. Botanisk tidsskrift. Botany; Plants; Plants. — 162 — However most of the ES are of aposporic origin, especially in H. flagellar-e, where consequently the egg cell has the unreduced number of chromosomes. It is not necessary for such an egg to be fertilized, but it continues directly the embryo formation as in other apogamic species. In ordinary cases therefore in Hieracium a normal seed is developed where, however, the embryo and endo- sperm are of vegetative A B Fig. XII. H. excellens; A, ovule with one aposporic and under this one typical embryo sac; B, the typical embryo sac encl
. Botanisk tidsskrift. Botany; Plants; Plants. — 162 — However most of the ES are of aposporic origin, especially in H. flagellar-e, where consequently the egg cell has the unreduced number of chromosomes. It is not necessary for such an egg to be fertilized, but it continues directly the embryo formation as in other apogamic species. In ordinary cases therefore in Hieracium a normal seed is developed where, however, the embryo and endo- sperm are of vegetative A B Fig. XII. H. excellens; A, ovule with one aposporic and under this one typical embryo sac; B, the typical embryo sac enclosed in the endosperm of the aposporic one. Fig. X shows a remarkable anomaly which is quite often met with. There are two embryos in the same ES. The adventive embryo is, however, in this case not of the same value as for instance in the ordinary „Nucellarsprossungen" in several plants, but its origin is an endosperm cell which is shown in fig. X, B. It may possibly depend upon the fact that the polar nuclei have not become united, and the one of them is the cause of the embryo formation. I have not yet determined the number of chromosomes in the cells of such embryos which must be 68, if the polar nuclei have been Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Botaniske forening i København. København : H. Hagerups Forlag
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Keywords: ., bookcentury1800, bookdecade, booksubjectbotany, booksubjectplants
