OF TENNESSEE 61 



the Timothy, 3-4 spikelets are similarly arranged to a consert- 

 ed cylindrical spike. But if these single clusters are more or 

 less distant from another, like in the Sweet Vernal grass 

 (Anthoxantum ocloratum) it is said to be panicled-spiked. 

 The barley bears a bilateral spike, spikelets in threes on each 

 side. Hordeum hexastichum. In the Crab grass (Digi- 

 taria or Panicum sanguinale) the spikelets are arranged to 

 one side of the rachis ; the rachis may also be feathered 

 on the back like in the related genus Paspalum. In the 

 barn-yard grass the spikelets are imbricated (like the shin- 

 gles on a roof) on a one-sided spike. 



To analyze so small an object as the spikelet of the Tim- 

 othy, or other yet more minute and delicate species, some 

 care and patience are required. 



The spikelet should be moistened first with a little water, 

 after being placed upon a slip of glass, then the parts spread 

 in a manner to expose the interior structure. The moisten- 

 ing prevents the flying away of the tiny membranes when 

 they are dissected or distended with a fine knife or a pair 

 of sewing needles. A lens to magnify the object is indis- 

 pensable. 



First two pairs of membranaceous leaflets are conspicu- 

 ous. vThe lowest pair is called " glumes." They are oppo- 

 site one another, but not exactly upon one "and the same 

 level. There is always an upper glume and a lower glume, 

 and the observance of their mutual relations is of great import- 

 ance. Sometimes they are nearly of one size, like in this 

 instance, but generally one is larger, often out of all propor- 

 tion, or either is minute, abortive or wanting, awned or va- 

 riously shaped, or represented by a bristle-like 'organ caljed 

 an awn. (Beard.) They are boat-shaped (carinate), ciliate 

 on the back (beset with short, bristly hairs), pointed and 

 tipped with a short bristle. Glumes serve as the common 

 involucre for the upper and interior part or parts of the 

 spikelet. 



