limbo obovato concavo erosè crenulato, marcescentia. Stamina totidem, iisdemque alterna, hypogyna, exserta, paululum interiùs seposita, pariter marcescentia: filamenta longiuscula, angustissima, compressa, glabra: antheræ subrotundæ, biloculares, subdidymæ, ad medium peltæ modo filamentis impositæ: loculis ventricosis, ferè omnino solutis, rimâ longitudinali exteriùs dehiscentes. Ovarii rudimentum. FEM.-Calyx maris. Petala totidem, sed breviora et vix unguiculata. Staminum rudimentis rarò ullis. Pistillum: ovarium globosum, sessile, disco carnoso impositum, 3, 6, v. 9-loculare, ovulis solitariis: styli 3, brevissimi, in unum corpus triangulare coaliti: stigmata radiato-multifida: lobis 6 v. 9, patulis, basi dilatatis, subtùs percurrenti-carinatis, suprà sulco perangusto exaratis, pruinosis, apice truncatis, emarginatis v. bicorniculatis. Bacca sphærica, nunc depressa, apice leviter umbilicata, basi calyce persistente cincta, 2, 3, 6 v. 9-pyrena: caro parca: pyrenæ testâ osseâ monospermæ, erectæ, collaterales, elliptico-trigonæ, compressiusculæ, columellæ demum evanescentis angulis numero æqualibus per totam longitudinem adnatæ, dorso convexo sulcato, ad apicem puncto exiguo ferè perviæ. Semen ovoideum, cavitati pyrenæ conformis, basi chalazâ tuberculiformi atro-fuscâ instructum: testa simplici, membranaceâ, spadiceâ, reticulato-vasculari, apice puncto notatâ: albumen copiosissimum, densum, carnosum, aqueo-pallidum, hinc facie planiusculâ, inde convexum. Embryo teres, erectus, axilis, lacteus, albuminis ferè longitudine: cotyledones semicylindricæ, obtusæ, arctè applicatæ: radicula infera, recta, cylindracea, obtusa, cotyledonibus ferè triplo longior.

Frutices (utriusque orbis zonis temperatis proprii) humillimi, sempervirentes, facie ericoidea. Folia alterna, petiolo exigui complanato suffulta, margine revoluta, integerrima, exstipulata. Flores parvi, axillares solitarii, v. terminales glomerati.

EMPETRUM.

EMPETRI Sp. Linn. Juss.

Calyx 3-phyllus, coriaceus, basi squamis 6 imbricatis munitus. Petala 3. Stamina 3. Stigma 6-9-fidum. Bacca depressa, 6-9-pyrena.

Fruticuli (Europ. bor. et Magellan.) ramosissimi, procumbentes. Folia alterna, lineari-lingulata, obtusa, suprà plana, subtùs convexa et linea membranacea exarata, atro-viridia, nitida. Flores axillares, solitarii, sessiles, atro-sanguinei. Baccæ nigræ v. rubræ. Hùc E. nigrum, L. et E. rubrum, Vahl.

1

COREMA.

EMPETRI Sp. Linn. Juss.

Calyx 3-phyllus, membranaceus, basi nudus. Petala 3. Stamina 8. Stigma 6-fidum. Bacca globosa, 3-pyrena

Suffrutex (Europ. austr.) erectus, ramosissimus, rigidus, punctis resinosis adspersus. Folia undique sparsa, linearia, obtusa, patula, suprà planiuscula, margine revoluta. Flores terminales, glomerati, sessiles, disco piloso impositi, albi, majores. Capitula squamis villosis bracteolata. Baccæ albæ.

Hùc E. album, L.

CERATIOLA, Rich. in Mich. Fl. Amer. bor.

Calyx 2-phyllus, membranaceus, basi squamis 4 munitus. Petala 2, in tubum conniventia. Stamina 2. Stigma 6-fidum. Bacca globosa, 2-pyrena. Suffrutex (Amer. bor.) adscendens, ramosissimus, rigidus. Rami stricti, simplices. Folia alterna, patentia, acerosa, obtusa, glabra, nitida, viridia, subtùs sulco angustissimo exarata, suprà leviter canaliculata, semipollicem longa; nunc plurima approximata, quasi verticillata. Flores axillares, sessiles, plures (2-4), rarò solitarii; nunc (ad folia approximata scilicet) verticilli modo dispositi. Baccæ rubræ?

Hùc Ceratiola ericoides, Rich. in 1. c. 2. p. 221.

In order to render this treatise as complete as possible, besides giving a description of the group itself, I thought it important to add the characters of the genera. It is immaterial whether the Empetrece are to be regarded as a section of the Euphorbiaceæ, or as constituting a separate family. Their intimate affinity has, I trust, been satisfactorily shewn; and it also appears clearly evident, that the Euphorbiaceae, Stackhouseæ, Celastrinæ, and Rhamneæ, must follow each other in a natural arrangement, as Mr Brown seems disposed to think *.

* General Remarks on the Botany of Terra Australis.

