DEVELOPMENT OF A CHERRY 



DI-:\'I-:L0PMEXT of a fmll from 

 a flower is a process the details 

 of which vary widely in dif- 

 ferent species of plants, but of 

 which the general outlines are fairly 

 constant. In general, it may be said 

 that the internal changes are very 

 complicated but the external changes 

 quite simple. The process can be 

 easily followed in the accompanying 

 illustrations, made from Japanese flower- 

 cherries {Prunus pseudo-cerasus) and 

 Japanese apricots {Prunus mumme) and 

 considerably enlarged. 



Starting with the flower, as shown in 

 Figure 8, we notice first of all the beauti- 

 ful ]jink petals. These represent the 

 expenditure of an immense amount of 

 energy on the part of the tree, and yet 

 have no direct connection with the 

 production of seeds — which may be 

 said to be the tree's main purpose in 

 life. When the ground below the tree 

 is wholly carpeted with fallen petals, it 

 may look as if the amount of energy 

 thus used was wasted, but as a matter 

 of fact the petals have served their 

 purpose, and nearly every one knows 

 that their purpose is a very useful one — 

 that of attracting insects to the flowers, 

 and thus securing cross-pollination of 

 the blossoms, in order that two lines 

 of ancestry may be united in the seed, 

 and the resulting plant thus benefit 

 from the traits of two ]3arents. After 

 the petals have fulfilled their end in 

 attracting bees to the flower, they are 

 of no further use to the tree, and arc 

 dropped. 



The other conspicuous parts of the 

 flower are the stamens or pollen- 

 bearing organs, and the style, an organ 

 designed to catch jjollen carried either 

 by wind or insects and transmit it to 

 the ovule lying in the ovary below. 

 It is not necessary here to follow out 

 the details of this process of jjollination 

 — most readers understand how the 

 pollen grain sends a long tube into the 

 style and down to the ovary, and how 

 the cell-nuclei of the pollen grain slip 

 down this tube and unite with the 

 278 



ox'ulc. There are then two i^airs of 

 cell-nuclei; one pair unites to form the 

 embryo, and the other to form what is 

 known as the endosperm — the starchy 

 material surrounding the actual germ. 



This union of the male and female 

 cells — what the gcnetists call zygosis — 

 not only starts a com])licated series of 

 cell divisions in the ovule, leading to 

 the production of the seed, but also 

 stimulates the remaining parts of the 

 flower to renewed growth. The sta- 

 mens, whose function is finished after 

 they have shed their pollen, wither and 

 drop ofif in time. The style has also 

 finished its work after it has furnished 

 a route for pollen grains to reach the 

 ovule, and it accordingly begins to 

 wither; but as it is firmly attached, 

 being in reality a modified prolongation 

 of the end of the stem, it remains in 

 place for a long while, frequently until 

 the fruit has reached considerable size, 

 as shown in the left of Figure 9. 

 Finally, however, with the increasing 

 size of the fruit, a layer of abscission 

 cells is formed at the base of the style, 

 all its nutrition is cut off, and the wind 

 some day blows it away. 



We have thus disposed of all the 

 parts of the flower — petals, stamens and 

 style — which were most conspicuous 

 when it first apjjeared. Meantime, a 

 ])art that was then apparently of little 

 importance has developed remarkably. 

 This is the ovary, which is from a 

 historical point of view a thickening of 

 the stem to act as a receptacle for the 

 ovule — which, when fecundated, be- 

 comes the seed. As the seed develops, 

 so does the ovary enclcsing it. The 

 changes here are princijjally chemical 

 in nature, and not yet wholly under- 

 stood. The tissues of the ovary swell 

 ujj and become distended and succulent. 

 Part of the starch is changed into 

 sugar; considerable quantities of acid 

 are formed, coloring matter is dejjosited 

 all through the tissues, and finally, 

 aromatic substances are created. This 

 by no means catalogues all of the com- 

 l)iex chemical changes, but it suggests 



