220 Introduction to Botany. 



stamen on a large scale, showing the manner of the de- 

 hiscence of the anthers. Draw a stigma on a large scale, 

 showing the character of its surface. 



Of what use is the spathe ? Note the behavior of in- 

 sects while visiting the flowers. Can you see any use for 

 the sterile upper part of the spadix ? Can it, among other 

 uses, serve the attractive function of a corolla? 



The student will find it interesting to observe the be- 

 havior of this plant throughout the season. Examine 

 plants in their natural habitat, and find answers to the fol- 

 lowing questions : What becomes of the spathe and sterile 

 portion of the spadix ? What kind of fruit does the ripened 

 pistil become ? When and in what way do the seeds be- 

 come planted in nature ? At what time of the year do the 

 leaves wither away ? After the above-ground parts have 

 withered and the corm has entered into its winter rest, can 

 the inflorescence and leaves of the following season already 

 be found in an embryonic condition in the apical bud of 

 the corm ? 



Cut the corm in two and put a drop of iodine on the sur- 

 face. Does a purple color ensue, indicating starch as re- 

 serve food ? The corm contains a very acrid substance. 

 In tasting it only a very small piece should be placed for a 

 moment on the tongue, for if much is put into the mouth 

 and chewed the result is exceedingly painful. This acrid 

 substance is doubtless a protection against the depredation 

 of animals, for when it, being volatile, has been driven out 

 by boiling or drying, the corms are found to be edible. 

 Exceedingly minute and sharp crystals of calcium oxalate 

 occur abundantly in the corms, but they do not cause the 

 pain when the fresh corms are eaten, as some have 

 thought. 



If obtainable, study Arisczma dracontium and note the 



