V. FRUITS 



A Typical Fruit, — the Pea or Bean Pod. — In the study of the 

 flower of the sweet pea it was seen that the pistil of the flower 

 continues to grow after the rest of the flower withers. If we 

 remove the pistil from such a flower and examine it carefully, 

 we find that it is the ovary that has enlarged. The locule of the 

 ovary has become almost filled with a number of almost spherical 

 bodies, attached along one edge of the ovary. These we recognize 

 as the young seeds. 



Study of Bean or Pea Fruit. — The pod of the pea or string bean will show 

 us these facts more clearly. Examine, and then draw, natural size, an un- 

 opened pod. Label 

 the ovary, peduncle, 

 remains of style, stig- 

 ma and calyx if you 

 can find them. Then 

 split open the pod 

 and make another 

 drawing that will 

 show the seeds. La- 

 bel the stalk that at- 

 taches each seed to 

 the wall of the pod. 

 This is called the fu- 

 niculus. That part 

 of the oxaxy wall 

 which bears the seeds 

 is the placenta. The 

 entire ovary wall is 

 called the 'pericarp. 

 The walls of the pod are called valves. Show the above parts by label- 

 ing your drawing. 



The pod, which is in reality a ripened ovary with other parts of the pis- 

 til attached to it, is considered as a fruit. By definition, a fruit is a ripened 

 ovary together with any parts of the flower that may he attached to it. The chief 

 use of the fruit to the flower is to hold, to protect, and ultimately to dis- 

 tribute the seeds where they can reproduce young plants. 



Formation of Seeds. — Each seed has been formed as a direct result of 

 the fertilization of the egg cell (contained in the embryo sac of the ovule) 

 by a sperm cell of the pollen tube. 



Forms of Fruits; the Achene,the Simplest Fruit. — The forms taken 

 by fruits are very numerous. Naturally the simplest of all fruits would be 



50 



Fruit of the black locust ; a legume, showing the attachment 



of the seeds. 



