140 REPRODUCTIVE ORGANS. CHAP. III. 



In the Grasses the common axis of the spike is 

 somewhat peculiar in its structure, and designated 

 by a proper name the Rachis, which is linear and 

 upright, as in Barley ; or flexuose, as in Darnel ; or 

 angular, as in Cock's-foot ; or jointed, as in Wheat; 

 or alternately furrowed, as in Rotbollia. 



SUBSECTION IV. 



Descrip- The Panicle. The panicle is an assemblage of 

 flowers supported upon a primary and terminal pe- 



tions. duncle or axis, that is irregularly divided into 

 secondarypeduncles, which are sometimes again sub- 

 divided into ternary peduncles. It is exemplified 

 in Bromus arvensis and Avenaflavescens, and may 

 'be regarded as resembling a sort of loose spike. It 

 is loose and spreading, as in Saxifraga umbrosa ; or 

 close and compact, as in Poa rigida ; or straddling 

 and divaricate, as in Prenanthe* muralis. It is said 

 to be simple if the primary peduncle is furnished 

 only with secondary peduncles, as in Bromus erec- 

 tus ; and compound if the secondary peduncles are 

 furnished also with ternary peduncles, as in Dacty- 

 Us glomerata. The spikelets are either sessile, as in 

 Poa procumbens ; or pedicled, as in Poa nemoralis. 

 (PI. V. Fig. 4.) They are also either erect, as in 

 Bromus erectus ; or nodding, as in Bromus asper ; 

 or turned to the one side, as in Festuca rubrq. 



