Art. LIX.—Remarks on Dr. H. von Jhering's Paper “On the Ancient Relations between New Zealand and South America.”
Translated from “Das Ausland,” Stuttgart, 20th July, 1891, by H. Suter, of Christchurch. Communicated by Professor F. W. Hutton.
[Read before the Philosophical Institute of Canterbury, 5th May, 1892.]
Dr. Von Jhering's remarks on the fauna of South America apply to a large extent to the flora also, which agrees with the Australian type in a most striking manner. Mosses are known from Chili which can hardly be distinguished from true Australian species. I was formerly of opinion that the moss flora of Chili and Tierra del Fuego only was related to that of Australia, but I have recently received mosses which prove that this flora extends to Argentina, and even to the Sierra Geral, in south Brazil. This fact evidently coincides with another, long since known—viz., that the Sierra Geral,
and especially that portion called the Sierra do Oratorio, has still Araucarias, whose next of kin is at present found only in the Australian region. The readiest explanation of this is that the American and Australian botanical regions are of the same age as Australia itself. A part of south Africa must also be included, especially that part in which the fundamental form of Proteaceœ is found.
It should be also mentioned that the Pacific shores of America, not only in Chili (and perhaps Peru), but also in Lower California and as far as north of British Columbia, bear a flora which is mixed with forms which to some extent remind one of Australian types—a heterogeneous combination differing essentially from the vegetable world east of the Rocky Mountains.
But to which geological period must we refer this older flora? I am of opinion that the presence of Araucaria in Brazil should lead us on the right track. When we remember the important part these remarkable plants played in the Carboniferous and later periods, it would seem that they have been here preserved to the present day from, perhaps, the youngest of these periods. Similar observations can be made on some mosses. It is only a short time since I obtained from a bryologist of Rio Grande do Sul a moss from the Sierra Geral which so strikingly corresponded with the true Australian Dicnemonella that I felt uncertain whether a mistake had not been made. Soon afterwards my nephew—who is collecting in that place—sent me the same moss from the heights of the Sierra. I was exceedingly astonished at receiving from the Araucaria forests of Brazil a moss type which I should without any hesitation have assigned to Australia if I had been asked to name its native country.
Our phyto-geographers have long since known the relation of Chili and Tierra del Fuego to Australia, but not many conclusions have been drawn about it. No doubt many secrets are still hidden in South America, the investigation of which may very likely open out new ways of considering the faunas and floras of countries, perhaps even their mineralogy and geology. When speaking of the Fuegians, Von Martius says that here one stands before one of the many mysteries which still remain to be solved in the ethnography of South America.
It is my firm conviction that the present flora and fauna of the world contain many forms belonging to very old periods. I am not thinking of the hippopotamus, the giraffe, or the Australian types of animals. No doubt there are living organisms the origin of which reaches back far beyond the Tertiary era—such, for instance, as the singular Cycadeœ of Australia, south Africa, Japan, &c. The genus Lingula, belonging to the Brachiopoda, is one of those which from the
first appearance of animal life in the Cambrian strata have lived on up to the present time. It is represented in each period by several species, and shows throughout the whole line such a striking uniformity in its external characters that distinguishing between the species is often exceedingly difficult.
With regard to the Atlantis, which is mentioned by Dr. Von Jhering, I have dealt with that subject in the “Botanischer Zeitung,” and am of opinion, with Wallace, that that point is settled. In Ireland a few mosses occur which are found nowhere else in Europe, but have their nearest allies in the tropics—Daltonia splachnoides and Hookeria lœte-virens. I can only consider them as remnants of a former vegetation which included many more tropical forms, and not due to any great difference in geological time. In connection with this is the occurrence of a phanerogamic grass-like plant—Eriocaulon septentrionale—on the Isle of Man, the only representative of the tropical family Eriocauleœ.430 The fact that these plants have maintained themselves in their home can only be explained by the existence of the warm Gulf Stream, which flows round Great Britain, first striking Ireland. The Gulf Stream must therefore have been in existence ever since these plants had their present habitat; and if this is so there cannot have been an Atlantis, which would have barricaded off the Gulf Stream. Consequently I cannot agree with Unger's theory. By this I do not mean to imply that land bridges never existed. In fact, I fancy I know one myself. But I am of opinion that they are of rare occurrence.
