AS PE0TECT1VE AGAINST BADIATION. 



681 



the petiole has not elongated sufficiently to allow of the pairs of 

 leaflets being separated. As the petiole grows the whole collection 

 of leaflets becomes more pendulous until they expand, and the 



Fig. 8. 



Fig. 7. 



Fig. {). 



Fig. 7. Rose. Younger leaf erect ; older with petiole curved and half-developed 



leaflets. 

 Fig. 8. Pea. Leaf emerging from between the stipules ; the leaflets conduplicate. 

 Fig. 9. One stipule removed to show the erect bud within and protected by the 



stipules. 



leaf ultimately assumes the horizontal positk n. In the Garden 

 Bean the leaves are conduplicate ; but the margins are involute as 

 well, so that the leaflets resemble so many quills. 



(ii) pendulous. Of the two types the following may be selected : — 

 The French Bean, Wood-Sorrel (Oxalis), Clover, and Laburnum 

 as being ternate, and the Horse Chestnut and Virginian Creeper 

 as being digitate ; while the Walnut will exemplify the pinnate 

 type. 



The French Bean (Phaseolus vulgaris) bears at first a pair of 

 unifoliate leaves ; but those which succeed them are ternate. 

 While very minute in size (one half to three quarters of an inch 

 in length) the leaf is horizontal, but the leaflets are conduplicate 

 with their edges uppermost. When a little larger (say, one and 

 a quarter inches) the petiole bends down angularly, and the 

 leaflets are in vertical planes, holding identically the same 

 positions as when adult and asleep. As they increase in size, the 

 leaflets rise up and take a horizontal position. They now become 

 subject to hypnotism, falling at night and rising again by day. 



The Wood-Sorrel (fig. 12), Clover (fig. 11), and Laburnum 

 (fig. 19) all agree in having their three leaflets conduplicate, 



