THE STONECROPS 



its favourite habitat is the tops of walls and similar 

 places, and from the additional fact that its small 

 thickened leaves and stems are biting to the taste. 

 In Figs. 94 and 95 (Plate 6S) the plant is shown in 

 detail, and also growing in the mass on the roof of 

 a barn ; but to appreciate it properly in the latter 

 case, its expanse of bright green, surfaced with its 

 golden star-like flowers, should be seen in the 

 bright sunlight. 



There are some nine or ten species of these 

 stonecrops found in Britain, and the wall-pepper 

 represents the smallest of them, while the orpine 

 is the largest ; between the two plants we get 

 species showing almost every gradation from the 

 little thickened and closely-imbricated leaves of 

 the wall-pepper, to the large, fleshy ones (often 

 more than two inches across) of the orpine. All 

 the nine or ten species, however, are succulent ; 

 and it is this latter feature to which I particu- 

 larly wish to call attention now. 



These plants have, like the cacti considered in 

 an earlier chapter, adapted their structures to dry 

 rocks and stony situations. They absorb moisture 

 and store it in their tissues against a time of 

 drought. I have endeavoured to illustrate this 

 characteristic in a practical way in Figs. 96 to 99 

 (Plates 69 and 70). The first figure shows a 

 branch of the orpine placed beside another of a 

 thin-leaved plant, the Mock Orange {Philadelphus 

 vulgaris). As will be seen, both branches are 

 arranged on the end of a perforated box, and 

 exposed to ordinary daylight, and without a 

 L 161 