In southern Norway, especially in the Bergen-Stift, there are a good number of plants which are not related to those of the rest of the Norwegian flora, but correspond with the Scottish flora. In the first place there is a moss, œdipodium griffithsi, which is only found in Scotland—where it was first discovered—and in Bergen-Stift: a moss which differs essentially and in many respects from all its allies in the family Splachnaceœ, and therefore stands quite isolated. This moss I also consider to be a remnant of an extinct flora. But how came it to Norway? Or how is such a distant occurrence to be explained? Simply in this way: that at a certain geological time there was a land connection, perhaps only imperfect, between Scotland and Norway—a communication which was broken up by the waves of the North Atlantic Ocean, and of which the Shetland and Lofoden Islands may be the remnants. This also easily explains why Heligoland is but a small remnant of a land which, according to Adam v. Bremen, formerly extended over many square miles. More-
[Footnote] * This is not quite correct.—F. W. H.
over, the many Lias fossils which I saw in 1839 and 1840 in a collection at Jever, nearly all of which were changed into pyrites, point to the same fact…. There cannot, therefore, be here any question of subsidence, as assumed by Dr. Von Jhering; the bridge between Norway and Scotland was simply broken through and washed away by the waves….
But, to return: As before mentioned, Dicnemonella kunerti (mihi), the nearest allies of which occur in great numbers only in New South Wales, is found on the Sierra Geral, in Brazil. A somewhat similar case was recently noticed by me. I was greatly astonished, when naming the collection of mosses of the late Mr. Hildebrant—who unfortunately died while still young in Madagascar—to find a type which very characteristically united the flora of the Cordilleras with that of central Madagascar — viz., the genus Lindigia. But my astonishment increased when I found also a second and not less characteristic form in the genus Streptopogon. How came these two American endemic moss types to Madagascar? The importance of the matter is much increased by the entomological collections, for the Lepidoptera and the Coleoptera confirmed what I had already found in the mosses. Can a land bridge have existed at one time between Madagascar and the New World; and, if so, how could it have extended from the Andes to Madagascar, as the said mosses live only at medium heights on the Cordilleras? Again, I recently received a collection from a young Swede—Dusèn—from the Cameroon, in tropical west Africa, and found in it a new Lindigia, but from low-lying regions. But, as I knew it to exist in Africa, it was only the fact of its occurrence in low-lying regions that was surprising to me. But the fact in itself formed only a fresh point of evidence; for it is well known to the initiated that in the west African tropical zone many plants are met with which have corresponding types in South America. Several mosses are even identical with those of tropical America—viz., Octoblepharum albidum, which goes down to subtropical South Africa; and Rhizogonium spiniforme, which is also found on the Comoro Islands. Ascending from the lower regions of the Cameroon to its high plateaux towards Goetterberg, a believer in bridges would be compelled to doubt, for at these considerable heights we meet with corresponding floras of Mexico and Abyssinia!!, an observation already made by Sir J. Hooker when examining the collections of the German botanist Mann. But this is not all. Everywhere in tropical lowlands where malaria is brewed, no matter in what part of the earth, but especially in the mangrove forests of brackish water, a moss flora occurs the types of which are the same everywhere, and the species are so remarkably alike that
it takes a great deal of trouble to distinguish and characterize them by sharp diagnoses. I have called these mosses “malaria mosses,” and know at once the kind of climate of their home, wherever they may have come from. What is the significance of this? Nothing else but that the same climatic regions have produced the same types—either the same or, at any rate, very similar species. There can be no question of migration, because the malaria mosses occur far in the interior of a continent as well as on its coasts, provided the low-lying land is tropical. This was strikingly shown by the mosses collected by Dr. George Schweinfurth in the lowlands of central Africa, especially in the districts of Niam-Niam, Monbuttu, &c., and which were intrusted to me for determination.
