fontana, Callitriche verna, Cardamine hirsuta, Epilobium tetragonum, and many others.

On the other hand, it must be recollected that there are other causes besides antiquity and facility for migration, that determine the distribution of plants; these are their power, mentioned above, of invading and effecting a settlement in a country preoccupied with its own species, and their adaptability to various climates: with regard to the first of these points, it is of more importance than is generally assumed, and I have alluded to its effects under Sonchus, in the body of this work. As regards climates, the plants mentioned above seem wonderfully indifferent to its effects.*

Again, even though we may safely pronounce most species of ubiquitous plants to have outlived many geological changes, we may not reverse the position, and assume local species to be amongst the most recently created; for whether (as has been conjectured) species, like individuals, die out in the course of time, following some inscrutable law whose operations we have not yet traced, or whether (as in some instances we know to be the case) they are destroyed by natural causes (geological or others), they must in either case become scarce and local while they are in process of disappearance.

In the above speculative review of some of the causes which appear to affect the life and range of species in the vegetable kingdom, I have not touched upon one point, namely, that which concerns the original introduction of existing species of plants upon the earth. I have assumed that they have existed for ages in the forms they now retain, that assumption agreeing, in my opinion, with the facts elicited by a survey of all the phenomena they present, and, according to the most eminent zoologists, with those laws that govern animal life also; but there is nothing in what is assumed above, in favor of the antiquity of species and their wide distribution, that is inconsistent with any theory of their origin that the speculator may adopt. My object has not so much been to ascertain what may, or may not, have been the original condition of species, as to show that, granting more scope for variation than is generally allowed, still there are no unassailable grounds for concluding that they now vary so as to obliterate specific character; in other words, I have endeavored to show that they are, for all practical purposes of progress in botanical science, to be regarded as permanently distinct creations, which have survived great geological changes, and which will either die out, or be destroyed, with their distinctive marks unchanged. We have direct evidence of the impoverishment of the flora of the globe, in the extinction of many most peculiar insular species within the last century; but whether the balance of nature is kept up by the consequent increase of the remainder in individuals, or by the sudden creation of new ones, does not appear, nor have we any means of knowing if the expression of an opinion be insisted on, I should be induced to follow the example of an eminent astronomer,

* Mr. Watson (Cybele Britannica) gives the range of Callitriche in Britain alone as including mean temperatures of 40° to 52°, and as ascending from the level of the sea to nearly 2000 feet in the East Highlands of Scotland. Montia, according to the same authority, enjoys a range of 56° to 520, and ascends to 3300 feet; Epilobium, a temperature of 40° to 51°, and ascends to 2000 feet; Cardamine, a temperature of 37° to 52°, and ascends to 3000 feet.

who, when the question was put to him, as to whether the planets are inhabited, replied that the earth was so, and left his querist to argue from analogy. So with regard to species, we know that they perish suddenly or gradually, without varying into other forms to take their place as species, from which established premiss the speculator may draw his own conclusions.

To those who may accuse me of giving way to hasty generalization or loose speculation on the antiquity and dispersion of plants over parts of the Southern Hemisphere, I may answer, that no speculation is idle or fruitless, that is not opposed to truth or to probability, and which, whilst it co-ordinates a body of well established facts, does so without violence to nature, and with a due regard to the possible results of future discoveries. I may add, that after twelve years' devotion to the laborious accumulation and arrangement of facts in the field and closet, untrammelled by any theories to combat or vindicate, I have thought that I might bring forward the conclusions to which my studies have led me, with less chance of incurring such a reproach, than those would, who with far better abilities and judgment, have not had my experience and opportunities."

The hypothesis that these insular floras are the remains of larger floras greatly reduced or verging to extinction, will be found remarkably applicable, if we mistake not to the case of the Sandwich Islands; many of the characteristic species of which appear to be represented by comparatively few individuals, as if waning to extinction along with the Hawaian race.

