96 



Elementary Botany 



VARIETIES OF SPIKE. 



A catkin or amentum is a deciduous spike of unisexual 

 flowers, as in the Oak (fig. 152), Hazel, or Willow. 



A spadix is a fleshy spike bearing several unisexual flowers, 

 the whole enveloped in a spathe, as in 

 the Arum (fig. 153). 



A strobilus is a spike of unisexual 

 flowers with membranous bracts, as in 

 the Hop. 



Fig. 152.— Catkin oramentum 

 of the Oak. 



Frn. 153. — Spadix of 

 Arum : a, barren sta- 

 mens ; i5, stamens ; c, 

 pistils. 



Fig, 154.— Cone of the 

 Scotch Fir. 



A cone is a spike of unisexual flowers with lignified bracts, 

 as in the Fir (fig. 154). 



VARIETIES OF RACEME. 



A corymb is a raceme where the stalks or pedicels are of 

 different lengths, the lower ones being the longest, so th:it the 

 flowers form a flat-topped head, as in the Hawthorn and some 

 species of Cerasus. ' 



A panicle is a compound raceme, that is, one where each 

 branch is itself branched, as in some Yuccas. 



A thyrsus is a panicle with very short pedicels, as in the 

 Horse-chestnut and Lilac. 



