192 GENERAL BOTANY 



pedicels spring, and the umbels are themselves col- 

 lected into larger umbels. This type of inflorescence 

 is so distinctive that the name UMBELLIFER^E (umbel- 

 bearing) has been given to the family to which these 

 last belong. Some of the other umbels are really 

 cymose in origin, see below. 



(v) The capitulum or head, when the flowers are 

 sessile on a flat or slightly convex receptacle, as in 

 the Sunflower, Zinnia, and all plants of that kind. 

 This may be considered as formed from an umbel 

 by reduction of the pedicels, so that the flowers 

 become sessile at the end of the common peduncle ; 

 or as a condensed spike, the axis of which is shortened 

 almost to nothingness, and expanded laterally. 



In the raceme the lower flowers open first, the 

 upper and younger later, and so of course, it is in 

 the spike. In correspondence with this, in the true 

 head the outermost flowers open first, the innermost 

 last, as can be seen in any Sunflower. This type of 

 inflorescence is again so distinctive as to have given 

 the name COMPOSITE to a very large and important 

 family of plants (almost the largest of all families), 

 which include EUPATORIUM the Hemp-agrimony, 

 HELIANTHUS the Sunflower, COSMEA, GAILLARDIA, 

 CHRYSANTHEMUM, GNAPHALIUM the Everlasting, 

 CNICUS the Thistle, TARAXUM the Dandelion, SONCHUS 

 the Sow-thistle, COREOPSIS and all plants like them. 



Condensed inflorescences very similar in appearance 

 to the capitulums of the COMPOSITE, occur in other 

 families. The head of ERIOCAULON the Hat-pin plant 

 of the hills, is composed like that of the COMPOSITE, of 

 small flowers massed together with a common involucre 



