CHAP. II. 



BRACTS. 



125 



spadix, large coloured bracts, in which the spadix, dming 

 aestivation, is wholly enwrapped, and which may perhaps per- 

 form in those plants the office of corolla. This is called the 

 spathe {Jig. 85.).' Link considers it a modification of the 

 petiole! {Elemejita, p. 253.) 



fiS 



The most remarkable arrangement of bracts takes place 

 in Grasses, in which they occupy the place of calyx and 

 corolla, and have received a great variety of names from 

 different systematic wi-iters. In order to explain distinctly 

 the application of these terms, I must describe with some 

 minuteness the structure of a lociista or spikelet, as the partial 

 inflorescence of Grasses is denominated. Take, for example, 

 any common Bromus; each spikelet will be seen to have at its 

 base two opposite empty bracts {Jig. 68. J), one of which is 

 attached to the rachis a little above the base of the other : 

 these are the glumes of Linnaeus and most botanists, the gluma 

 exterior or calgcinalis of some writers, the tegmen of Palisot 

 de Beauvois, the lepicena of Richard, the ccetonium of Trinius, 

 and, finally, xhe jjeristachyrim of Panzer. Above the glumes are 

 several florets sitting in denticulations of the rachis {Jig. 68. c) : 

 each of these consists of one bract, with the midrib quitting 

 the blade a little below the apex, and elongated into a bristle 

 called the aion, heard, or arista, and of another bract facing 

 the first, with its back to the rachis, bifid at the apex, with no 

 dorsal vein, but with its edges inflexed, and a rib on each side 

 at the line of inflexion (fig, 68. a). These bracts are the 

 eorolla of Linnaeus, the calgx of Jussieu, the perianthinm of 



