G6 



HOW PLANTS ARE PROrAGATED. 



corolla-leaves, ami the inner corolla-leaves change gradually into stamens, — show- 

 ins that even stamens answer to leaves. 



198". How a stamen answers to a leaf, according to the botanist's idea, Fifr. 

 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, Avhich 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 

 (Fig. 154, 15G) is regarded by the botanist as if it were 

 made by the folding up inwards of the blade of a leaf, 

 (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 tliis, destitute of skin, becomes the stig- 

 ma. To understand this better, compare Fig. IGO, represent- 

 ing a leaf rolled up in this way, with Fig. 156, and with Fig. 

 IGl, 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 

 or seeds are attached to, is called the Placenta. 



200. Varieties or Sorts of Flowers. Now that we have learned 

 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 



153 



Flan of a Stamen. 



Plan of Pistil. 



