42 



ORGANOGRAPKY. 



spike is similar to a crowded raceme, with the flowers ses- 

 sile (Fig. 91). Two special forms of the spike have peculiar 

 names, namely, the spadix (Fig. 86), 

 ■which is fleshy (and commonly sur; 



rounded by a spathe) ; and 



the catkin, or ament, 



which is scaly (Fig. 92). 



The head difiers from a 



spike in that the axis is re- 

 duced, crowding the flowers 



into a head-like cluster (Fig. 

 ^2 93). A panicle is an open 

 and more or less compounded raceme 

 or corymb (Fig. 94). 



50. The cyme is a determinate or 

 definite flower-cluster, with a flat or convex top. It resem- 

 bles the corymb somewhat, except that in the latter the flow- 

 ering is centripetal, while in the cyme it is centrifugal (Fig. 

 95). A crowded cyme is called a fascicle. Many of the 

 clusters are often compound, as compound umbels, compound 



t cymes, etc. The two 



_ classes of inflores- 



' '^ cence may be repre- 



sented in one and 

 the same plant; thus 

 the Mint Family 

 has cymes or fasci- 

 cles, which are cen- 

 trifugal in their flow- 

 ering, but these are 



Fig. 92. Catkin of the American Hazel. Fig. 93. Head of Clover-flowers. Fig. 

 94. Diagram of a Panicle. Fig. 95. Diagram of a Cyme. 



