miles and miles, as far as the eye can see, and two days later it reminds one of the lines from Villon's Des Dames du Temps Jadis.

Where are the snows of yesterday?

The winter winds have blown them all away.

Coffea Arabica, Flower and Fruit—Costa Rica

But here, the winter winds are not to blame: the soft, gentle breezes of the perpetual summer have wrought the havoc, leaving, however, a not unpleasing picture of dark, cool, mossy green foliage.

The flowers are beautiful, but the eye of the planter sees in them not alone beauty and fragrance. He looks far beyond, and in his mind's eye he sees bags and bags of green coffee, representing to him the goal and reward of all his toil. After the flowers droop, there appear what are commercially known as the coffee berries. Botanically speaking, "berry" is a misnomer. These little fruits are not berries, such as are well represented by the grape; but are drupes, which are better exemplified by the cherry and the peach. In the course of six or seven months, these coffee drupes develop into little red balls about the size of an ordinary cherry; but, instead of being round, they are somewhat ellipsoidal, having at the outer end a small umbilicus. The drupe of the coffee usually has two locules, each containing a little "stone" (the seed and its parchment covering) from which the coffee bean (seed) is obtained. Some few drupes contain three, while others, at the outer ends of the branches, contain only one round bean, known as the peaberry. The number of pickings corresponds to the different blossomings in the same season; and one tree of the species arabica may yield from one to twelve pounds a year.

Young Coffea Arabica Tree at Kona, Hawaii

In countries like India and Africa, the birds and monkeys eat the ripe coffee berries. The so-called "monkey coffee" of India, according to Arnold, is the undigested coffee beans passed through the alimentary canal of the animal.

Survivors of the First Liberian Coffee Trees Introduced into Java in 1876

The pulp surrounding the coffee beans is at present of no commercial importance. Although efforts have been made at various times by natives to use it as a food, its flavor has not gained any great popularity, and the birds are permitted a monopoly of the pulp as a food. From the human standpoint the pulp, or sarcocarp, as it is scientifically called, is rather an annoyance, as it must be removed in order to procure the beans. This is done in one of two ways. The first is known as the dry method, in which the entire fruit is allowed to dry, and is then cracked open. The second way is called the wet method; the sarcocarp is removed by machine, and two wet, slimy seed packets are obtained. These packets, which look for all the world like seeds, are allowed to dry in such a way that fermentation takes place. This rids them of all the slime; and, after they are thoroughly dry, the endocarp, the so-called parchment covering, is easily cracked open and removed. At the same time that the parchment is removed, a thin silvery membrane, the silver skin, beneath the parchment, comes off, too. There are always small fragments of this silver skin to be found in the groove of the coffee bean contained within the parchment packet.

COFFEA ARABICA IN FLOWER ON A JAVA ESTATE

From a photograph made at Dramaga, Preanger, Java, in 1907

Liberian Coffee Tree at Lamoa, P.I.

We have said that the coffee tree yields from one to twelve pounds a year, but of course this varies with the individual tree and also with the region. In some countries the whole year's yield is less than 200 pounds per acre, while there is on record a patch in Brazil which yields about seventeen pounds to the tree, bringing the yield per acre much higher.

The beans do not retain their vitality for planting for any considerable length of time; and, if they are thoroughly dried, or are kept for longer than three or four months, they are useless for that purpose. It takes the seed about six weeks to germinate and to appear above ground. Trees raised from seed begin to blossom in about three years; but a good crop can not be expected of them for the first five or six years. Their usefulness, save in exceptional cases, is ended in about thirty years.

The coffee tree can be propagated in a way other than by seeds. The upright branches can be used as slips, which, after taking root, will produce seed-bearing laterals. The laterals themselves can not be used as slips. In Central America the natives sometimes use coffee uprights for fences and it is no uncommon sight to see the fence posts "growing."

The wood of the coffee tree is used also for cabinet work, as it is much stronger than many of the native woods, weighing about forty-three pounds to the cubic foot, having a crushing strength of 5,800 pounds per square inch, and a breaking strength of 10,900 pounds per square inch.

The propagation of the coffee plant by cutting has two distinct advantages over propagation by seed, in that it spares the expense of seed production, which is enormous, and it gives also a method of hybridization, which, if used, might lead not only to very interesting but also to very profitable results.

Two-and-One-Half-Year-Old C. Congensis

The hybridization of the coffee plant was taken up in a thoroughly scientific manner by the Dutch government at the experimental garden established at Bangelan, Java, in 1900. In his studies, twelve varieties of Coffea arabica are recognized by Dr. P.J.S. Cramer[95], namely:

Laurina, a hybrid of Coffea arabica with C. mauritiana, having small narrow leaves, stiff, dense branches, young leaves almost white, berry long and narrow, and beans narrow and oblong.

Murta, having small leaves, dense branches, beans as in the typical Coffea arabica, and the plant able to stand bitter cold.

Menosperma, a distinct type, with narrow leaves and bent-down branches resembling a willow, the berries seldom containing more than one seed.

