j6 THE FLOWERING TLANT. 



a tiower-stalk bearing one or a cluster of flowers grows right 

 up from the ground, it is termed a scape, and may either belong 

 to definite inflorescence, as in tulip, or indefinite, arising in 

 the latter case from a leaf-axil belonging to an underground 

 or abbreviated shoot, as in primrose and cowslip. 



It is usual for flowers to occur grouped together into clusters. 

 In other words, they are formed upon special branch-systems, 

 to which the term l inflorescences is usually given. The 

 branches of such a cluster arise from the axils, not of ordinary 

 leaves, but of bracts, which are mostly small, simple, and useless 

 for the purposes of foliage. Many plants, as orchids, show a com- 

 plete gradation between foliage leaves and bracts. On the other 

 hand, the transition may be very abrupt. In some exceptional 

 cases, e.g., shepherd's purse, the flower clusters possess no bracts, 

 so that the flower-bearing branches are not axillary. The con- 

 verse of this is not uncommon, i.e., the occurrence of bracts 

 without branches in their axils. They then, owing to their 

 small size, receive the name of brartlets or bracteoles, and are 

 situated not far from a flower, as, for instance, in pansy and 

 violet (fig. 51). Bracts may become large or otherwise con- 

 spicuous for special purposes. When brightly coloured, as in 

 hyacinth, they are termed petaloid, because tints other than 

 green are most usually found in the petals. A large sheath- 

 like bract, then known as a spathe, may surround an inflor- 

 escence. The large green structure enclosing the central column 

 of arum is of this nature (fig. 33). Another case is seen in the 

 onion. Smaller examples are found in the membranous structures 

 ensheathing the scapes of narcissus, daffodil, and snowdrop. 

 A spathe may be petaloid, as in the arum lily, where it is large 

 and of a brilliant white colour, which makes it look something 

 like a corolla. 



When the flowers are in the axils of ordinary leaves, their 

 stalks may be called peduncles, but in the case of a flower cluster 

 they are pedicels, the word peduncle being reserved for the main 

 axis. If the cluster branches more than once, the intermediate 

 stem structures are called partial peduncles. 



Racemose inflorescences are either simple or compound, i.e., the 

 lateral axes either terminate in flowers without branching, or 

 else branch to a greater or less extent. Otherwise expressed, 

 the lateral axes are pedicels in the former case, partial peduncles 

 in the latter. Simple racemose inflorescences are again sub- 

 divided according to the state of the internodes in the main 

 axis, which is long or short as these are well or ill developed. 



Inflorescence, therefore, may mean: — (1.) Arrangement of flowers; (2.) 

 a special flower-bearing branch system. 



