66 HOW PLANTS ARE PROPAGATED. 
corolla-leaves, and the inner corolla-leaves change gradually into stamens, — show: 
ing that even stamens answer to leaves. 
198. How astamen answers to a leaf, according to the botanist’s idea, Fig. 
158 is intended to show. ‘The filament or stalk of the stamen answers to ‘the 
footstalk of a leaf; and the anther answers to the blade. The lower part of the 
figure represents a short filament, bearing an anther which 
has its upper half cut away; and the summit of a leaf is 
placed above it. Fig. 159 is the whole stamen of a Lily 
put beside it for comparison. If the whole anther corre- 
sponds with the blade of a leaf, then its two cells, or 
halves, answer to the halves of the blade, one on each side 
of the midrib; the continuation of the filament, which con- 
nects the two cells (called the connective), answers to the 
midrib; and the anther generally opens along what answer 
to the margins of a leaf. 
199. It is easy to see how a simple pistil answers to a 
leaf. A simple pistil, like one of those of the Stonecrop 
(Pig. 154, 156) is regarded by the botanist as if it were 
made by the folding up inwards of the blade of a leaf, eee 
(that is, of what would have been a leaf on any branch of the common kind,) so 
that the margins come together and join, making a hollow closed bag, which is the 
ovary; a tapering summit forms the style, and some part of the 
margins of the leaf in this, destitute of skin, becomes the stig- 
ma. To understand this better, compare Fig. 160, represent- 
ing a leaf rolled up in this way, with Fig. 156, and with Fig. 
161, which are pistils, cut in two, that the interior of the ovary 
may be seen. It is here plain that the ovules or seeds are at- 
tached to what answers to the united margins of the leaf. The 
particular part or line, or whatever it may be, that the ovules 
y or seeds are attached to, is called the Placenta. 
bcs ule 200. Varieties or Sorts of Flowers, Now that we have learned 
ey abe how greatly roots, stems, and leaves vary in their forms and 
appearances, we should expect flowers to exhibit great variety in different species. 
In fact, each class and each family of plants has its flowers upon a plan of its 
own. But if students understand the general plan of flowers, as seen in the 
