546 



PART III. — THE CLASSIFICATION OF PLANTS. 



bear no flowers in their axils and are known as the glumes (Fig. 

 355 g). Thus a spikelet consists of a main axis bearing two rows 

 of bracts of which the two first and lowest are barren, while the 

 succeeding ones bear each a flower in its axil, and beneath each 

 flower there is also a bracteole Tsuperior palea) belonging to the 

 floral branch itself. The inferior palese often have, either at the 

 apex or else borne on the midrib, a spinous process called the 

 arista or awn (Fig. 355 gr). 



The number of flowers in each spikelet varies, however, according 

 to the gen as ; often there is but one, the lowest, with rudiments of' 



Fig. 354. — Single-flowered spikelet of 

 Panicum miliaceum (mag.); C^ and C3 

 second and third glumes : D inferior 

 palea : E superior palea. 



Fig. 355.— a spikelet of Wheat dis- 

 sected (mag.) : X axis of the spikelet; 

 g glumes ; b^ b^ 63 b^ inferior paleae bear- 

 ing (gr) the awn ; b^ is sterile. JSi B^ B, 

 the flowers raised (as indicated by the 

 dotted lines) out of the axils of the in- 

 ferior paleae ; ps superior paleae ; a an- 

 thers ; / ovaries. 



others above it; if, however, only one of the upper flowers is de- 

 veloped, then the lower pale^ bear no flowers in their axils and 

 are regarded as glumes, several being therefore present in such a 

 case. The spikelets themselves are in many genera, e.g. Rye and 

 Wheat (Fig. 356 B), arranged in two rows on a main axis ; the 

 inflorescence may then be designated a compound spike (see p. 

 491) ; in most of the other genera the main axis of the inflor- 

 escence bears lateral branches which are slender, of various length, 

 and often branched again, and which bear the terminal spikelets ; 

 in this way a panicle is formed, as in the Oat (Fig. 356 A). This 

 may be either loose and spreading, with long lateral branches, or 

 compressed, with very short branches, e.g. Alopecurus. The 



