The ovulum has, according to him, but one covering, which in the ripe seed he calls episperm.

He considers the centre of the hilum as the base, and the chalaza, where it exists, as the natural apex of the seed.
M.Mirbel, in 1815, though admitting the existence of the foramen or micropyle of the testa,* describes the ovulum as receiving by the hilum both nourishing and fecundating vessels,** and as consisting of a uniform parenchyma, in which the embryo appears at first a minute point, gradually converting more or less of the surrounding tissue into its own substance; the coats and albumen of the seed being formed of that portion which remains.*** (*Footnote.

Elem.

de Physiol.Veg.et de Bot.

tome 1 page 49.) (**Footnote.