INFLORESCENCE-LEAVES OR FLORAL LEAVES 205 



as are the forms of the style-branches and the appendages borne by 

 these at the apex and by the anthers at apex and at base (see Androe- 

 cium and Gynaecium). 



Inflorescence-leaves or Floral Leaves. — Many special terms are applied 

 to the forms of infloi-escence-leaves, that is, the bracts subtending its 

 branches and the pedicels of the flowers, as well as those borne upon 

 the pedicel. Ordinarily they are conspicuously smaller than the other 

 leaves borne by the plant. 



With this reduced size, other modifications are noticeable, especially 

 the shortening or loss of the petiole and a general tendency toward 

 reduction to the scale-form, this tendency counteracted in variable 

 degree by a contrary tendency to preserve the characteristic leaf-form. 

 These leaves are commonly spoken of as the Reduced Leaves of the 

 Inflorescence. To this class belong the leaves of the involucre and the 

 scales often found upon the receptacle of the anthodium already con- 

 sidered. Individually, they are spoken of as bracts, the secondary ones 

 bractlets, and the ultimate very small ones bracteoles. Ordinarily the 

 changes here outlined as marking the development of the foliage-leaves 

 into the inflorescence-leaves are gradual, but in many cases there is an 

 abrupt transition from the one form to the other. 



A circle or cluster of bracts at the base of an inflorescence is termed 

 an Involucre, and this term is also applied to a single ^'cry large bract 

 occupying the same position, although this is more commonly known 

 as the Spathe. In most cases the modifications of leaves forming the 

 scales of involucres are entirely dii^'erent from those of bracts occurring 

 singly. They are usually much larger than such bracts, their form is 

 usually specialized in some way, and they are very frequently highly- 

 colored, serving the same purpose as neutral flowers. The bracts of 

 involucres are often amalgamated so as to form a cup or tube. 



Many one-leaved involucres are very peculiar, and their morphology 

 even more difficult to understand. The supposed leaf is sometimes a 

 phyllocladium. In some cases the flower appears to rise out of the 

 modified or unmodified leaf itself, as in the Tilia, the explanation in 

 these cases probably being that adnation exists between the inflores- 

 cence and the leaf. 



One group of Families, the grasses and grass-like plants, do not 

 possess any obvious perigone, its place being supplied by peculiarly 

 formed, adapted, and arranged bracts, in the form of scales or chaft', 

 and technically called Glumes, which give to this group of families the 

 title Glumaceae. In the rushes, these glumes really are a true 

 perigone, which is trimerous. In the sedges (Family Cijjxmceae, 



