IN the course of a few lectures it is naturally impossible to

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1 W. G. Freeman. 75 CURRENT INVESTIGATIONS IN ECONOMIC BOTANY. A COURSE OF LI-XTURES DELIVERED AT THE UNIVERSITY OF LONDON DURING THE MiCHAELMAS TERM, 1904, BY W. G. FREHMAN, A.R.C.S., B.Sc, F.L.S., Superintendent of Colonial Economic Collections, Imperial Institute. I. INTRODUCTORY. IN the course of a few lectures it is naturally impossible to deal with all, or even with the majority of most important of the problems engaging the attention of workers in the field of economic botany. Accordingly, selection has been made of those with which my duties in various parts of the world have brought me into contact, and are of interest as examples of current methods of economic botanical research. For these reasons attention is principally devoted in these lectures to four plants, the sugar-cane, the sugar-beet, cotton and maize. In this, the first lecture of a course on what is practically a new subject in the botanical curriculum of London University, it is desirable to consider what we understand by the term " economic botany." Economic botany comprises the study of the plants and plant products, which directly or indirectly are of service to man, including their source, distribution, improvement, collection and preparation, their properties and uses. Economic botany is one of the oldest, if not the oldest, study of mankind. Go where we will in the world, even amongst the lowest races of mankind, we find considerable knowledge of the wild plants of the country, and their properties and uses. On plants, primitive, in common with highly-civilized races, are ultimately dependent, to a greater or less extent, for their food, medicine and clothing. As an advance on the mere possession of knowledge of the properties and uses of indigenous plants, one often finds amongst savage races, successful cultivation of certain plants. This, in its turn, leads to practical efforts to improve plants by means of vegetative or seminal selection, which in the remote past have resulted in far-reaching results, dealt with in detail later. It should not be assumed that in the successful practice of the past the reason for each step was necessarily understood. The knowledge accumulated was purely empirical, yet it was attained by exactly the same method as much knowledge

2 76 W. G. Freeman. is attained to-day, namely, by experiment, observation and inference. That the so-called savage does deliberately apply this method, was brought to my notice in a striking manner, only a few months ago, in an uncivilized portion of West Africa, where I found that localities for native " farms " were selected by the experimental planting of a few yams or a small patch of Indian corn, and I frequently saw in the " bush " little cultivated patches, often only a few yards square, which were evidently native experiment plots. The study of systematic botany can be traced back to the search after plants for their economic uses. Sachs points out in the opening lines of his History of Botany, how " the authors of the oldest herbals of the 16th century regarded plants mainly as the vehicles of medicinal virtues: to them plants were the ingredients of compound medicines, and were therefore by preference named siniplicia." He describes how the labours of the flrst German composers of herbals who went straight to nature, described the wild plants growing around them, and had figures of laitm carefully executed in wood resulted in the flrst beginning of a really scientific examination of plants. " In the effort to promote the knowledge of plants for practical purposes the impression forced itself on the mind of the observer that there are various natural groups of plants which have a distinct resemblance to one another, in form and other general characteristics." Practice was in advance of exact knowledge in the appreciation of the beneficial action of leguminous plants. Again, the vexed question of the use of shade trees in tropical agriculture has had considerable light thrown upon it by the recent generalization that the time-honoured shade trees, with few exceptions, are members of the LegHininosue. In some cases the shade was no doubt directly beneficial, in other cases harmful, but in the latter the net result might still be beneficial owing to the counterbalancing action of the trees in increasing the fertility of the soil. The important results obtained in the remote past, have already been alluded to. For a comprehensive account, the classical work of De CandoUe On the Origin of Cultivated Plants should be consulted. In the following table an attempt has been made to indicate, at a glance, the duration of time through which some of the more economic plants have been cultivated : Cultivated for more than 2000 years. CEREALS. Wheat. Barley. Oats. Millet. Sorghum. Rice.l'Maize,

