October i, 1891] 



NATURE 



531 



deals with certain industrial, commercial, and economic ques- 

 tions : nevertheless it lies wholly within the domain of botany. 

 I invite you to examine with me some of the possibilities of 

 economic botany. 



Of course, when treating a topic which is so largely specula- 

 tive as this, it is difficult and unwise to draw a hard and fast 

 line between possibilities and probabilities. Nowadays possi- 

 bilities are so often realized rapidly that they become accom- 

 plished facts before we are aware. 



In asking what are the possibilities that other plants than 

 those we now use may be utilized we enter upon a many-sided 

 inquiry. Speculation is rife as to the coming man. May we not 

 ask what plants the coming man will use? 



Thtre is an enormous disproportion between the total number 

 of species of plants known to botanical science and the number 

 of those which are employed by man. 



The species of flowering plants already described and named 

 are about one hundred and seven thousand. Acquisitions from 

 unexplored or imperfectly explored regions may increase the 

 aggregate perhaps one-tenth, so that we are within very safe 

 limits in taking the number of existing species to be somewhat 

 above one hundred and ten thousand. 



No\y if we should make a comprehensive list ol all the 

 flowering plants which are cultivated on what we may call a 

 fairly large scale at the present day, placing therein all food and 

 forage plants, all those which are grown for timber and cabinet 

 woods, for fibres and cordage, for tanning materials, dyes, 

 resins, rubber, gums, oils, perfumes, and medicines, we could 

 bring together barely three hundred specie^. If we should add 

 to this short catalogue all the species, which, without cultivation, 

 can be used by man, we should find it considerably lengthened. 

 A great many products of the classes just referred to are derived 

 in commerce from wild plants, but exactly how much their 

 addition would extend the list, it is impossible in the present 

 state of knowledge to determine. Every enumeration of this 

 character is l.kely to contain errors from two sources: first, it 

 would be sure to cont.-iin some species which have outlived their 

 real usefulness ; and, secondly, owing to the chaotic condition of 

 the literature of the subject, omissions would occur. 



But after all proper exclusions and additions have been made, 

 the total number of species of flowering plants utilized to any 

 considerable extent by man in his civilized state does not exceed, 

 in fact it does not quite reach, one per cent. 



The disproportion between the plants which are known and 

 those which are used becomes much greater when we take into 

 account the species of flowerless plants also. Of the five hundred 

 ferns and their allies we employ for other than decorative pur- 

 poses only five ; the mosses and liverworts, roughly estimated at 

 five hundred species, have only four which are directly used by 

 man. There are comparatively few Algae, Fungi, or Lichens 

 which have extended use. 



Therefore, when we take the flowering and flowerless together, 

 the percentage of utilized plants falls far below the estimate 

 made for the flowering alone. 



Such a ratio between the number of species known and the 

 number used justifies the inquiry which I have proposed for dis- 

 cussion at this time— namely, can the short list of useful plants 

 be increased to advantage ? If so, how ? 



This is a practical question ; it is likewise a very old one. In 

 one form or another, by one people or another, it has been 

 asked from early limes. In the dawn of civilization, mankind 

 inherited from savage ancestors certain plants, which had been 

 found amenable to simple cultivation and the products of these 

 plants supplemented the spoils of the chase and of the sea. The 

 <|uestion which we ask now was asked then. Wild plants were 

 examined for new uses ; primitive agriculture and horticulture 

 extended their hounds in an-werto this inquiry. Age after age 

 has added slowly and cautiously to ihe list of cultivable and 

 utilizable plants, but the aggregate additions have been, as we 

 have seen, comparatively slight. 



The question has thus no charm of novelty, but it is as prac- 

 tical to-day as in early ages. In fact, at the present time, in 

 view of all the appliances at the command of modern science 

 and under the strong light cast by recent biological and techno- 

 logical research, the inquiry which we propose assumes great 

 importance. One phase of it is being attentively and sys- 

 tematically regarded in the great experiment stations, another 

 phase is being studied in the laboratories of chemistry and 

 pharmacy, while still another presents itself in the museums of 

 economic botany. 



