THE GRASS FAMILY 



13 



In the spikelets of sedges the florets are commonly, 

 but not always, spirally arranged, there never is a 

 palea, and the fruit is an achene or nutlet. [The 

 ''seeds" of buttercups and 

 mints are achenes or nut- 

 lets.] 



In grasses specialization 

 takes place mostly in the 

 spikelet. By its vegetative 

 characters we know a given 

 plant to be a grass, but it 

 is by its spikelets and their 

 arrangement that we know 

 what kind of a grass it is. 

 The genera of grasses and 

 the groups of genera called 

 tribes are based on the 

 structure of the spikelets 

 and their arrangement in 

 the inflorescence. 



Before studying the spike- 

 let we must observe the 

 relatively few specializations of the vegetative parts- 

 As in other plants, stems or parts of stems may be 

 underground. These underground stems (rhizomes, 

 or rootstocks) are borne at the base of the main culm 

 under the earth, spread out hoiizontally, and in due 

 time send up shoots which form young plants at a 

 distance from the parent. Sod-forming grasses have 

 this kind of underground stem. Kentucky blue- 



FiG. 8. Generalized spikelet. 