A HEAVY FLOWERING OF FIVE-YEAR-OLD COFFEA EXCELSA

This is a comparatively new species, discovered in the Tchad Lake district of West Africa in 1905. It is a small-beaned variety of Coffea liberica

Branches of Coffea Excelsa Grown at the Lamao Experiment Station, P.I.

Mokka (Coffea Mokkæ), having small leaves, dense foliage, small round berries, small round beans resembling split peas, and possessed of a stronger flavor than Coffea arabica.

Purpurescens, a red-leaved variety, comparable with the red-leaved hazel and copper beech, a little less productive than the Coffea arabica.

Variegata, having variegated leaves striped and spotted with white.

Amarella, having yellow berries, comparable with the white-fruited variety of the strawberry, raspberry, etc.

Bullata, having broad, curled leaves; stiff, thick, fragile branches, and round, fleshy berries containing a high percentage of empty beans.

Angustifolia, a narrow-leaved variety, with berries somewhat more oblong and, like the foregoing, a poor producer.

Erecta, a variety that is sturdier than the typical arabica, better suited to windy places, and having a production as in the common arabica.

Maragogipe, a well-defined variety with light green leaves having colored edges: berries large, broad, sometimes narrower in the middle; a light bearer, the whole crop sometimes being reduced to a couple of berries per tree.[96]

C. Stenophylla, From Which Is Obtained the Highland Coffee of Sierra Leone

Columnaris, a vigorous variety, sometimes reaching a height of 25 feet, having leaves rounded at the base and rather broad, but a shy bearer, recommended for dry climates.

Coffea Stenophylla

Coffea arabica has a formidable rival in the species stenophylla. The flavor of this variety is pronounced by some as surpassing that of arabica. The great disadvantage of this plant is the fact that it requires so long a time before a yield of any value can be secured. Although the time required for the maturing of the crop is so long, when once the plantation begins to yield, the crop is as large as that of Coffea arabica, and occasionally somewhat larger. The leaves are smaller than any of the species described, and the flowers bear their parts in numbers varying from six to nine. The tree is a native of Sierra Leone, where it grows wild.

Copyright, 1909, by The Tea and Coffee Trade Journal

NEAR VIEW OF COFFEE BERRIES OF COFFEA ARABICA

Coffea Liberica

The bean of Coffea arabica, although the principal bean used in commerce, is not the only one; and it may not be out of place here to describe briefly some of the other varieties that are produced commercially. Coffea liberica is one of these plants. The quality of the beverage made from its berries is inferior to that of Coffea arabica, but the plant itself offers distinct advantages in its hardy growing qualities. This makes it attractive for hybridization.

Wild "Caffein-Free" Coffee Tree

Mantsaka or Café Sauvage—Madagascar

The Coffea liberica tree is much larger and sturdier than the Coffea arabica, and in its native haunts it reaches a height of 30 feet. It will grow in a much more torrid climate and can stand exposure to strong sunlight. The leaves are about twice as long as those of arabica, being six to twelve inches in length, and are very thick, tough, and leathery. The apex of the leaf is acute. The flowers are larger than those of arabica, and are borne in dense clusters. At any time during the season, the same tree may bear flowers, white or pinkish, and fragrant, or even green, together with fruits, some green, some ripe and of a brilliant red. The corolla has been known to have seven segments, though as a rule it has five. The fruits are large, round, and dull red; the pulps are not juicy, and are somewhat bitter. Unlike Coffea arabica, the ripened drupes do not fall from the trees, and so the picking can be delayed at the planter's convenience.

Differentiating Characteristics of Coffee Beans, in Cross-section

Col. I. Mature bean. Col. II. Embryo.

A. Coffea arabica, R. Coffea robusta, L. Coffea liberica

Among the allied Liberian species Dr. Cramer recognizes:

Abeokutæ, having small leaves of a bright green, flower buds often pink just before opening (in Liberian coffee never), fruit smaller with sharply striped red and yellow shiny skin, and producing somewhat smaller beans than Liberian coffee, but beans whose flavor and taste are praised by brokers;

Dewevrei, having curled edged leaves, stiff branches, thick-skinned berries, sometimes pink flowers, beans generally smaller than in C. liberica, but of little interest to the trade;

Arnoldiana, a species near to Coffea Abeokutæ having darker foliage and the even colored small berries;

Laurentii Gillet, a species not to be confused with the C. Laurentii belonging to the robusta coffee, but standing near to C. liberica, characterized by oblong rather than thin-skinned berries;

Excelsa, a vigorous, disease-resisting species discovered in 1905 by Aug. Chevalier in West Africa, in the region of the Chari River, not far from Lake Tchad. The broad, dark-green leaves have an under side of light green with a bluish tinge; the flowers are large and white, borne in axillary clusters of one to five; the berries are short and broad, in color crimson, the bean smaller than robusta, very like Mocha, but in color a bright yellow like liberica. The caffein content of the coffee is high, and the aroma is very pronounced;

Dybowskii, another disease-resisting variety similar to excelsa, but having different leaf and fruit characteristics;

Lamboray, having bent gutter-like leaves, and soft-skinned, oblong fruit;

Wanni Rukula, having large leaves, a vigorous growth, and small berries;

Coffea aruwimensis, being a mixture of different types.