Study of a Calla. 105 



cover the walls of the cavity. Are those above (near the 

 hole) like the basal flowers ? [Often they are all alike and 

 pistillate.] How many stigmas are there ? Are the flowers 

 sessile or on pedicels ? Are there bracts among them ? 

 Find the bracts around the hole, inside and outside. If 

 you have a very small fig split it and compare with c in 

 Fig. 81. What becomes of all these bracts? If you have 

 a ripe fig note that the flowers, becoming swollen with 

 juice, fill the cavity. Stem, calyx, and even styles and 

 stigmas help to make the pulp. With the help of the figure 

 and your specimens try to understand why botantists think 

 the outside of a fig is a stem. Think of the receptacle of a 

 sunflower. Imagine the lower surface very much enlarged. 



Make drawings similar to those here given and also of a 

 single flower magnified.* 



A calla and one of its leaves will be useful in the next 

 exercise. 



EXERCISE 55. 



Study of a Calla. You have been told in Exercise 48 

 that a calla is not a flower, but a spike of flowers enclosed 

 by a bract which does the work of a corolla. Jack-in-the- 

 pulpit, called also Indian turnip, a common plant of the 

 Atlantic forests, and the skunk cabbage of our swamps are 



* Evidently figs which have no staminate flowers cannot produce seeds 

 without the aid of some animal. A very small insect does this work for the 

 wild figs of the Mediterranean regions. Since the fruit grows much larger when 

 the flowers are fertilized, fruit-growers are endeavoring to naturalize the insect; 

 but without success, thus far. Even in figs containing both staminate and 

 pistillate blossoms, the latter seldom, if ever, produce seeds containing embryos. 



