LABORATORY STUDIES OF THE FRUIT 145 



Cranherrij. Cross section, showing cavities and attachment of seeds 

 (x 2). The terminal depression showing remains of the flowers 

 ( X 10). Soft, fleshy fruits of this sort are termed herr^les. 



Checkerberry. — Dissect the fruit. What is the morphological 

 nature of the lower, fleshy part? 



Draw a longitudinal section to show all parts — including the seeds 

 in one of the cavities — and their arrangement (x 3). 



The Rose hip. — Examine the fruit to discover, if possible, where 

 the floral parts were situated. Cut the hip open. Are seeds seen? 

 Are seeds of Angiosperms produced in an open receptacle or cavity, as 

 these seedlike bodies are? Are they seeds or fruits? The hollow, 

 pulpy portion bearing them on its inner surface is an enlarged 

 receptacle. 



Draw a diagram representing a longitudinal section ( x 2-3). 



Exercise XXXYI. The Seed 



The student is already familiar with the interior of the seed — with 

 embryo and albumen. The integuments need to be looked at more 

 particularly thafi has been done heretofore. 



Squash. — Xotice the place at which the seed was broken from its 

 connection with the placenta. It is called the liilum. Beside this there 

 is a distinct aperture leading into the interior, the rnicropyle. Cut 

 away the shell. How many seed coats? This is the characteristic 

 number. The outer is the testa; the inner, the tegmen. 



Draw a cross section of the Squash seed (diagrammatic). 



Castor Bean. — On one side observe a straight, dark line, running 

 three quarters the length of the seed (the raphe). At one end is a 

 very slight elevation, the point at which the coats are organically 

 connected with the kernel ; this point is the chalaza. At the other 

 end is the hilum, nearly covered by a structure called the caruncle. 



Bean. — At one side of the hilum is the micropyle, more easily made 

 out if the material has been properly soaked. On the other side of 

 the hilum, running to the end of the bean, is a ridge, more or less 

 indistinct — the raphe. Overlying its inner extremity, next the hilum, 

 is a heart-shaped, purple excrescence, called the strophiole. 



Draw the bean, showing the features indicated ( x 3). 



Outgrowths of the testa. — By the aid of the hand lens make 

 enlarged drawings of the seeds of ^lilkweed and of the Trumpet 

 Creeper. Cut the seed of the Cotton Plant in half. Draw the 

 section, so as to show the length of the Cotton fibers relatively to the 

 diameter of the seed proper. What is the' use of these outgrowths ? 



Exercise XXXVII. The Fruit in Relation to Dissemination 



The need of dissemination will be most keenly realized by a rough 

 computation of the number of seeds produced by a single plant, all 



OCT. OF BOT. — 10 



