234 



BOTANY AND PHARMACOGNOSY. 



less. The inflorescence is a spike-like spadix having greenish- 

 yellow flowers. 



Many of the AraceiE possess an acrid juice. The acridity may 

 be due to certain acrid principles or to mechanical irritation caused 

 by the presence of raphides of calcium oxalate. Frequently these 

 principles are dissipated or destroyed on cooking and the plants 

 are then used as food, as the water arum (Calla palustris), 



Fig. 128. Water arum (Calla palustris) showing portion of rhizome, the broadly- 

 ovate and cordate leaves, and the inflorescence which consists of a cylindrical spadix and 

 an elliptical spreading spathe. 



which on account of its acrid principles is used as a remedy for 

 snake bites when in the fresh condition, but which on drying loses 

 its acridity and being rich in starch is used as a food (Fig. 128). 

 To this family also belong Jack-in-the-pulpit, or Indian turnip 

 {Ariscema triphyllum) , the acrid corm of which is used in medi- 

 cine; SKUNK CABBAGE {Spathycma fcetida), the fetid rhizome of 

 which has medicinal properties. A number of plants of the Arum 

 family are rich in starch, as the tubers of Xanthosoma edule of 

 Surinam which contain 62 per cent, of starch. . 



