THE CANADIAN HORTICULTURIST. 



united to make one compound pistil. 

 Nos. ij, 16 and 21 show how the ovules 

 arise within the base of the pistil. Many 

 of our edible fruits are formed, as we shall 

 see, by the extraordinary development 

 of the pistil, and it will be well to re- 

 member that the first indication of the 

 origin of such fruits is one or more lit- 

 tle tongues of tissue rising from the sur- 

 face of the stem at the tip of the branch. 



to become spherical, finally becoming 

 pulpy, a delicious fruit ot the simplest 

 origin — a modified pistil. 



Fig. 1522.— A to F North American Fox Grape. 

 (Vitis labrusca) A, branch with leaves and 

 tendrils ; B, unopened flower ; C, male flower, 

 D, female flower, with sterile stamens and 

 glands alternating with the stamens; E, F, 

 Cross and Longitudinal sections of the pistil ; 

 G to M, European Grape (Vitis vinifera). G, 

 flowering branch ; H, J, Longitudinal and 

 Cross sections of the berry ; K, L, M, the seed. 



One of the simplest of our market 

 fruits is the grape, illustrated in Fig. 

 1522. The figure A is a branch from 

 our American Fox grape, the ancestor of 

 many of our cultivated varieties. B 

 shows a flower of this species, the calyx 

 being a mere ring around the stem, 

 while the corolla never opens, but early 

 falls off, revealing the stamens as in C, 

 or the pistil with abortive stamens as in 

 D. Thus we see that the flowers of this 

 grape are of two kinds, male and female. 

 The only part of the flower that devel- 

 ops into the fruit is the flask-shaped 

 pistil, which after fertilization begins to 

 swell, becomes fleshy, loses its flask form 



Fig. 1523.— Sour Cherry. (Prunus cerasus)' 

 A, flower cluster; B, flower in longitudinal 

 sections, showing pistil sunken in cup-shaped 

 stem ; C, fruit in section. 



From the grape we pass to cherries, 

 peaches and plums, the cultivated 

 species all derived by America from the 

 old world. In Fig. 1523, the illustra- 

 tion B shows a cherry flower longitudinal 

 section. There are depicted flower stem, 

 calyx, corolla, stamens and a single pistil. 

 The same parts are present here as shown 

 in our diagram Fig. 15 19, but in the 

 cherry the parts are differently dispos- 

 ed.* The stem or axis instead of pre- 

 serving its conical form becomes cup- 

 shaped, bearing the pistil in the bottom 

 of the cup, and all other parts on the 

 rim of the cup. No one could tell by 

 looking at this flower alone what parts 

 would develop into fruit. It looks very 

 much as though not only the pistil but 

 also the cup-shaped stem would become 

 fleshy. But in the immediate develop- 

 ment after fertilization, the cup ceases 

 to grow, while the single pistil begins to 

 swell, the inner part of its wall becoming 

 stony, the outer part fleshy and edible. 

 The relation of stony and fleshy part is 

 shown in C(i523). Thus the fruit of 

 the cherry, the peach and the plum are 

 made solely from the enlarged base of 

 the pistil. These fruits are therefore 

 in origin the same as that of the grape. 



*In the following account the author has 

 chosen to regard the cup-shaped base of the 

 flower of Rosacea? as an extension of the stem 

 rather than as a calyx tube. 



54 



