. Botanisk tidsskrift. Botany; Plants; Plants. — 163 — Very extraordinary complications appear, when both a typical and aposporic ES are developed in the same ovule. A number of such stages are shown in fig. XI. tn fig. A there are two ES, of which the left one has already developed endosperm and embryo, the one on the right is probaby the typical ES which has not developed further, as no fertilization has taken place. The apo- sporic ES has already removed the possibility of fertilization, in filling up the entrance to the typical egg cell. In fig. B an apparently later stage is repre- sented
. Botanisk tidsskrift. Botany; Plants; Plants. — 163 — Very extraordinary complications appear, when both a typical and aposporic ES are developed in the same ovule. A number of such stages are shown in fig. XI. tn fig. A there are two ES, of which the left one has already developed endosperm and embryo, the one on the right is probaby the typical ES which has not developed further, as no fertilization has taken place. The apo- sporic ES has already removed the possibility of fertilization, in filling up the entrance to the typical egg cell. In fig. B an apparently later stage is repre- sented. The typical ES is quite enclosed in the endosperm of the aposporic ES. One can still observe the egg cell and two polar nuclei. The case in fig. XI C is really most curi- ous, where two ES appear, both with endo- sperm and embryo. Perhaps one is a typical one which has been fertilized and the other an aposporic one which has grown round the other. Very often one meets ovules with two ES of a significantly different stage of development. In the farther one the egg cell is still undi- vided, whilst the one behind seems to consist only of endosperm cells. I have never been able to find embryo in such cases. It seems to me that this is the final stage of the case depicted in fig. 28, in which the lower ES was typical and the one behind aposporic with eight dividing nuclei. Fig. XIII represents a peculiar case where the embryo of the aposporic embryo sac is istuated in the antipodal region and perhaps originates from an antipodal Fig. XIII II. flagellare, aposporic embryo sac with an embryo, E, at the antipodal end, A ; M, the mikropyle with the rests of the typical ES ; S, synergids; C, endo- sperm nucleus. Results. The preceding statements show that a remarkable variation as regards the embryo formation is to be found in the group Pilo- sella of the genus Hieracium. In H. auricula (as in H. venosum of the Stenotheca-group) the embryo sac formation is quite normal and
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