I come now to a still more remarkable circumstance—viz., that the floras of certain districts are not homogeneous, but exhibit amongst their warp a woof which has nothing in common with it, but exhibits the stamp of a totally different flora. I have already mentioned it in the Australian type, which beyond a doubt belongs to the oldest forms of plant-organization on our globe. It is well known to phyto-geographers that this Australian type extends in Chili down to Tierra del Fuego and its islands, and eastwards as far as Brazil. In this large territory, including the Island of Chiloë, mosses are met with which resemble with wonderful closeness species from New Zealand. But the same thing is seen in Africa also, especially south Africa, which in its Proteaceœ really repeats Australia. West Australia, which has in every respect a totally different flora from eastern Australia and its islands, shows forms which are peculiar to Africa, and which must be very surprising to West Australian phyto-geographers—viz., the monkey bread-fruit tree, or baobab. Over the whole enormous extent of Africa there is only one species (Adansonia digitata); Australia has furnished a second in A. gregorii, but this is found in such an isolated region of the interior that the question, From which of these points did the type originate? has lost its sense. Australia did not receive it from Africa, nor did Africa receive it from Australia—it is autochthonous in both places; and one sees here once again that the same conditions of creation produced in different places the same type, only in different species. If this be not the case, the enigma cannot be explained by migration, for that necessarily includes the idea that the reproduction of the type was successful in one place only. This always makes on me the same impression as the idea of explaining the origin of organisms by deriving them from some other globe. What is gained by it? Nothing else but that the cause of origin is put further back; for, after all, one is obliged to ask, Where did the organisms of that strange globe come from?—they
must have originated somewhere. With such explanations, one wanders without knowing it in a circle, if one does not wish to arrive at the absurd conclusion that the creation of organisms was possible on one globe only. It is the same with migrations. I do not deny them when they are opportune, and I know very well that wind and weather, animals and men, are able to distribute species sometimes over large areas; but it is quite a different thing when we have to deal with the spreading of whole floras, sufficient to impress one district with the stamp of another, where all the species are united in an organic association, so that one cannot be understood without the other. This cannot ever have been accomplished by a migration of a mechanical nature.
Sufficient attention has not hitherto been paid to isolated types standing apart in floras. Examples are numerous, but I will mention only one of the genus of mosses—Drummondia. Its history is much the same as that of Adansonia. Originally it was discovered in North America as D. clavatella; afterwards I pointed out a second species—D. obtusifolia—in Chili; and finally the English traveller T. Thomson discovered a third species—D. thomsonii—in Thibet, on the heights of the Himalaya. How comes such a characteristic ground-form of the United States upon the Cordillera of Chili and upon the icy heights of central Asia? The answer is, Because the conditions of creation at all these three places on the earth produced it as the sequence of given circumstances. Any other answer is unscientific. Chemico-physical agencies produced it. Under this head it is possible to think of something, but any other explanation is unthinkable. But one can turn the spear if one fixes the eyes upon Australia. There, of course, the Australian types dominate in such large numbers that they give to the flora the characters of a former age. To the earlier German botanists, such as Dr. Behr, of Anhalt, it appeared remarkable that there are districts on the Australian Continent where, to the surprise of the observer, European forms were found at a time when no considerable immigration had taken place. But even if the immigration had been large it would not have mattered much, for, although the genera were European, the species were spontaneous. Whence did they come to Australia? Answer, From no other place than Australia itself, for they are not known in Europe. Even Africa has a claim to similarity like Europe. In South Australia a fern occurs with a considerable development of the stem—a species of the genus Todea. Only one species was known from South Africa (T. africana), which so closely resembles the Australian species that for some time they were thought to be identical; but their specific difference
is now known. This is a parallel case with the famous Adansonia.
But now comes the best proof. If we look backward for many hundreds of thousands of years, we see an Australian flora growing on the soil of Germany. Unger explained the origin of this flora by imagining the Atlantis as a land bridge for the migration of plants from Australia to Germany. After what has been said above, it is not worth while to criticize this idea. But I myself, from the fact of the former existence of an Australian flora in Europe, draw the conclusion, justified by what has been already said, that this flora was also autochthonous. This conclusion includes another—viz., that all flora-districts of Australian stamp must have been of the same geological age. A single glance at palæontology shows that each geological period had its own characteristic fauna and flora. What the causes were is still a question, but the fact is established. In many districts outside Australia these types have been preserved separately, and therefore we have to draw a third conclusion—viz., that our present flora-districts are the result of many preceding geological periods, here more, there less. This is very strikingly confirmed by the fact that the well-known tulip-tree (Liriodendron), with which we first got acquainted as L. tulipifera, from North America, was afterwards discovered in the district of the Yang-tse-kiang River, in China, in the form of L. procaccinii, a species already present in the Miocene of Europe. Consequently all explanations of origin by migrations and bridges cease, and we are forced back on the idea of autochthonous causes. And this is only a single example among many other occurrences which altogether negative what has been hitherto said about the transmutation of species.
Although not an unconditional believer in all the bridges adopted by Dr. Von Jhering, yet I am glad that he admits that there are Australian forms in South America, and connects them with those which we find at present in New Zealand and elsewhere in Australia, and that I meet with the opinion that the present continents have originated from former islands, which were united by successive elevations in different geological periods. I am also very pleased to see that Dr. Von Jhering is of exactly the same opinion as myself, that Darwinism will belong only to history after a few decennaries, so far as it tries to explain the origin of species.