Fig. 23. (Utricularia vulgaris.) Longitudinal section through a young bladder, 1/100 of an inch in length, with the orifice too widely open.

The accompanying figure (fig. 23) shows a section, which happened to be strictly medial, through the footstalk and between the nascent antennae of a bladder of Utricularia vulgaris, 1/100 inch in diameter.  The specimen was soft, and the young valve became separated from the collar to a greater degree than is natural, and is thus represented.  We here clearly see that the valve and collar are infolded prolongations of the walls of the bladder.  Even at this early age, glands could be detected on the valve.  The state of the quadrifid processes will presently be described.  The antennae at this period consist of minute cellular projections (not shown in the above figure, as they do not lie in the medial plane), which soon bear incipient bristles.  In five instances the young antennae were not of quite equal length; and this fact is intelligible if I am right in believing that they represent two divisions of the leaf, rising from the end of the bladder; for, with the true leaves, whilst very young, the divisions are never, as far as I have seen, strictly opposite; they [page 426] must therefore be developed one after the other, and so it would be with the two antennae.

At a much earlier age, when the half formed bladders are only 1/300 inch (.0846 mm.) in diameter or a little more, they present a totally different appearance.  One is represented on the left side of the accompanying drawing (fig. 24).  The young leaves

Fig. 24. (Utricularia vulgaris.) Young leaf from a winter bud, showing on the left side a bladder in its earliest stage of development.

at this age have broad flattened segments, with their future divisions represented by prominences, one of which is shown on the right side.  Now, in a large number of specimens examined by my son, the young bladders appeared as if formed by the oblique folding over of the apex and of one margin with a prominence, against the opposite margin.  The circular hollow between the infolded apex and infolded prominence apparently contracts into the narrow orifice, wherein the valve and collar will be developed; the bladder itself being formed by the confluence of the opposed [page 427] margins of the rest of the leaf.  But strong objections may be urged against this view, for we must in this case suppose that the valve and collar are developed asymmetrically from the sides of the apex and prominence.  Moreover, the bundles of vascular tissue have to be formed in lines quite irrespective of the original form of the leaf.  Until gradations can be shown to exist between this the earliest state and a young yet perfect bladder, the case must be left doubtful.