As the quadrifid and bifid processes offer one of the greatest peculiarities in the genus, I carefully observed their development in Utricularia neglecta.  In bladders about 1/100 of an inch in diameter, the inner surface is studded with papillae, rising from small cells at the junctions of the larger ones.  These papillae consist of a delicate conical protuberance, which narrows into a very short footstalk, surmounted by two minute cells.  They thus occupy the same relative position, and closely resemble, except in being smaller and rather more prominent, the papillae on the outside of the bladders, and on the surfaces of the leaves.  The two terminal cells of the papillae first become much elongated in a line parallel to the inner surface of the bladder.  Next, each is divided by a longitudinal partition.  Soon the two half-cells thus formed separate from one another; and we now have four cells or an incipient quadrifid process.  As there is not space for the two new cells to increase in breadth in their original plane, the one slides partly under the other.  Their manner of growth now changes, and their outer sides, instead of their apices, continue to grow.  The two lower cells, which have slid partly beneath the two upper ones, form the longer and more upright pair of processes; whilst the two upper cells form the shorter [page 428] and more horizontal pair; the four together forming a perfect quadrifid.  A trace of the primary division between the two cells on the summits of the papillae can still be seen between the bases of the longer processes.  The development of the quadrifids is very liable to be arrested.  I have seen a bladder 1/50 of an inch in length including only primordial papillae; and another bladder, about half its full size, with the quadrifids in an early stage of development.

As far as I could make out, the bifid processes are developed in the same manner as the quadrifids, excepting that the two primary terminal cells never become divided, and only increase in length.  The glands on the valve and collar appear at so early an age that I could not trace their development; but we may reasonably suspect that they are developed from papillae like those on the outside of the bladder, but with their terminal cells not divided into two.  The two segments forming the pedicels of the glands probably answer to the conical protuberance and short footstalk of the quadrifid and bifid processes.  I am strengthened in the belief that the glands are developed from papillae like those on the outside of the bladders, from the fact that in Utricularia amethystina the glands extend along the whole ventral surface of the bladder close to the footstalk.

[Utricularia vulgaris.