THE BOTRYOSE TYPE. 



149 



within. See Fig. 657-659 (683), where its morphology is ex- 

 plained and illustrated. Viewed as an inflorescence, it has also 

 been named a HYPAXTHODIUM. 



276. A Spike is a cluster of sessile (or apparently or nearly 

 sessile) lateral flowers on an elongated axis. It may be de- 

 fined by comparison, as a head with the rhachis lengthened 

 (indeed a young head often becomes a spike when older) , and 

 equally as a raceme with the pedicels 

 all much shortened or wanting. A 

 common Mullein and a Plantain 

 (Plantago, Fig. 290) are familiar ex- 

 amples. Two modifications of the 

 spike (or sometimes of the head) gen- 

 erally bear distinct names, although 

 not distinguishable by exact and con- 

 stant characters, viz. : - 



SPADIX, a spike or head with a 

 fleshy or thickened rhachis. The 

 term is almost restricted to the Arum 

 family and Palms, and to cases in 

 which the inflorescence is accompanied 

 by the peculiar bract or bracts called 

 a spathe (Fig. 269-271). But the 

 two do not always go together : in 

 Acorus and Orontium there is properly 

 no spathe to the spadix ; while in the 

 Iris family the bracts are said to form 

 a spathe, and there is no spadix. In Palms, the principal reason 

 for naming the inflorescence a spadix is its inclusion in a 

 spathe before anthesis. 



FIG. 288. A slice of Fig. 287, more enlarged, with one tubular perfect flower (a) left 

 standing on the receptacle, and subtended by its bract or chaff (!>); also one ligulate 

 and neutral ray-flower and part of another (c, c) : in rf, d, the bracts or leaves of the 

 involucre are seen in section. 



FIG. 289. Catkin of White F-irch. 290. Young spike of Plantago major. 



