Two systems at the present day divide the botanical world between them, the artificial one of Linnaeus, and the natural one ofJussieu. Yet it can be only those who are very unphilosophical, or ignorant of the subject, or who have some sinister purpose to serve, who bring- these sys tems into competition as rivals. They are in fact allies and mutual supports, and it is the opinion of an experienced bota nist (Dr. Smith) of the present day, that in the actual state of the science, perhaps neither of these systems can stand alone. Plants are so numerous, and those of their parts upon which all systems depend so liable to variations and irregularities, that neither the Linnxan system, nor any other artificial one, however simple and com prehensive its principles, can conform to them all with sufficient precision to be in any degree infallible. On the other hand, every natural system is necessaril3 so in complete, for want of an uniformly per fect knowledge in its contriver of all the plants in the world, and of their mutual dependencies on each other, as well as of the best possible manner of defining and characterizing the classes and orders in which human contrivance is obliged to dispose them, that to use such a system, for the investigation of plants, is like learning to read by the Chinese character. But if we use these two methods in conjunction, they eminently assist each other. If a new plant cannot be made out but by artificial marks, its affinity may" be guessed at in the natural system. We shall now proceed to give an outline of both systems, that the student may un derstand their principles, and comprc. bend their several advantages.
The Linnman system is founded on the number, situation, and proportion of the essential organs of impregnation, termed stamens and pistils, whose uses and struc ture we have sufficiently explained. Tha classes, which are 24, principally owe their distinctions to the stamens ; the or ders, or subdivisions of the classes, are generally marked by the number of the pistils, or by some other circumstances equally intelligible. The names of both are of Greek derivation, and allude to the functions of the respective organs. The first eleven classes are distinguished sole.. ly by the number of the stamens.
I. Monandria. Stamen 1. From povoy, one, and a man. A small class con sisting of only two orders.
1. Monogynia. Style 1. From ft-sttn, one, and a woman. Instances of this are, Canna, Alpinia, Lopezia, Ilippu ris.
2. Digynia, Styles 2. eLG, two, and yyrn, Corispermum, Blitum.
II. Diandria. Stamens 2.
1. Monogynia, Jasminum, Salvia, Ve ronica.
2. Digynia. Anthoxanthum only, kind of grass.
3 .Trigynia. Piper only, or pepper. Tricazdria. Stamens 3.
1. Monogynia. Valeriana, Iris, Cype. rus, Scirpus.
2. Digynia. Contains almost all the natural orders of true grasses.
3. Trigynia. Holosteum, Montia, Po lycarpon.
IV. Tetrandria. Stamens 4.
1. Monogynia. Protea, Scabiosa, Plan
tago, Galium.
2. Digynia. Buffonia.
3. Tetragynia. Potamogeton, Ruppia.
V. Pentandria. Stamens 5. One of the largest classes.
1. Monogynia. Borago, Echium, Pri mula, and some genera removed hither from the 19th class, to be mentioned • hereafter, as Viola, Jasione, Ste.
2. Digynia. Chenopodium, Ulmus, Gen tiana. Then follow the whole natural order of Umbelliferx, of which Daucus, Angelica, Cicuta, and Apium, are exam ples.
3. Trigynia. Viburnum, Sambucus.
4. Tetragynia. Parnassia.
5. Pentagynia. Statice and Linum.
6. Polygynia. Myosurus only. VI.Ilexandria. Stamens 6.
1. Monogynia. Liliuin, and others of its natural order, thence called Liliace : a tribe considered by Linnxus as the noblest of the vegetable kingdom ; an idea supposed to allude not merely to their beauty and splendour, but also the text, "Consider the lilies of the field, how they grow, they toil not, neither do they spin. ' 2. Digynia. Oryza and Galmia, grass es with 6 stamens.
3. Trigynia. Colchicum, S cheuchzeria,the latter lately discovered to be a British genus, by the Rev. Mr. Dalton, of Yorkshire.
4. Tetragynia. Petiveria only.
5. Hexagynia. Wendlandia and Da masoniutn of Schreber.
6. Polygynia. Alisma only.
VB. Heptandria. Stamens 7.
1. Monogynia, Trientalis, and .zEsculus.
2. Digynia. Limeum.
3. Tetragynia. Saururus.
4. Heptagynia. Septas.
VIII. Octandria. Stamens 8.Viii. Octandria. Stamens 8.
1. Monogynia. A large and beautiful order, containing Epilobium, Fuchsia, Vaccium, and the vast genus Erica : also, according to Dr. Smith, Acer.
2. Digynia. Mxhringia, &c.
3. Trigynia. Polygonum, &c.
4. Tctragynia. Adoxa, Paris.
IX. Enneandria. Stamens 9.
1. Monogynia. Laurus, famous for producing the cinnamon, sassafras, and camphor.
2. Trigynea. Rheum, the rhubarb only.
3. Hexagynea. Butornus.
X. Decandria. Stamens 10. A rather numerous class.
1. Monogynia. Cassia, and some other papilionaceous plants. Also Ruta and its family, followed by Kalmia, Rhododen dron, Andromeda, &c.
2. Digynia. Saxifraga, Dianthus, Sa p onaria.
3. Trigynia. Silene and Arenaria, both allied to Dianthus ; also Malpighia and Bannisteria.
4. Pentagynia. Lychnis, Cerastium, and Spergula ; allied also to the Dianthus. Cotyledon, Sedum, and Oxalis follow.
5. Decagynia. Neurada and Phytolae ca.
XI. Dodecandria. Stamens 12-19. 1.11onogynia. Lythrum, Halesix, Pe ganum.
2. Digynia. Agrimonia.
3. Trigynia. Reseda and Euphorbia.
4. Tetragynia. Has been recently established to receive Calligonum and Apoilsgeton.
5. Pentagynia. Glinus.
6. Dodecagynia. Sempervivum, the house-leek.
Thus far the Linnxan classes are found ed solely upon the number ofthe stamens. In the following ones, insertion, propor tion, and connection of the same parts are to he considered. Of all the preced ing classes, the characters of the 4th, 6th, and 10th, chiefly interfere with any ofthe subsequent ones, as will be ex plained hereafter.