Establishment of Vegetation at the Surface of the Globe *. WE have seen vegetation covering, with verdure and flowers, all parts of our globe; we have seen it extending itself from the bottom of the valleys to the most elevated places, resisting, in the plains, the burning rays of the sun, struggling upon the mountains with the frosts, bursting forth every summer from beneath the snows, and only stopping short at the zone of perpetual ice. But how does this vegetation come to cover the nakedness of rocks, to fix the mobility of sands, to implant itself in the strong gravel, to convert immense lakes into marshes, and these again into forests and fields? for such was, and such still is, the surface of the globe, in all places destitute of vegetation, whether in islands which have newly sprung from the bosom of the waters, or in tracts where the soil has been overturned by particular accidents, or deprived, by other circumstances, of their ancient verdure; such, also, do we find it, if we remove the layer, more or less thick, of earth which clothes it. This earth is, therefore, of new formation, as well as the vegetation which it supports; it has not been formed simultaneously with the rock on which it rests, or with the bed of sand which it covers.

This important observation is commonly overlooked. Accustomed to see the same flowers re-appear at each return of spring, the same meadows clothed again in fresh verdure, we scarcely

• Of all the branches of Natural History, undoubtedly Botany is that which has hitherto (mineralogy and geology now dividing with it the public attention), in Britain, been the most generally cultivated: hence every where we find splendid gardens and conservatories; and numerous works on botany are daily issuing from the press. Distinguished botanists have not been wanting in England: and Scotland, although behind in this science, has given to England several young, intelligent, and active botanists,—to Europe its greatest botanist, our illustrious countryman Brown: but, strange to say, the only naturalists who have actively embarked in the botany of Scotland, have been principally Englishmen or foreigners. Scotland offers still a fine and unexplored field to the philosophic botanist,—in the investigation of the physical and geographical distribution of its land and aquatic plants. He who shall undertake this highly interesting investigation, must be intimately acquainted with the facts and reasonings of meteorology and hydrography,with the details and views of geology; and the ardent inquirer into the geography of plants cannot expect to illustrate it, without also knowing the natural history of animals; and, finally, he must be familiar with the use of the barometer, and other instruments.-EDIT.

reflect upon the origin of this beautiful and abundant vegetation, or rather referring it to the period of the general creation of beings, it seems to us to lose itself in the mysterious obscurity of the formation of the universe; and we thus find ourselves discharged, as it were, from the task of inquiring, by what means nature has everywhere diffused this precious mould, the source of riches and of life, and which yet is but the residue of generations heaped upon generations. Here an objection presents itself, which appears, in part, to destroy what I have advanced. If vegetable earth, it may be said, is necessary to the existence of plants, it must have been created previously to their existence, and can only receive what it had itself furnished them.

Such has been the error, which, during a long series of ages, has prevented our understanding one of the greatest operations of nature, and which, although continually before our eyes, has only escaped our observation from the little attention which we have bestowed upon an order of plants considered as little worthy of regard from their homeliness of aspect, their diminutive size, and the simplicity of their composition; but when the piercing eye of genius determined their relations in the natural order of things, when it recognised the functions which they had to fulfil, and the rank which they occupy in the general system of vegetation, they assumed a character of grandeur, which directed the attention toward their existence. It has been discovered, that, so far from requiring vegetable earth for their subsistence, they have furnished it by their decomposition, in small quantity it is true, but yet sufficient for the reception of plants of an order somewhat higher, and to which, in proportion as the vegetable earth increases, succeed vegetables much more vigorous.

To explain what we have to say upon this subject, we must fix our notice, for a moment, upon those plants which I have said to be the basis of vegetation. Although very common throughout nature, they have scarcely been remarked. They everywhere invest walls, rocks, humid places, and the trunks of trees; they attach themselves to all substances, however little they may be favoured by circumstances. The rays of the sun, and dry and cold winds, are as much inimical to them, as shade and humidity are favourable. These plants bear the names of conferva, byssi, and lichens. To them succeed mosses, hepatica, lycopoOCTOBER-DECEMBER 1826.

E

diacea, fungi, &c. They constitute a great and important family in the natural order of vegetation. Linnæus has named them cryptogamous plants, from the circumstance that the mode of fecundation, by which they are reproduced, is very little

known.

The byssi are plants which present themselves only under the form of a powdery tissue, or of a filamentous down, variously coloured; they attach themselves chiefly to moist substances, dry up in the rays of an ardent sun, and leave behind them only formless and blackish spots. The conferva belong to stagnant waters and inundated lands; they are composed of capillary elongated filaments, simple or articulated. The lichens are sometimes nothing else than prominent blackish points, scattered upon a greenish or greyish ground; at other times they are simple or branched lines, which have the semblance either of alphabetical characters, or of a sort of geographical chart, marked upon a very thin smooth membrane, applied to the bark of trees. Other species attach themselves to rocks, forming plats of various colours, leprous, granular, or powdery crusts; or assuming a greater degree of development, spread out into rosaceous expansions of a foliaceous aspect, with laciniated or lobated margins. Some of them rise from a scaly crust, in the form of simple stems, or ramify into small elegant shrubs, dilated at their summits into little cups, which are either simple or proliferous, and which are furnished upon their edges with fungous tubercles, of a brown or blackish colour, or of a beautiful scarlet red. Others present themselves under a very different form, falling from the trees in long intermingled filaments, like horse's hair or tufted locks; some of a greyish green, others of a beautiful gold yellow, orange or lemon. I shall not extend my remarks upon this class of plants, with which we shall have to form an acquaintance in another place, when we come to treat of the natural families. Here we shall speak of them only with relation to the great functions which nature has confided to them for the establishment of vegetation.

When we remark the hardness, the dryness, and the bareness of rocks, we should scarcely imagine that their summit might one day be crowned with forests; and yet this great work is carried on every day under our eyes, and even in the midst of our