278 
SVEDELIUS : LIFE-HISTORY OF 
The ovules are anatropous (fig. 7) with two integuments. 
The ovarial cavities, but not the air-chambers formed by the 
split plaeentæ, are quite filled up with mucilage before 
fertilization and during the early stages of the embryo- 
development (fig. 6). It is a secretion from the outermost 
celhlayer of the wall of the ovarial cavities, the cells of 
which are rather large and high (PL. XXIV., A, fig. 22). The 
nucleus is always situated at the inside wall of the cell. 
The layer that secretes the mucilage just inside is rich in 
starch, contrary to the condition in the other tissues of the 
ovary. The external cells bordering on the air-chambers do 
not differ from the others in the tissue of the fruit, nor do 
they form any mucilage. 
The mucilage is deeply stained by fuchsin, methyl violet, 
methyl green, and gentian violet, but not by Congo red. 
Iodine in potassium iodide and iodine-zinc-chloride only 
cause a feeble yellowish stain. Thus it appears that the 
mucilage is a pectin-mucilage, like most mucilages which 
swell in water. 
It is evident that the occurrence of starch in the outside 
cells of the plaeentæ may be in some relation to the secre¬ 
tion of the mucilage. That starch is used to form mucilage 
by plants has been especially observed in seeds, e. g ., in 
the Cistaceæ the seeds produce mucilage, the formation 
of which has been studied by Rosenberg (24). In the outer 
coats of the seeds, especially in species with abundant 
mucilage formation, there is often much starch in the 
epidermal cells which cannot be used for the embryo but 
apparently is in connection with the mucilage-formation, so 
that it is partly employed for the formation of mucilage. 
A product is thus formed called “ red starch ” (c/. A. Meyer 
sec . Rosenberg 24), which is supposed to be an excretion 
which, at a more advanced stage, is stored in the epidermal 
cells or also further used for mucilage. Also the common 
starch, “ blue starch,” occurs in some species and is trans¬ 
formed into mucilage. 
