ACOTYLEDONES, the name given by Antoine Laurent de Jussieu in 1789 to the lowest class in his Natural System of Botany, embracing flowerless plants, such as ferns, lycopods, horse-tails, mosses, liverworts, sea-weeds, lichens and fungi.
In interpreting its environment first as a world of things that seem to stand in a relation of exclusion to one another and to itself, then as a natural system governed by rigid mechanical necessity, the mind can yet feel that in its very opposition the world is akin to it, bone of its bone and flesh of its flesh.
The family Araucarieae, represented by Araucaria and Agathis, should perhaps be separated as a special class and a rearrangement of other genera more in accord with a natural system of classification will soon be possible; but for the present its twofold subdivision may be retained.
Robert Brown (1773-1858) was the first British botanist to support and advocate the natural system of classification.
It contains all the best land in Berar; it is full of deep, rich, black alluvial soil, of almost inexhaustible fertility, and it undulates sufficiently to maintain a natural system of drainage, but there is nothing picturesque about this broad strip of champaign country.
Besides those already mentioned, his works include An Outline of the First Principles of Horticulture (1832), An Outline of the Structure and Physiology of Plants (1832), A Natural System of Botany (1836), The Fossil Flora of Great Britain (with William Hutton, 1831-1837), Flora Medica (1838), Theory of Horticulture (1840), The Vegetable Kingdom (1846), Folia Orchidacea (1852), Descriptive Botany (1858).
That he anticipated in any manner the inductive philosophy cannot be contended; his botanical studies did not lead him, like his contemporary Konrad von Gesner, to any idea of a natural system of classification, and he rejected with the utmost arrogance and violence of language the discoveries of Copernicus.
A natural system must take into account the nature of the larva and of the metamorphosis in conjunction with the general characters of the imago.
Some account of the history of plant classification and the development of a natural system in which an attempt is made to show the actual relationships of plants, is given in the article BOTANY.
Though best known for his artificial (or sexual) system, Linnaeus was impressed with the importance of elaborating a natural system of arrangement in which plants should be arranged according to their true affinities.