MORPHOLOGY OF THE FLORAL ORGANS 121 



tribe Paniceae. In the series Poseoideae the pedicel is 

 usually not jointed below the spikelet but the rachilla 

 may be articulated below the first lemma, so that at 

 maturity the upper part of the spikelet falls away leaving 

 the glumes. There are exceptions in both groups. In 

 many species of Eragrostis the rachilla remains attached 

 to the pedicel and the lemmas fall away. 



The pedicel is sometimes differently developed in 

 the same inflorescence, as in many Andropogonese, where 

 the spikelets are in pairs, one being sessile and fertile, 

 the other pediceled and bearing a staminate spikelet or 

 only a bract which may represent a glume, or the spikelet 

 may be aborted, the pedicel persisting as a naked stalk. 



The pedicel may be grown fast to the axis as in Rytilix 

 and Manisuris. 



152. The glumes are the 2 empty bracts at the base of 

 the spikelet and are called respectively the first and 

 second glume. They usually differ in shape, nervation or 

 texture or in other particulars from the lemmas above 

 them. Frequently the first glume is smaller than the 

 second and often has fewer nerves. Sometimes this 

 reduction goes so far that the first glume is only a vestige 

 or it may be altogether wanting. Syntherisma shows 

 various stages in the elimination of the first glume, and 

 in Paspalum the first glume is generally absent or repre- 

 sented by a slight ridge. However there are species of 

 Paspalum in which the first glume may be present or 

 absent in the same raceme (P. distichum, Paspalum § 

 Dimorphostachys). The first glume in Eriochloa is usually 

 represented by a cup-shaped ridge below the normally 

 shaped second glume, but is present in certain species. 

 Both glumes are absent in a few genera, such as Reimaro- 

 chloa and Homalocenchrus. 