3 Current Investigations in Economic Botany. yj Cultivated for more than 2000 years. Cultivated for less than 2000 years. STARCH PLANTS. Potato. Sweet Potato {Ipomcea Batatas) Yams (Dioscorea spp.j. Cassava {Manihot utilissima). Colocasia antiquoruui. Bread Fruit {Artocarpus {incisa). LEGUMES. FRUITS. Garden Pea {Pisnin sativum). Bean. Lentil. Ground Nut {Arachis Jiypogea). Banana. Fig. Apple. SUGAR PLANTS. Sugar cane. DYE PLANTS. Date. Vine. Plum. Indigo. Madder. Henna {Lawsonia alba) Saffron. MEDICINAL PLANTS, ETC. Hemp. Coca. RUBBER PLANTS, ETC. FODDER PLANTS. Tobacco. Tea. FIBRE PLANTS. Flax {Linum usitatissimum). Hemp {Cannabis sativa). Cotton [Gossypimn spp.). Field Pea {Pisum arvense). Pigeon Pea.{CajiinHs indicus). Orange. Strawberry. Gooseberry. Sugar-beet. Coffee. Cinchona. Raspberry. Melon. Currants. Ceara Rubber {Manihot Glaziovii). Para Rubber {Hevea braziliensis). Central American Rubber {Castilloa elastica). Lagos Silk Rubber {Funtu)nia elastica). Asam Kuhher {Ficus elastica). Gutta Percha Tree {Dicliopsis Gutta.) The Hay Grasses of temperate climates and species of Trifolium and Medicago Guinea Grass (Paiiicnm luaxiiinim). Sour Grass, West Indies, {Andropogon pertnsus), etc. Sisal Hemp {Agave rigida var. sisalana.) New Zealand Hemp {Phormium Tenax). This table might be considerably extended, but as it stands it suffices to demonstrate that all the principal cultivated food plants

4 78 Current Investigations in Economic Botany. the cereals, farinaceous plants, legumes and fruits and also several of the more important plants yielding fibres, dyes, and narcotics are plants of ancient cultivation. Amongst the plants of recent cultivation only, we find some pleasant fruits of minor dietetic value, some medicinal plants, but practically all the fodder and rubber-yielding plants, and others whose products have come into demand owing to changes in the conditions of life of the human races, and progress in the arts and sciences. As De Candolle well says, " Men have not discovered and cultivated within the last two thousand years a single species which can rival maize, rice, the sweet potato, the potato, the bread fruit, the date, cereals, millets, sorghum, the banana, soy. These date from three, four, or five thousand years, perhaps even in some cases six thousand years. The species first cultivated during the Graeco-Roman civilization and later nearly all answer to these varied or more refined needs We must come to the middle of the present [Nineteenth] Century to find new cultivations of any value from the utilitarian point of view, such as Eucalyptus globulus of Australia and the Cinchonas of South America." Reviewing the subject in the Twentieth Century, we can add the rubber plants as noteworthy examples of new, cultivated plants. It would appear that at a very early stage in the history of agriculture in different parts of the world, the plants of the greatest value to man (for instance for food), were recognised and cultivated, and no plants of equal primary value having since been found, the early selected plants have been improved by cultivation and distributed from land to land to the exclusion of others. Within recent years a similar sequence of events has resulted in certain plants, for instance a few species of Cinchona and certain rubber-yielding plants being cultivated to the exclusion of others of less importance. Owing to reckless extermination by man one such plant, at any rate, Dichopsis Gutta, has already passed practically into the group of economic plants only known in cultivation. The history of other economic plants may have been similar, and it is possible tliat plants now only known in cultivation were once wild species, and have been exterminated owing to various causes. On the other hand some, no doubt, have been so changed by selection through long ages that they have attained separate specific rank, and are not known out of cultivation, whilst their ancestral types may still survive and be regarded closely related wild species. (To be eontinued.j

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