2009(2) : “Exploring Diversity in Past and Present” (Written Sources)

Tapuscrit inédit n°6-43 daté du 10 juillet 2009 (3+6 feuillets). Note sur l’abondance des sources écrites, l’inefficacité des banques de données, suivie de la reprise du texte précédent (Crops and Agricultural Development…) [2009(2).pdf]


(Written sources)

In many areas of research, the main problem is that written sources are few and far between. As far as plants are concerned, the problem may be that their number is overwhelming. Forty years ago, Uphof’s Dictionary of Economic Plants (1968) provided a bibliography of about 1400 references. A few years later, S. Rehm and G. Espig listed exactly 1577 references in Die Kultupflanzen der Tropen and Subtropen (1976). But the number of references given in a book is necessarily limited by factors such as the point of view of the author, the languages he or she can read, the time he or she could spare for it, the constraints of the publisher, etc. The real number may be much larger, although nobody really knows. On useful plants in modern times since, say, the 17th century, the number of written sources must be in the order of several tens (if not hundreds) of thousands, in a score of different languages. No one, even after having spent a whole life on the matter (which would be impossible anyway), can be expected to have more than a very partial view on the whole matter.

One cause of this state of affairs is that the number of “useful” species is itself enormous. In Les fondements biologiques de la géographie humaine, published in 1943, Max Sorre quotes figures in the order of 2700 to 2900 edible species. The number of species mentioned in Die Kulturpflanzen… is still in the order of 2500. The total number of “economic” plants that have an entry in the Dictionary of Uphof is about 10000. The most recent evaluation I was provided with (Chauvet 2009) is between 7 and 8000 cultivated plants, and between 20 and 30000 useful plants. But this is only a “reasonable” estimate. Depending on the number of species each author identifies within the same genus, and on what is thought to make a species to be counted as useful, real estimates may be much higher; there is one approaching 90000 species. To cope with the problem, one immediately thinks of data banks. But even data banks might not be a miracle solution. More than 30 of them have been recorded by Chauvet, some of general use, some restricted to one continent, one country or one category of plants, etc. So that exploring data banks could soon become a full-time business too.

Are these remarks relevant here? Frankly, I do not know. The only point I want to make is that, whatever the plant we are interested in, there are probably more written sources about it than we can imagine. The best example I can think of is that of a tinctorial plant named in French maurelle or tournesol (Croton tinctorius L., Chrozophora tinctoria A. Juss., nothing to do with the sunflower). This was a wild plant, gathered by the inhabitants of Grand-Gallargues (halfway between Nîmes and Montpellier) within an area extending two to three hundred kilometres east and west of their village. Once brought in at home, the plants were crushed and pressed, their juice was put to imbibe clothes (locally drapeaux) which after drying were finally laid out on fresh manure heaps. When they had thus acquired the desired blue colour, the drapeaux were sent to Holland where the blue dye was extracted and used, mainly in confectionery. Some authors assert that the business was already attested in the 15th century. It went on without important changes (or so it seems) until the 1830s, when, because the wild grounds where the maurelle grew naturally became scarce, some plant growers began to put it into cultivation – which was of little use anyway, since it was soon to be made obsolete by the development of synthetic dyes.

This is only the summary of a short note I have written recently (Sigaut 2007), after having found by chance a few 19th century written sources on the subject. I had no time to go any further, but as usual, the sources I had access to were conducive to others. And although I cannot propose any definite number, I am pretty sure that if a complete research could be done on this rather unimportant plant, the number of written sources would be found in the order of several hundreds, in at least three languages (Latin, French, Dutch). This is another way, more concrete than data banks hopefully, to pose the problem of written sources.

I have just said that the maurelle was an unimportant plant. From an economic point of view, this is undeniable. The inhabitants of Grand-Gallargues were never more than one or two thousand, they did not all make their living by it, and even if we add the merchants who carried the drapeaux to Holland and the workers who extracted and used the dye there, the grand total of people concerned must never have exceeded, say, four to five thousand. On an European scale, this is negligible. But it is not uninteresting. For here is a plant that was always gathered wild for centuries, although it was the object of a regular commerce and of a sophisticated industry. The maurelle does not fit into our nice but artificial categories. As I see it, the true question is: how many such unimportant plants were there, which are practically never heard of nowadays? And if they look unimportant taken one by one, are they still unimportant taken all together?

If we turn to oil-plants, the question is about the same, only on a still larger scale. For most plants produce seeds, and most seeds contain a certain percentage of oil, so that most plants can be oil-producing, at least virtually. In fact, what makes a plant oil-producing or not is, 1° the facility/difficulty to extract its oil, which is a matter of implements and techniques, and 2° the uses to which this oil can be put. Both are rather complex matters, on which there is an extensive literature. But what I know of this literature has been found by chance (exactly like in the maurelle case), not by consulting bibliographies or data banks. A book such as Fabrication et raffinage des huiles végétales – Manuel à l’usage des fabricants, raffineurs, courtiers et négociants en huiles, by J. Fritsch (Paris, H. Desforges, 1905, xv-593 p.), although by all accounts totally obsolete, is the best introduction into the matter I have been able to find. It deals mainly with the techniques for extracting and refining oils, but it also records more than 120 species of oil-producing plants of economic importance all over the world. This is only one example among many: books like this one also exist in most European languages (some of them being quoted by Fritsch himself).

The Fritsch handbook was written at a time when the commerce of such products was flourishing on a world-wide scale, with the consequence that the local production of vegetable oils in “developed” countries was at a minimum. But there were times when the situation was reversed. During World War II, for instance, France was cut off from foreign countries, so that the government made efforts to revive the production of oil from old-fashioned sources such as beechnuts, horse-chestnuts, pumpkin seeds, grape seeds, etc. In fact, oil had been extracted from some of such plants for ages, but only in particular areas, and it took the constraints of scarcity to make them an object of serious attention again. A booklet like Les plantes à huile, by M. Jouven (Paris, Éd. de Montsouris, 1942, 160 p.) is a pretty good example of this “scarcity literature”. Similarly, a number of pamphlets enhancing the production of oil from indigenous plants were published during the French Revolution, in the 1790s, when political events caused exceptionally long scarcities. Since all European countries have had their own times of scarcity, it is to be guessed that they have had also the attendant literature.

In the last decades, most written sources have come from ethnologists or museum keepers. One of the best examples I know of is Tradycyjne olejarstwo w Polsce, by Henryk Olszański (Sanok 1989, Muzeum Budownictwa Ludowego). It is in this book that I found a very important detail, namely that the seeds of weeds, resulting from the winnowing and sieving of the main cereals, were usually carried to the oil mill. It would be quite interesting to check whether this practice was in use in countries other than Poland.

Many other remarks could be made. As a conclusion, the two points I want to stress are, 1° that as far as the uses of plants are concerned, the main problem is that the number of written sources is huge, 2° so huge in fact that I have doubts on the usefulness of extant bibliographies and data banks. For the time being at least, it may still be more expedient to rely on flair and chance to find one’s way into the mass of relevant literature.



Chauvet, Michel (2009), Note sur les systèmes d’information sur les plantes utiles (unpublished paper, 9 p.).

Sigaut, François (2007), Quelques mots sur le tournesol, in A. Durand (ed.), Plantes exploitées Plantes cultivées, Aix-en-provence, Publications de l’Université de Provence, pp. 171-177.


François Sigaut
Le 10 juillet 2009