14 



INTRODUCTION 



A sedge ; the umbrella plant {Cyperus alternifolius) or 

 the Egyptian paper plant {C. papyrus), so common in 

 greenhouses, will either of them do very well, though our 

 native wild plants are always preferable when they can be 

 obtained. 



Healthy plants of oxalis and tropasolum. 



A twining vine ; hop, morning glory, kidney bean, etc. 



A glass jar with one or two water plants, such as pond- 

 weed (/"^/(^^zci^^/i^k), hornwort {Ceratopkyllum), bladderwort 

 ( Utricularia), or pickerel weed {Pontederia), etc. 



English Scale, 

 Four Inches 



Metric Scale, 

 Ten Centimeters 



z. — A comparative scale of the English and 

 metric systems of length measure. One decimeter 

 = ID centimeters = loo millimeters = approximately 

 4 inches. 



3. — A comparative 

 scale of the Centigrade 

 and Fahrenheit ther- 

 mometers. On the Cen- 

 tigrade scale o = the 

 temperature of melting 

 ice, and 100° = that of 

 boiling water. 



