But before the examination of the Algae, and soon after of the Fungi also, led to such great results, the systematic botany of the higher plants underwent important changes through the methodical study of the embryology of the Muscineae and Vascular Cryptogams. These groups had been frequently and carefully examined by good observers since the last century, and the systematists, without penetrating deeply into the peculiarities of their organisation, had brought the species and genera, the families and even the higher divisions into tolerable order. Comprehensive and methodically arranged catalogues of these plants had been formed, and attempts had been made to explain their morphology by that of the Phanerogams; Schmidel[53] published valuable observations on the Liverworts in the year 1750, Hedwig especially on the Mosses in 1782; these works were followed by Mirbel’s thorough examination of Marchantia in 1835, by Bischoff’s of Marchantieae and Riccieae, by Schimper’s study of the Mosses in 1850, and by Lantzius Beninga’s[54] contributions to the knowledge of the structure of the moss-capsule in 1847. The organisation, and to some extent the germination, of the Vascular Cryptogams had become better known since 1828 through Bischoff’s[55] researches; Unger had as early as 1837 described the spermatozoids in the antheridia of various Mosses, Nägeli had discovered them on an organ of the Ferns which had up to that time been taken for the cotyledonary leaf of these plants, and on the same part of the plant Suminski in 1848 observed the female sexual organs and the entrance of the spermatozoids into them. The history of the germination of the Rhizocarps, from which Schleiden thought that he had proved his erroneous theory of fertilisation with more than usual certainty, had been examined some years before by Nägeli, and also by Mettenius, in great detail; here too Nägeli detected the spermatozoids. Thus important fragments of the life and organisation of these plants had been described up to the year 1848, but until they were more fully understood and connected together they had but little scientific value, the one fact perhaps excepted, that fertilisation in the Cryptogams as in animals was effected by spermatozoids. A perfect insight into the embryological conditions in question could only be obtained when the embryology of the Phanerogams especially had been cleared up, for according to Schleiden’s theory, which made the pollen-tube enter the embryo-sac in the ovule and develop into the embryo, the ovule was no longer to be regarded as a female sexual organ, but only as a place of incubation for the embryo, which was thus really produced asexually. This important question was set at rest by WILHELM HOFMEISTER’S work, ‘Die Entstehung des Embryos der Phanerogamen,’ which appeared in 1849. In this work, and in a series of subsequent treatises, he showed that the egg-cell is formed in the embryo-sac before fertilisation, and that