THE REPRODUCTIVE SYSTEM 343 



to it. Traces of this flattening may be observed commonly 

 even in the petiole on the upper or inner surface, especiahy 

 near the base. These tests applied to the foliage of colum- 

 bines, for example, will show why it must be considered as 

 made up of branched leaves — decompound leaves with many 

 leaflets — rather than a branched stem bearing many simple 

 leaves. 



The stem and leaves of the marsh-marigold, as of marsh- 

 loving plants in general, are quite smooth and unprovided 

 Avith any hairy or other protective covering. Plants or parts 

 in this condition are described as glabrous.^ When covered 

 with soft, downy hair they are said to be pubescent." Many 

 ranunculaceous plants, especially those growing in dry, sunny 

 places (as for example the pasque-flower, the tall crowfoot, 

 and the bulbous crowfoot) are pubescent, particularly when 

 young. 



103. The reproductive system. Turning now to the 

 flowers of the marsh-marigold it will be noticed that they 

 grow either at the tip of the main axis or on stalks which 

 arise from the axils of upper leaves. On the side of the 

 flower-stalks, or subtending them, may be sessile leaves or 

 more or less scale-like leaf -members. Such leaves subtending 

 a flower or a flower-cluster are called bracls,^ or when borne 

 upon a floAver-stalk they are termed bradlets. The stalk of 

 a flower or flower-cluster is distinguished as its peduncle.^ 

 We speak of a blossom or flower-cluster as an inflorescence.'" 

 Thus we say that tlu^ inflorescence of the marsh-marigold 

 consists of a terminal flower, and a few axillary ones, with 

 bracts and sometimes bractlets. It should be noted that 

 the terminal flower opens before the lateral ones, thus putting 

 an end to further elongation of the main axis. Such an in- 

 florescence is therefore called determinate. It is also de- 

 scribed as cymose because the form of cluster which typically 

 results from the determinate mode of growth is called a 



' C.la'-brous < L. glahcr, without hair. 



- Pu-bes'-cent < L. puher, downy. 



' Bract < L. hractea, a thin plate. 



* IV-(lun'-cle < L. pedimculus, (Uminutive of pes, pedis, foot. 



^ In-ilor-es'-cence < L. in, in; florescere, begin to blo.ssom. 



