Aug. I, 1872] 



NATURE 



263 



SPONTANEOUS APPEARANCE OF EXOTIC 

 FORAGE PLANTS IN FRANCE AFTER THE 

 LATE WAR 

 T N a C'immunication lately made to the Paris Academy, 

 -■■ M. Vibraye states the fact of certain exotic forage 

 plants having appeared in considerable numbers in the 

 central parts of France, after the stay of the army in these 

 localities. He gives the followfing account of these plants : 

 " Their appearance, no doubt, results from forage sup- 

 plied from abroad, the seeds of which had fallen into the 

 ground. At the present time several iMcditerranean plants, 

 (chiefly Algerian), having braved the cold of an exception- 

 ally severe winter, are being largely propagated, forming 

 extensive meadows, and changing soil that was formerly 

 arid, and produced no vegetation of importance, to veri- 

 table oases. This may probably lead to the definitive 

 introduction of a large number of plants into a more 

 northern region than that which they appear naturally to 

 occupy and to prefer. 



" The tirst notion of the possibility of such plants being 

 brought into French soil, through the fodder consump- 

 tion of the army, arose in 1S70. A botanist of Strasburg, 

 M. Buchinger, wrote to M. Franchet (conservator of my 

 collections) some days before the investment of the place 

 that, on examining the fodder which was being given 

 to the horses, he had found in it forty-four species of 

 plants belonging to the iMediterranean region, and most 

 of which were Algerian. He suggested to M. Franchet 

 to make observations, and see whether some of these plants 

 would not appear in the soil. The prediction was veri- 

 fied ; and in April 1S71, M. Franchet found two exotic 

 centauries, and communicated the fact to M. Nouel, the 

 director of the Orleans Museum. Since then these two 

 botanists have made minute researches on the subject, and 

 have discovered many more such plants. This is, briefly, 

 the history of the discovery. The places where the pheno- 

 menon has been best obserxed are in the Department of 

 the I.oireet-Cher : (i) on the right bank of the Loire, 

 near the railway ; (2) on the left bank, the country about 

 Blois. Then, too, in the Communes of Cour, and more 

 especially of Cheverny, which districts were successively 

 occupied. Observations have also been made at Orleans, 

 on the Boulevard Saint Jean, and the Isle of Arrault. 



" I shall best recount these observations by giving them 

 as they were written down in the order of date. 



" On the iSih March, 1S72, certain new plants, observed 

 the previous year at Blois and Orleans, had increased con- 

 siderably on arid soil, which formerly bore only some poor 

 and stunted herbs. Each of the districts furnished about 

 90 to 100 species. But the species were not the same in 

 each district, and the total number of species met with, 

 was 157, belonging to twenty-one families, as follows : — 

 Ranunculacea' . 3 Compositce . 2S 



Resedacea: . . i Convolvulaceii:^ i 



Crucifera; . . . S Borragiiiere . i 



Silenea; ... 5 Verbascece . i 



Alsinea; . . . i Plantaginea; . i 



Bineas . . . . i Labiata; . , 2 



Malvacea; . . . S Amaranthacea; i 



(leraiiiacen; . . 7 .Salsolaceaj . 2 



Leguminosa; . . 52 Polygoneie . 1 



Umbellifera; . . 4 Clraminea; . 2S 



l)ip3acea; . . . i 



Entire total . . . 157 



'■ The first observations could not be considered quite 

 definiiiv'e, and there were some species which it was, per- 

 haps, a little premature to determine ; but after deduc- 

 tions made on this account there remained 140 species ; 

 a number much larger than that of the plants on the best 

 meadow lands in France, which, according to botanists, 

 do not furnish more than 90 to 100 species. 



'• It will be seen that the Leguminos;"e (52 species) form 

 about one-third of the whole, while the Graminea; and 



the Composite^ form each about one-fifth (28 species). 

