se is an admirable plant for the study of the
development of the flower which is much the same in other
angiosperms. To study this, it is only necessary to teaze out, in a
drop of water, the tip of a raceme, and putting on a cover glass,
examine with a power of from fifty to a hundred diameters. In the
older stages it is best to treat with potash, which will render the
young flowers quite transparent. The young flower (Fig. 95, _A_) is
at first a little protuberance composed of perfectly similar small
cells filled with dense protoplasm. The first of the floral leaves
to appear are the sepals which very early arise as four little buds
surrounding the young flower axis (Fig. 95, _A_, _B_). The stamens
(_C_, _an._) next appear, being at first entirely similar to the
young sepals. The petals do not appear until the other parts of the
flower have reached some size, and the first tracheary tissue
appears in the fibro-vascular bundle of the flower stalk (_D_). The
carpels are more or less united from the first, and form at first a
sort of shallow cup with the edges turned in (_D_, _gy._). This cup
rapidly elongates, and the cavity enlarges, becoming completely
closed at the top where the short style and stigma develop. The
ovules arise in two lines on the inner face of each carpel, and the
tissue which bears them (placenta) grows out into the cavity of the
ovary until the two placentae meet in the middle and form a partition
completely across the ovary (Fig. 95, _H_).

The stamens soon show the differentiation into filament and anther,
but the former remains very short until immediately before the
flowers are ready to open. The anther develops four sporangia
(pollen sacs), the process being very similar to that in such
pteridophytes as the club mosses. Each sporangium (Fig. _E_, _F_)
contains a central mass of spore mother cells, and a wall of three
layers of cells. The spore mother cells finally separate, and the
inner layer of the wall cells becomes absorbed much as we saw in
the fern, and the mass of mother cells thus floats free in the
cavity of the sporangium. Each one now divides in precisely the same
way as in the ferns and gymnosperms, into four pollen spores. The
anther opens as described for _Erythronium_.

By carefully picking to pieces the young ovaries, ovules in all
stages of development may be found, and on account of their small
size an