AS PROTECTIVE AGAINST RADIATION. 



029 



to protect the younger ones, which are concealed beneath them. 

 Thus the protecting care is handed on to each leaf as it arrives at 

 maturity, until the whole series are developed and the branch and 

 leaves become horizontal. 



The tile-like arrangement of the uppermost stipules and subse- 

 quently of the leaves themselves, thus protecting the edges of the 



Fig. 2. Fig. 3. Fig. 4. 



The Lime in different stages of development. 



vertically placed leaves beneath them, reminds one of a very 

 similar method of protection in Trifolium repens when asleep. 

 In this plant the two basal leaflets rotate so as to bring their 

 upper surfaces in contact and their blades vertical, while the ter- 

 minal leaflet revolves through 180° and comes down upon the 

 upper edges like an arched roof above them * (figs. 5 and 6). 

 Fig. 5. Fig. 6. 



Trifolium repens. 

 Fig. 5. Leaf during day time. Fig. 6. Asleep, during night-time. After Darwin. 



In the case of the Hazel the process is much the same, but with 

 Ampelopsis VeitcHi the blade spreads out at once, however young, 

 and is not conduplicate ; but as it hangs vertically from its very 

 birth to its fall, it does not require any further protection beyond 

 what the leaves above it happen to supply by overhanging it. The 

 branches of this species cling so tightly to the wall that very 

 possibly a good deal of heat is radiated from the wall itself on to 



* Darwin, Movem. of Plants, p. 349, fig. 141. 

 LINN. JOURN, — BOTANY, VOL. XXI. » A 