The general idea here so ably set forth by Dr. Hooker, in respect to the Antarctic and South Pacific floras, is a very important one, and worthy of the most extended and critical examination. Its establishment, moreover, by satisfactory evidence, would destroy one of the strongest grounds upon which the doctrine of the multiple origin of species (at least in the form maintained by Schouw) is supported. To complete the view, and fairly to exhibit the grounds upon which these theoretical conclusions are based, we should embrace in our extracts a large part of the remaining chapter; on the physiognomy and affinities of the New Zealand Flora, and on the variation of New Zealand species. But the necessary limits of our article forbid. A few facts regarding the more striking peculiarities of the New Zealand flora may be collected. The large proportion, both relatively and absolutely, of the Cryptogamia, and especially of Ferns, has already been noted. "A paucity of Grasses, and absence of Leguminosa, and abundance of bushes and Ferns, and a want of annual plants, are the prevalent features of the open country; whilst the forests abound. in Cryptogamia, in Phænogamic plants with obscure and green flowers, and very often of obscure and little known natural orders." The number of natural orders of the Phænogamic plants is remarkably large in proportion to the genera, even for an insular flora; being 92 to 282, or about one to three: while the genera

are to the species as 282 to 730, each genus having on the average only 2 species: so that the species average but eight for each order. This makes it one of the most difficult floras in the world for a beginner, who must know a natural order for every eight species. How recondite, vague, and unsatisfactory the natural system of Botany must appear to the New Zealand student!

Of the largest natural orders, as respects the number of species, the individuals are often so few that none of them form prominent features in the landscape. The Coniferæ prove to be the most prevalent family; but the majority of their species. are not social but grow intermixed with the trees, so as to give no character to the landscape ;—a case just opposite to what occurs in the northern hemisphere, at least in North America, where the species are few, but mostly social, and existing in a vast number of individuals, which often occupy considerable tracts almost exclusively, and thus strikingly impress their features upon the landscape.

The number of kinds of trees is very large in proportion to the herbaceous plants; as there are 113 Phænogamous trees, including shrubs above twenty feet high, or one-sixth of the flora, while in England there are not more than 35 native trees, in a much larger flora.

A remarkably large proportion of the Phænogamous flora of New Zealand consists of absolutely peculiar plants of these there are 26 genera and 507 species; or more than two-thirds of the whole. The greater part of these are Exogens. Of the remaining third, consisting of plants common to New Zealand and other countries:

"193 species, or nearly one-fourth of the whole, are Australian. 89 species, or nearly one-eighth of the whole, are South American.

77 species, or nearly one-tenth of the whole, are common to both the above.

60 species, or nearly one-twelvth of the whole, are European. 50 species, or nearly one-sixteenth of the whole, are Antarctic Islands, Fuegian, &c."

These several elements in the New Zealand flora, whether as represented by identical or cognate species, are in turn subjected to a critical analysis. The following extract, respecting the Australian element, is interesting from its direct bearing on the question of transport by water.

"If the number of plants common to Australia and New Zealand is great, and quite unaccountable for by transport, the absence of certain very extensive groups of the former country is still more incompatible with the theory of extensive migration by oceanic or aerial currents. This absence is most conspicuous in the case of Eucalypti, and almost every other genus of Myrtacea, of the whole immense genus of Acacia, SECOND SERIES, Vol. XVII, No. 51.-May, 1854.

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and of its numerous Australian congeners, with the single exception of Clianthus, of which there are but two known species, one in Australia, and the other in New Zealand and Norfolk Island.

