220 APPLIED BIOLOGY 



berry. Each grain is simply a dry fruit, and contains the true 

 seed. 



214. Simple Fleshy Fruits. In all the cases described 

 above the wall of the ovary forms a hard or dry case or shell 

 around the seed or seeds. In the following fruits the ovary- 

 wall becomes fleshy, with a relatively thin external skin or 

 rind. 



A date is the simplest fleshy fruit, because it contains but 

 one seed, which was formed from a single ovule, while the 

 wall of the ovary developed the edible fleshy part and the 

 thin rind. If one cracks a date seed, it is found solid like a 

 grain of wheat, except that the food in wheat is starch while 

 in the date seed it is a hard woody substance (cellulose). 



Tomato. (L) Materials : Small green tomatoes with short stems 

 attached, collected in the fall and preserved in formalin, will be found 

 most satisfactory for study in the winter or spring. Some flowers in 

 formalin will also be useful. Note the calyx; how many sepals? 

 Remove a piece of skin ; observe that it is very thin and tough. 

 Make a cut across the middle of a tomato (transverse section). 

 Examine the cut surface; note that the entire interior is soft and 

 pulpy. How many seed-cavities do you find ? They are filled with 

 a soft placenta to which the numerous seeds are attached. Note the 

 gelatinous covering of the seeds. Observe the thickness of the ovary- 

 wall, and also of the partitions. 



Other fruits like the tomato, in which the entire wall of the ovary 

 becomes fleshy, are the grape, cranberry, egg-plant, banana, garden 

 pepper, orange, lemon, persimmon, gooseberry, currant. 



Lemon. (L) The lemon is like a tomato in structure, but has a 

 very tough leathery rind. On the stem end of the fruit you may 

 find the dried-up remains of the calyx ; how many sepals ? At the 

 opposite end is a knob-like projection to which was attached the 

 stigma of the pistil. 



Remove the remains of the calyx and observe the ring of little 

 dots left in the depression thus made. These are the ends of the 

 fibro-vascular bundles which passed from the stem (peduncle) of 

 the flower up into the pistil. What was their function? 



The surface of the lemon is roughened by numerous pits which, 

 if examined (by making thin sections of the yellow part of the rind, 

 and placing under a lens) will be found to be little pits filled with oil, 



