80 



INTRODUCTION TO BOTANY 



kinds which usually grow in very damp soil or in swamps, 

 such as the jack-in-the-pulpit, skunk cabbage, white hellebore, 

 papaw, and some magnolias, are frequently large-leaved plants. 

 Many plants which grow in extremely dry soils, or in regions 

 where the summer rainfall is scanty or altogether lacking, are 

 characterized by small leaves, often awl-shaped or thread-like. 

 Few familiar examples of such plants with highly reduced leaf 

 surface are to be found among the wild 

 plants of the northern United States. 



FIG. 64. The crowberry 



This plant has minute leaves 

 with their margins rolled 

 under. It thrives in dry, 

 exposed situations. About 

 one half natural size 



FIG. 65. A fleshy-leaved plant (Mesem- 



bryanthemum) with much water stored in 



the stiff, clustered leaves 



After De Candolle 



The crowberry (fig. 64) is one good instance of the kind, 

 and a few weeds of the Pink family, some St.-John's-worts, and 

 some little spurges are other examples. The heather (Erica), 

 often cultivated in greenhouses, is an excellent instance of 

 minute, awl-shaped leaves. 



Thick, fleshy leaves (fig. 65) are common in plants of desert 

 or semi-desert regions. Some of these leaves are almost cylin- 

 drical ; others are tongue-shaped ; others, like those of the cen- 

 tury plant, are thick and broad at the base and taper to a spiny 

 tip. All fleshy, or succulent, leaves hold much stored water for 

 use in seasons of drought. 



