THE AMERICAN BOTANIST, 



69 



shaped bodies, the pistils. These organs always have the 

 same relative position. The pistils are always in the cen- 

 tre of the flower, the sepals on the outside and the petals 

 and stamens between. The terms which I have just itali- 

 cised are necessary for even the beginner to know but they 

 are all in such common use that 'they are doubtless al- 

 ready familiar. 



In the stone-crop flower these diflerent organs are so 

 close together that most of its resemblance to a branch is 

 lost but, in the blossom of the spi- '-^ 



the production of seed, it is necessary that some of the 

 yello w dust or pollen contained in the stamens should fall 

 upon the pistil and stimulate their embryo seeds into 

 growth. Otherwise no seed would result. Thus the sta- 

 mens and pistils, being the only organs essential to the 

 work of the flower are called the essential organs. The 

 sepals and petals have no such important oflices to fill and 

 are absent from the flowers of many species. When pre- 

 sent, their functions are principally the protection of the 

 essential organs from cold, wet and mechanical injury and 

 the attraction and guidance of the insects that assist in 

 transferring the pollen from stamen to pistil. 



Leaving out of consideration for the present, flowers 

 of irregular shape, it will be found upon counting the parts 

 of the flower that there is not much variation from cer- 



Every complete flower has 

 these four kinds of organs but 

 not all flowers are complete. The 

 two kinds necessary to the plant 

 are the stamens and pistils. In 



der-flower (Cleome, fig. 3) the 

 parts are much more leaf-like in 

 arrangement. Here we see a cir- 

 cle of four small sepals, and 

 above it the four petals each on 

 a stalk while the single pistil in 

 the centre is raised above them 

 all. 



Fig. 3. 



