1. Exogens or Dicotyledons. A. With calyx and corolla: Thalamiflorals (polypetalous hypogynous), Calyciflorals (polypetalous perigynous), Corolliflorals (gamopetalous). B. Monochlamydeous plants (with a single floral envelope). 2. Endogens or Monocotyledons. A. Phanerogams (true Monocotyledons), B. Cryptogams (vascular Cryptogams including Naiadeae). II. Cellular plants or Acotyledons. A. With leaves (Muscineae), B. Without leaves (Thallophytes). The number of families, with Linnaeus 67, with A. L. de Jussieu 100, was increased by De Candolle to 161. If the principles of comparative morphology laid down by De Candolle were at first prevented from being rapidly disseminated in Germany by the philosophical tendencies then reigning among its botanists, and especially by the obscurities of Goethe’s doctrine of metamorphosis, yet these principles and his views also on the natural system won their way by degrees to acknowledgment and acceptance; and after the year 1830 the study of the system was prosecuted by the botanists of Germany, as well as by those of England and France, as the proper object of the science. We may even say that the impulse given by De Candolle worked more powerfully from that time forward in Germany than in France. It may be said too of De Candolle’s contemporary, the Englishman ROBERT BROWN[38] (1773-1858), whose chief labours fall in the period between 1820 and 1840, that he, like De Candolle, was better appreciated during that time in Germany than in any other country. Robert Brown, who spent the five years from 1801 to 1805 in Australia, studied the flora of that quarter of the world, and discussed in numerous essays the botanical results of various journeys made by other naturalists in polar regions and in the tropics. In this way he found opportunity to leaven the ideas, which through Humboldt’s influence had become predominant respecting the geography of plants, with the spirit of the natural system; he also made the morphology and systematic position of a number of families the subject of critical investigation.