 Among the Leguminosa; trefoil and lucerne predominated ; 

 12 kinds of trifoHum were counted, and 10 or 11 of medi- 

 c.igo ; the 28 Compositce belonged to 21 genera, and the 

 28 Graminere to 16 different genera. Two thirds of these 

 fo^rage plants are annuals or biennials. 



" On the 1 2th April afresh examination of the Blois dis- 

 trict showed that many of the species, and especially the 

 medicagos, had not only persisted but been propagated 

 from seeds. Unfortunately for the full development of 

 this, the land was used as a pasturage for sheep, which 

 devoured the plants in proportion to their growth, and up- 

 rooted many with their feet, the arid soil having little 

 cohesion. At Cheverny, where I had enclosed certain 

 spaces, several Algerian plants attained a superb growth ; 

 among these, trefoil, melilot, phalaris, and alopecurus. 



" By the 19th April it was evident that not only a large 

 number of species had persisted, but that from being rare 

 and poor the previous year, they had developed to a won- 

 derful extent, notably the Alopecurus utricidatus, Vidpia 

 ligustica, Avcna harhata, Tri/oliiun nigrcsccns, TrifoUum 

 isthoccrpum, all southern and forage plants. Tht Medi- 

 cagos spharocarpa and pcntacycla reappeared in great 

 abundance where they had escaped the cattle, or the sickles 

 of women in search of herbs. It was difficult to persuade 

 these herb-gatherers to a temporary self-sacrifice with the 

 view of ultimate advantage in respect of forage. 



'■ On the 27th April my attention was called to the large 

 number of annuals and biennials disseminated. The 

 annual plants, which De CandoUe called monocarpian, 

 because they terminated their existence by a perfect aad 

 unique fructification, are invariably reproduced by the dis- 

 semination of their seeds when they have come to matu- 

 rity ; the individual dies, while the species becomes 

 perennial ; which duration, on the other hand, is tempor- 

 arily acquired by the individual, when a scythe, or the 

 grazing of cattle, retards the last and indispensable phase 

 of the plant's existence. 



"At this date, April 27, trefoil and lucerne promised to 

 be very abundant in the Blois district. By the ist of May 

 an incessant appearance of new species was noticed ; and 

 it seemed beyond a doubt that before the end of the sea- 

 son the four localities of Blois, Cheverny, Vendome, and 

 Orleans, would furnish not fewer than 200 species, of which 

 170 at least were peculiar to meadows and pasture lands. 

 " On the 3rd May a new fact presented itself During 

 the war a forage depot had stood at the side of the mar- 

 ket place of Cour Cheverny, but last year no appearance 

 of any new plant had been discovered there, notwithstand- 

 ing careful search. On the 3rd some twelve species of 

 foreign forage plants made their appearance, and others 

 were expected. This shows that the seeds had remained 

 in the soil for sixteen months without alteration of their 

 germinating properties. This is an interesting fact, and 

 a corollary of a law of rotation observed in all natural 

 meadows, viz., the temporary disappearance of dominant 

 species, yielding for an indeterminate period to new types, 

 which they by-and-by come to displace, when they meet 

 with certain favouring atmospheric influences, not very 

 fully understood. 



'■ The Algerian plants withstood successfully the frost of 

 the 1 2th May, which did much damage to our vines and 

 the shoots of certain trees, especially indigenous conifers." 

 i\I. Vibraye, in closing his note, speaks of the above 

 phenomena as being quite an e\-ent. It is not the 

 ephemeral appearance of a few plants sparsely dissemi- 

 nated, raising the problematical hope of fixing in the soil 

 a useful vegetable— it is an exodus ; the migration, not of 

 a modest Jiorulc, but of a flora, independent and com- 

 plete. It is, in a word, a treasure v/hich the central dis- 

 tricts of France are called on to study and to appropri.ite. 

 He argues that the propagation of these plants should not 

 be lefc to chance, but that human skill should be brought 

 to bear on it. A. B. M. 