The rarity of Proteacea, Rutaceæ, and Stylideæ, and the absence of Casuarina and Callitris, of any Goodenia but G. littoralis (equally found in South America), of Tremandrea, Dilleniacea, and of various genera of Monocotyledones, admit of no explanation consistent with migration over water having introduced more than a very few of the plants common to these tracts of land. Considering that Eucalypti form the most prevalent forest feature over the greater part of South and East Australia, rivalled by the Leguminosa alone, and that both these Orders (the latter especially) are admirably adapted constitutionally for transport, and that the species are not particularly local or scarce, and grow well wherever sown, the fact of their absence from New Zealand cannot be too strongly pressed on the attention of the botanical geographer; for it is the main cause of the difference between the floras of these two great masses of land being much greater than that between any two equally large contiguous ones on the face of the globe. If no theory of transport will account for these facts, still less will any of variation; for of the three genera of Leguminosa which do inhabit New Zealand, none favor such a theory; one, Clianthus, I have just mentioned; the second, Edwardsia, consists of one tree, identical with a Juan Fernandez and Chilian one, and unknown in New Holland; and the third genus (Carmichalia) is quite peculiar, and consists of a few species feebly allied to some New Holland plants, but exceedingly different in structure from any of that extensive Natural Order.”

Dr. Hooker then appends a carefully prepared table of 228 phænogamous species which may be said to represent each other in two or all the three South temperate masses of land, viz., New Zealand (including Auckland and Campbell's Islands), Australia (including Tasmania), and extra-tropical South America, including the Falkland Islands; the list being confined to cases of real and usually very close botanical affiuity, to the exclusion of analogical resemblances, however striking. The list is by no means overstrained, nor as full as it might be; since one or two more good instances have occurred to our memory while looking over its columns. On comparing together the Australian and New Zealand columns, we find only fourteen blanks, not filled by known representative species; a similar comparison of the New Zealand and South American columns shows forty-six blanks, sixteen of which are among the Endogens.

On fairly weighing all this testimony, the botanist will perhaps accede to our author's conclusion,-viz., that the floras of these three great areas of land in southern latitudes "exhibit a botanical relationship as strong as that which prevails throughout the. lands within the Arctic northern temperate zones: and which is not to be accounted for by any theory of transport or of variation; but which is agreeable to the hypothesis of all being members of a once more extensive flora, which has been broken up by geological and climatic causes."

A. G.

ART. XXXVII.-Remarks on the Mineral species Algerite; by T. S. HUNT.

In this Journal for July, 1849, I published a description by Mr. Alger, of a mineral from Franklin, N. J., together with an analysis of it by myself, from which I was led to consider it a new species, and to give it the name of Algerite. It was again analyzed by Mr. R. Crossley, whose results will be found in this Journal for July, 1850. The mineral had been described as having the form of an oblique rhombic prism, M: M = 94°, but Mr. Dana has satisfied himself that the crystal is really a square prism. The hardness is 30-35 (Alger, Crossley); density 2-6972-712 (Hunt), 2-78 (Crossley). The mineral which is imbedded in a white coarse-grained crystalline limestone, is subject to decomposition in the weathered portions of the rock, but as I stated in my paper, "the crystals selected for analysis were hard, semitranslucent and undecomposed; their powder when elutriated and carefully dried, was of a buff color, which was not changed by ignition." Mr. Crossley remarks that in his case "many of the crystals were incrusted with idocrase, and in some instances penetrated so much that it required great caution to secure portions free from that mineral." He rejected all decomposed portions, and analyzed only pure honey-yellow fragments. The results of the two analyses are as follows:

A subsequent incomplete analysis gave me, Silica 49-42, alumina 25 67, peroxyd of iron 1-93, carbonate of lime 3.57, water 6.18, magnesia and alkalies by difference 13-23. My analysis differs from that of Mr. Crossley in the smaller amount of magnesia which is replaced by water, a case analogous to that of aspasiolite and iolite, or serpentine and chrysolite, which are found in the same localities and even in the same crystal. The question whether these differences are to be attributed to a subsequent alteration of the minerals, by removing magnesia and substituting water, or to the original association of homeomorphous, chemically homologous species, is as yet unsettled. The latter view is maintained by Scheerer, whose opinions will be found in this Journal [2] vols. v, p. 388, and vi, p. 199; and also cited with some further considerations to the same effect, in a paper by myself, published in the last volume of this Journal, of which see page 217.