Four stamens of different length, two long and two short Six 66 four long and two short III. Stamens and pistils in the same or in different flowers, on the same or on different plants B. FLOWERS ABSENT TABULAR VIEW OF CLASSES AND ORDERS. 10. Decandria. "11. Dodecandria. "12. Icosandria. 13. Polandria. 14. Didynamia. "15. Tetradynamia. 16. Monadelphia. "17. Diadelphia. "18. Polyadelphia. "19. Syngenesia. “20. Gynandria. "21. Monoecia. 22. Dioecia. 23. Polygamia. 24. Cryptogamia. Tabular View of Classes and Orders--continued. Classes. Orders. Pentandria ......... five stamens Enneandria......... nine do. Decandria ........ten do. Dodecandria ..twelve do. Polyandria ......... many do. Pentandria......... five stamens (two above and three below.) Hexandria ......... six do. (three right, three left, or three above and three below.) Octandria...........eight do. (four above and four below, all united at the base.) Decandria............ten do. (one above and nine below, united in a cleft surrounding the ovary.) Pentandria......... five stamens Examples. Erodium. Geranium. Malva. Fumaria. Polygala. Pisum, Trifolum, Genista. Hypericum. Polygamia segregata, a common Echinops. calyx including all the florets, and a distinct calyx for each. Monogamia ...... Diandria ........ ..two anthers Triandria Orchis. .three do. Decandria...........ten do. 113. The artificial system possesses the great advantage of clear, simple characteristics, by which it is generally easy to ascertain the class and order of a plant. It may be recommended to beginners as an introduction to the natural system. Classes. I. Acotyledones...... II. Monocotyledones III. Dicotyledones. NATURAL SYSTEM (JUSSIEU'S). Monoclines, flowers Monohypogynæ (stamens hypogynous).. (Epistamineæ (stamens epigynous). Apetala (no petals) Peristamine (stamens perigynous).. Hypostamineæ (stamens hypogynous)... Monopetala (petals Pericorolla (corolla perigynous).... Epicorolla (corol- Synanthera (anthers united) distinct). ......... 114. It may be observed that this system, being founded partly on individual organs, is also, in some degree artificial. Rigid, precisely scientific distinctions, are not found in Nature, which seems to prefer gradual or almost imperceptible transitions from the simplest to the most complex of her developments. IV. DESCRIPTION OF PLANTS. DESCRIPTIVE BOTANY. 115. The marvellous variety, both in form and organisation, of the subjects of the vegetable kingdom may be inferred from the fact, that already above 100,000 plants have been observed; and every day increases the vast amount. These, however, occupy the surface of the whole earth; only a small proportion of the whole is produced in any given country. In Germany there are probably about 7,000. In the British isles a much smaller number. The description of plants is to be found in works exclusively appropriated to botanical science. These works either comprehend all plants, or those of a greater or less extent of territory, or only of a district. Those devoted to the universal Flora are generally composed in Latin, which is a language more universally understood than any other. In reference to the Flora of Germany, which has been often written, we, out of the many works on this subject, mention only Koch's Synopsis of the German and Swiss Flora, and the compendium of the German Flora by the same author, and the work of Kittel. Also the following descriptive local Floras, for example, that of Frankfort-on-the-Maine, by Fresenius; of Baden, by Gmelin; of Würtemberg, by Schübler; and also Marten's Flora of the same place; of Hesse, by Schnittspahn; Flora of the Rhine, by Döll; Austria, by Schultes; Silesia, by Wimmer; Berlin, by Schlectendal; the Prussian Flora, by Ruthe; Brunswick, by Lachmann, &c. Besides the English Flora by Sir J. E. Smith, which will always be regarded as the standard of descriptive British botany, and the works of Balfour, Babbington, Irvine, and others, the following local Floras are recommended: Dr. Johnston's Flora of Berwick-on-Tweed, Leighton's Flora of Shropshire, Jones's of Devon, Murray's Northern Flora, unfortunately only a fragment, but a valuable relic, especially to such as knew the amiable author, who was prematurely cut off in the zealous discharge of the duties of his profession. Besides these, there are various county catalogues of plants, more or less complete, and the ancient local lists of Blackstone, Jacobs, Warner, &c., together with the interesting itineraries of Johnson, the precursor of all British local botanists. [As regards American plants, the principal authorities are Bigelow, U. P. C. Barton, Darlington, Rafinesque, &c. Gray's Botanical Text-Book may be recommended as a standard and valuable work.] Some work of this nature, in which the plants are described and arranged either on the artificial or on the natural system, is indispensable to the student of botany, in order to enable him to identify the plants which he may collect, by comparing them with those described in books. The only method of learning botany is by collection, comparison, discrimination, and identifi |