THE INFLORESCENCE 



75 



flower of a lesser branch system (see Palmae). (The scales that make 

 up the lorica have been called emergences of the ovary wall, not 

 bracts, because believed to be borne directly on the wall, but sections 

 of the flowers show the ovary free from the encasing lorica.) 



Fig. 33. Sketches of longitudinal sections of young female flowers and inflorescence 

 with involucre prominent. A, Qucrcus rubra; B, Fagus americana. {After Langdon.) 



The multiflowered catkins of the Amentiferae are often described as 

 racemes and spikes, but probably none of them is of so simple a type. 

 The catkins of the Betulaceae are fine examples of reduction from a 

 complex cymose inflorescence. The "florets" represent, in various genera, 

 a cymule of three flowers, with their 

 subtending bracts in various stages of 

 connation and reduction (Fig. 35). 



In the elms, Ulmtis americana has 

 a compacted panicle; U. thomasi, a 

 raceme; U. piimila, a head — an obvious 

 reduction series. In Acer, A. pseud o- 

 Platomis has a panicle; A. spicatum and 

 A. pennsijlvaniciim, a simple raceme or 

 a raceme with a few weak basal 

 branches; A. saccharum, an umbellate 

 cluster; A. ruhruni and A. saccharinum, 

 few flowered heads with vestiges of the 

 rachis. 



The solitary flower of Viola is the 

 surviving median flower of a dichasium. 

 V. betonicifolia of Australia and Asia ^.^ ^^ loricate fruit of Metroxy- 

 has flowers in the axils of the pair of /on. (After L. H. Bailey.) 