NO. 1144, VOL. 44] 



Our question may be put in other words, which are even more 

 practical. What present likelihood is there that our tables may, 

 one of these days, have other vegetables, fruits, and cereals, 

 than those which we use now ? What chance is there that new 

 fibres may supplement or even replace those which we spin and 

 weave, that woven fabrics may take on new vegetable colours, 

 that flowers and leaves may yield new perfumes and flavours ? 

 What probability is there that new remedial agents may be 

 found among plants neglected or now wholly unknown ? The 

 answer which I shall attempt is not in the nature of a prophecy ; 

 it can claim no rank higher than that of a reasonable conjecture. 



At the outset it must be said that synthetic chemistry has 

 made and is making some exceedingly short cuts across this field 

 of research, giving us artificial dyes, odours, flavours, and 

 medicinal substances, of such excellence that it sometimes seems 

 as if before long the old-fashioned chemical processes in the 

 plant itself would play only a subordinate fart. But although 

 there is no telling where the triumphs of chemical synthesis will 

 end, it is not probable that it will ever interfere essentially 

 with certain classes of economic plants. It is impossible to 

 conceive of a synthetic fibre or a synthetic fruit. Chemistry 

 gives us fruit-ethers and fruit-acids, and after a while may pro- 

 vide us with a true artificial sugar and amorphous starch ; but 

 artificial fruits worth the eating or artificial fibres worth the 

 spinning are not coming in our day. 



Despite the extraordinary achievements of synthetic chemistry, 

 the world must be content to accept, for a long time to come, the 

 results of the intelligent labour of the cultivator of the soil and 

 the explorer of the forest. Improvement of the good plants we 

 now utilize, and the discovery of new ones, must remain the care 

 of large numbers of diligent students and assiduous workmen. 

 So that, in fact, our question resolves itself into this : Can these 

 practical investigators hope to make any substantial advance ? 



It seems clear that, except in modern times, useful plants have 

 been selected almost wholly by chance, and it may well be said 

 that a selection by accident is no selection at all. Nowadays, 

 the new selections are based on analogy. One of the most 

 striking illustrations of the modern method is afforded by the 

 utilization of bamboo fibre for electric lamps. 



Some of the classes of useful plants must be passed by without 

 present discussion ; others alluded to slightly, while still other 

 groups fairly representative of selection and improvement will 

 be more fully described. In this latter class would naturally 

 come, of course, the food-plants known as 



I, The Cereals. 



Let us look first at these. 



The species of grasses which yield these seed-like fruits, or 

 as we might call them for our purpose seeds, are numerous ; 

 twenty of them are cultivated largely in the Old World, but 

 only six of them are likely to be very familiar to you — namely, 

 wheat, rice, barley, oats, rye, and maize. The last of these is of 

 American origin, despite doubts which have been cast upon it. 

 It was not known in the Old World until after the discovery of 

 the New. It has probably been very long in cultivation. The 

 others all belong to the Old World, Wheat and barley have 

 been cultivated from the earliest times ; according to De 

 Candolle, the chief authority in these matters, about four 

 thousand years. Later came rye and oats, both of which have 

 been known in cultivation for at least two thousand years. 

 Even the shorter of these periods gives time enough for wide 

 variation, and as is to be expected there are numerous varieties 

 of them all. For instance, Vilmorin, in 1880, figured sixty-six 

 varieties of wheat with plainly distinguishable characters. 



If the Chinese records are to be trusted, rice has been culti- 

 vated for a period much longer than that assigned by our history 

 and traditions to the other cereals, and the varieties are corre- 

 spondingly numerous. It is said that in Japan above three 

 hundred varieties are grown on irrigated lands, and more than 

 one hundred on uplands. 



W^ith the possible exception of rice, not one of the species of 

 cereals is certainly known in the wild state. 



It is out of our power to predict how much time would 

 elapse before satisfactory substitutes for our cereals could be 

 found. In the improvement of the grains of grasses other than 

 those which have been very long under cultivation, experiments 

 have been few, scattered, and indecisive. Therefore we .are as 

 badly off for time-ratios as rre the geologists and archaeologists 

 in their statements of elapsed periods. It is impossible for us 

 to ignore the fact that there appear to be occasions in the life of 



