MORPHOLOGY OF REPEODUCTIVE ORGANS 127 



main axis is racemose in its general arrangement, but it bears a ter- 

 minal flower; the secondary and later axes are reversed racemes. 

 0. The Thyrsus. — This is somewhat more regular than the 

 mixed panicle, which it resembles in having the main axis 

 racemose. The secondary and later ones are cymose, and the 

 successive branches are so disposed that the cluster is narrower 

 at the apex and base than it is in the centre, having thus almost 



Fig, 241. 



Fio. 242 



Fig. 241. Mixed panicle of the Privet {^Ligustrum vulgare). a'. Primary 

 axis, a'', a". Secondary axes, a'", a"'. Tertiary axes, c, c. The central 

 flowers of the respective clusters, which are seen to be in a more expanded 

 state than those surrounding or below them. Fig. 242. Thyrsus of Vine. 



the shape of a double cone. Examples are seen in the inflo- 

 rescence of the Lilac and the Horse Chestnut. An almost com- 

 pound thyrsus is seen in the Vine (fig. 242). 



Light is often thrown upon the construction of the forms of 

 the inflorescence by the study of the phyllotaxis of the plant. 

 The racemose types are found associated with both verticillate 

 and alternate leaves, but the generally marked aeropetal develop- 

 ment makes their interpretation easy. More difficulty is found 



