MODIFIED LEAVES 



73 



insects. Scales are always present upon the underground stems 

 of perennial plants, and vary much in size. Upon the rhizomes 

 of couch-grass and potato, they are small and membranous, 

 while the leaves of a resting bulb are large scales, some of which 

 are thick and fleshy, and stored with food. 



(c) Bracts and Bradeoles. — The leaves which occur upon the 

 stem at points where 

 the flowers and inflores- 

 cences arise are termed 

 bracts and bradeoles (see 

 p. 89). They are very 

 variable in size, texture 

 and colour. In some 

 plants they cannot be 

 distinguished from the 

 ordinary green foliage- 

 leaves except by their 

 position ; more often 

 they are rudimentary 

 leaves somewhat re- 

 sembling scales. The ' 

 chaffy bracts surround- 

 ing the flowers of grasses 

 are termed glumes. In 

 Arum, Iris, Narcissus, 

 and snowdrop, a large 

 bract, termed a spafhe, 

 encloses the whole in- 

 florescence. 



The cup of the acorn and the husk of the filbert and hazel- 

 nut are persistent united bracts. 



Bracts are sometimes brightly coloured. 



{d) Floral leaves. — The special leaves constituting the chief 

 parts of a flower are texm&di Jloral leaves (see next chapter). 



Fig. 33. — A single compound leaf of pea ; st 

 Stipule; ^leaflet; ^tendril. 



