Ill] MIXED INFLORESCENCES 29 



them to illustrate the kinds of difficulties to be expected 

 when the morphological sign-posts, as it were, are lacking. 



Any of the above racemose inflorescences may occur 

 branched, instead of simple, i.e. the primary axis bears not 

 single pedicellate flowers, but secondary axes which branch 

 in their turn (Fig. 9). We thus get forms such as the 

 compound raceme raceme of racemes or true Panicle, 

 e.g. Yucca, Anthericum ramosum, Desmodium racemosum, 

 Virgilea lutea. In most Grasses we have compound spikes 

 (spikes of spikelets), e.g. Wheat, Rye, Lolium, &c., or loose 

 racemes of spikelets commonly termed panicles as in 

 Bromus, Digraphis, Milium, Holcus, &c. Compound 

 umbels i.e. umbels of umbels are more often met 

 with in the Umbelliferse than are simple ones ; in these 

 cases the partial umbels are termed Umbellules and their 

 involucres, when present, Involucels e.g. jEgopodium, 

 Carrot, Cow Parsnip, &c. 



With regard to these compound inflorescences we may 

 distinguish between homogeneously compound e.g. a 

 raceme of racemes and heterogeneously compound forms 

 e.g. a raceme of spikes. 



We shall meet with many cases of mixed compound 

 spicate inflorescences among forest trees, usually as spikes 

 or catkins of small cymose groups. These will be dealt 

 with in detail in the sequel. 



