CALYCIFLOR.E 265 



The leaves are coated with wax — an adaptation to 

 enable the plant to resist dry conditions. In the 

 maritime form they are glaucous. The spinous 

 leaves and involucral bracts are an efficient protec- 

 tion to the plant, serving it in the same stead as the 

 spines in the thistle to prevent browsing animals from 

 feeding on it. They are also an adaptation against 

 drought. 



Daneweed, Hundred Thistle, Hundred-headed 

 Thistle, Watling Street Thistle, are other names for 

 this plant. 



Eryngium campestre. — In Fig. 56 the clasping 

 opposite stem-leaves armed with prickles are well shown, 

 as also the spinose involucre and Jhe cyme-like head of 

 flowers. 



Knotted Hedge Parsley {Caucalis nodosa). 



In this prostrate trailing plant we have a good 

 example of an adaptation to the habitat. The Upright 

 Hedge Parsley grows at the base of bushes by the 

 wayside, not often on banks. This plant is common 

 on slopes, and is thus specially fitted to creep over 

 the surface. If erect it would not so well cope with 

 the force of the wind, which is stronger in such 

 situations than in the habitat of the upright form. 

 It conforms itself, moreover, to the surface, creeping 

 in and out over the rugosities or uneven or convex 

 sides of such slopes. 



The Knotted Hedge Parsley is found throughout 

 the British Isles and in the Channel Islands. It seems 



