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.
Robert Brown's literary efforts were limited to these monographs; he nowhere attempted to give a connected account of the principles which he follows in them, an exposition of his morphology or a theory of classification, nor did he frame a new system. The results of his studies which were really fruitful and served to advance the science are to be found in the more general remarks, which he managed to insert quite incidentally in his monographs. In this way he succeeded in clearing up the morphology of the flower and with it the systematic position of some difficult families of plants, such as the Grasses, Orchids, Asclepiads, the newly-discovered Rafflesiaceae and others, and to throw new light at the same time on wider portions of the system; in his considerations on the structure and affinities of the most remarkable plants, which had been collected in Africa by different travellers in the years immediately following 1820, he discussed difficult and remarkable morphological relations in the structure of the flower. He referred especially in this essay (1826) to the relations between the numbers of the stamens and carpels, and those of the floral envelopes in the Monocotyledons and Dicotyledons, and showed how these typical, or as he calls them in De Candolle's phraseology, symmetrical relations were changed by abortion, while he entered at the same time into a more exact determination of the position of the aborted and of the perfect organs, in order to discover new relations of affinity.
