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 Rh tube, and during Griffith's time the papers of Schleiden, which extended the comparative study of the ovule and advanced the important though erroneous view that the embryo originated inside the embryo-sac from the tip of the entering pollen tube, were appearing. Schleiden's text-book did not appear until too late to be known to Griffith. His interest was keen on continuing the work, that Brown had begun, on plants that only a resident in the tropics had the opportunity of studying properly, and the first volume of the Notulae, with the accompanying Icones, and the more systematic volume on the Monocotyledons and Dicotyledons contain his unpublished observations on the ovule and flowers of many plants.

His first paper in the Linnean Transactions was on the ovule of Santalum. Griffith observed and rightly interpreted the free prolongation of the embryo-sac from the nucellus, and described the application of the pollen tube to the summit of the embryo-sac, the development of the endosperm, and the origin and development of the embryo. He also recognised and figured the great prolongation backwards of the embryo-sac as an empty, absorbent caecum. At first he left the origin of the embryo doubtful, while recognising the advantages of the exposed embryo-sac for settling the question, but later he decided in favour of Schleiden's erroneous view that the embryo developed from the tip of the pollen tube. Griffith also examined the ovules of Osyris recognising the corresponding facts.

Comparison with the figures of Santalaceous ovules in Guignard's later work will serve to show both the magnificent accuracy in observation of Griffith and the limitation, running through all the work of the time, of not recognising the contents of the embryo-sac before fertilisation.

The Loranthaceae was another family on which the development of the embryo-sac and the processes of fertilisation and development of the fruit interested Griffith specially. Not only did he send his results home to the Linnean Society in two papers, but his descriptions and figures of all the species described in the Notulae take account of these morphological and developmental facts. He traced the development of the cavity of the ovary and regarded the ovules as reduced to their