Page:Popular Science Monthly Volume 84.djvu/169

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PSM V84 D169 Double apples section.jpg

Double Apples. Section about two thirds natural size.

that of the polyembryonic seeds already noted, perhaps by a sort of fasciation or doubling of the ovule and the production in it of two distinct egg cells.

The seeds of the Mcintosh apple appear, indeed, to abound in anomalous forms. Another seed in the same abnormally colored apple was remarkable for its small size, being perfectly formed, but of scarcely one fourth the length of an ordinary seed. Other seeds of this variety have been found in which the seed coat failed to develop and the embryo grew to full size without the usual brown covering, traces of which were found as a small patch at the hilum. An instance of this kind has also been noted in a seed of the Rhode Island Greening. In other cases the seed coats have split open as the seed developed, apparently as the result of the excessive production of endosperm which protruded as an irregular whitish mass containing the embryo. Though it is possible that such forms are the result of some unnatural state of nutrition in the seeds of this variety, nothing is known of the conditions which give rise to their production. Owing to the comparatively infrequent occurrence of abnormal forms, an investigation of their underlying causes is more difficult than the study of normal variation and progress is consequently slower.