PART I.—STRUCTURAL. 9 
You must now try to find an example in which the fruit is 
nearly ripe. In this you will see that the sepals, petals, and 
stamens have fallen off, leaving minute scar-like markings on 
the thalamus, and that this portion has somewhat elongated. 
Only the carpels remain, but these have increased consider- 
ably in size, are now dry, smooth, and polished, somewhat. 
compressed, and with a flange or margin, and the style has 
become sharper and more hooked. This sort of fruit does not 
open to scatter its seed, but in course of time the wall or 
pericarp * decays, and the seed is thus liberated. Such a 
fruit is called an achene,{ and we define an achene as a 
1-celled (v.e., having one cavity), dry, indehiscent (not opening) 
fruit, formed of a single carpel and containing a single ovule. 
Remove one of these little achenes and open it. You will 
find that the ovule has ripened into a seed, and that this seed 
is attached at one side of the base of the fruit. Now make a 
longitudinal section so as to cut the seed 
lengthways. ‘The greater portion of it is goo 
occupied with a white substance (like the 
white of a coco-nut), which is the albumen 
or endosperm.{ Near the base of this 
occurs a very minute firmer body called the 
embryo, which is the rudiment or germ of 
the future plant. Enclosing the albumen is 
a thin brown shell, or testa. Under favour- 
able conditions of warmth and moisture the Fig. 6. Longitu- 
seed germinates, and the embryo gradually ie Sere 
° L cw 
develops a root and a leaf-bearing stem. of Buttercup 
To do this it uses up the store of albumen = (mag.). 
which has been laid up for it—a process 
analogous to that by which the little germ in the hen’s egg 
uses up the nutriment stored up for it, and so develops into a 
chicken. A seed like this of Buttercup, having a small slightly- 
developed embryo and a relatively large separate store of 
albumen, is said to be albuminous. 
Looking over the structure of our flower again, we see 
that the sepals are leaves specially modified to protect the 
parts within them, the petals serve chiefly as organs of attrac- 
tion to insects, the stamens contain the pollen, or male element, 
and the pistil contains the ovules, or female element. Hence 
the two latter are the important or essential organs, and are 
called the organs of reproduction. The two outer whorls are 
therefore sometimes called non-essential organs, though the 
term is not quite correct, as, even if they do not actually take 
* Gr. pert, round about; karpos, a fruit. 
+t Gr. achanés, not opening. 
t Gr. endon, within ; sperma, a seed. 
