. The cell; outlines of general anatomy and physiology. om the egg-nucleus,and the other from the sperm-nucleus. 2. The Fertilisation of Phanero-gamia. The discoveries which have beenmade concerning the processes of fertilisa-tion in Phaneiogamia correspond mostcompletely with those which have been ob-served in the animal kingdom. Stras-burger (VII. 38) and Guignard (VII. 15)stand in the first rank of most suitable objects for examinationare the Liliaceae, especially Lilium martagonand Fritillaria imperialis. One of the cells,into which the pollen grain divides inPhanerogams,
. The cell; outlines of general anatomy and physiology. om the egg-nucleus,and the other from the sperm-nucleus. 2. The Fertilisation of Phanero-gamia. The discoveries which have beenmade concerning the processes of fertilisa-tion in Phaneiogamia correspond mostcompletely with those which have been ob-served in the animal kingdom. Stras-burger (VII. 38) and Guignard (VII. 15)stand in the first rank of most suitable objects for examinationare the Liliaceae, especially Lilium martagonand Fritillaria imperialis. One of the cells,into which the pollen grain divides inPhanerogams, corresponds to the sperma-tozoon, whilst the vegetable egg-cell, whichin the ovule is enclosed in the ovary of thegyncecium, forms the most important por-tion of the embryo-sac, and corresponds tothe animal egg. When the pollen grain has reached thestigma of the style, its contents commenceto emerge through a weakened portion ofthe membrane, and to develop into a longtube (Fig. 143), which penetrates into thestyle until it reaches an embryo-sac. Here. —Section throughthe embryo-sac of Liliummartagon (after GuignardXV., Fig. 75). At the end ofthe , whose weak-ened wall is allowing itscontents to eccape, thesperm-nucleus may be seenwith its two egg-nucleus is also pro-vided with two the right, at the end ofthe pollen tube, a synergidamay be distinguished whichhas commenced to disinte-grate. 264 THE CELL it presses between the two synergidae right into the pollen grain and the pollen tube contain two nuclei, thevegetative one, which takes no part in fertilisation, and the sperm-nucleus. This latter comes to lie at the end of the pollen tube,after this has made its way to the egg-cell; thence it passesthrough the weakened cellulose wall into the protoplasm of theegg, whilst two centrosomes advance in front of it; these latterwere discovered by the French investigator, Guignard (Fig. 143).It soon meets the egg-nucleus
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