yS THE FLOWERING PLANT. 



the result, common examples of which are wild plantain and 

 wheat. Varieties of spike are the spadix (fig. 33), with fleshy 

 axis (e.g., arum), and the amentum or catkin, with scaly bracts, 

 as seen in willow and hazel. 



(2.) We now come to cases of simple racemose inflorescences, 

 where, by suppression of internodes, the main axis remains 

 extremely short. Imagine a telescoped raceme. The pedicels 

 would all start very close together from the abbreviated axis, 

 looking, so to speak, like the ribs of an umbrella turned inside 

 out. Such an inflorescence is an umbel, as seen in ivy. Its 

 nature may be known by the centripetal way in which the flowers 

 open. In a case like this, the bracts, from the axils of which the 

 pedicels arise, if they do not disappear altogether, are crowded 

 into an involucre or circlet. The capitidum or head is what we 

 should get if a spike were telescoped, or if the flowers of an 

 umbel became sessile or nearly so. The axis is here more or 

 less dilated, and may be rounded, conical, or globular in shape. 

 Common red and white clover are good examples, and the bracts 

 are here readily seen. A further interesting point about clovers 

 is the fact that among the numerous species we find all gradations, 

 from short spikes (crimson clover, a cultivated form) down to 

 well-marked heads. The stumpy axis is often called receptacle, 

 but must not be confounded with the floral receptacle. The 

 extremely large and important family of Composites, including 

 daisy, dandelion, sunflower, thistle, <fec, &c, is characterized by 

 the possession of heads. Take, for instance, a daisy. A beginner 

 would very likely mistake the white part for a corolla, and a lot 

 of little green leaves outside this for a calyx, 

 but would then be puzzled by the yellow 

 centre. We have, in fact, not a single 

 flower, but a very large number, crowded 

 into a head, and often termed, from their 

 small size, florets. They can easily be picked 

 off the receptacle, and it is not difficult to 

 make out the nature of the central ones which 

 compose the yellow "disk." The white " ray " 

 is made up of somewhat modified florets. The 

 apparent calyx is an involucre made up of the 

 Fig. 34.— Section of Fig. outer bracts. It can easily be seen that tjie 

 mon U receptacieT/" florets open centripetally. In thistle, dande- 

 flowers lining the \[ on an( j groundsel the florets are all alike. 



cavity. ° 



The fig is a modified head bearing florets on 

 the inner side of a thickened hollow common receptacle (fig. 34). 

 Compound racemose inflorescences have their branches, of secon- 

 dary or higher order, constructed on one or more of the types 



