AGKICULTUEAL SPECIES OP BENT GEASSES. 



17 



1 2 3 4 



Fig. 3. — Hulled seeds of redtop (Agrostis palustris), enlarged, illustrating 

 the general structure of seeds of bent grasses: 1, Back of the lemma; 

 a, the keel vein; 66, the marginal veins; c, the callus. 2 and 3, The 

 opposite side of the seed; d, the palet, not wrinkled and covering the 

 grain; e, the palet, wrinkled and shorter than the grain. 4, Back of a 

 lemma ha\dng an awn (/) and intermediate veins (gg). - 



DISTINGUISHING THE SEEDS. 



In consequence of the close relationship existing between redtop 

 and the other bent grasses, their seeds are very similar in appearance 

 and are readily mistaken, one kind for another, unless they are 

 examined critically with the aid of a low-power compound microscope 

 or a high-power 

 hand lens. 



The distinguish- 

 ing characters of 

 the minute seeds of 

 redtop and other 

 bent grasses which 

 are of practical 

 value in recogniz- 

 ing the species are 

 found in the seeds 

 when freed from 

 the outer envelop- 

 ing chaff (fig. 3). This chaff (fig. 4) readily separates from well- 

 matured seeds. In immature seeds the chaffy scales tend to cling to 

 each other and to the inclosed seed. An unnecessary proportion of 

 chaff usually constitutes a considerable part of the bulk of Rhode 



Island bent, colonial bent, and 

 South German mixed bent seed. 

 Domestic redtop is sold with the 

 chaff present as "chaffy" redtop 

 and free of the chaff as "fancy," 

 "hulled," or "recleaned" redtop. 

 An opinion on the kind of seed 

 found in a given sample and its 

 probable source is based upon (1) 

 the structural characters of the 

 seed, which show its kind, and (2) 

 the impurities found in the sample, 

 such as other grass seeds, weed 

 seeds, and chaff, which usually 

 indicate the source of production. 



Fig. 4.— Chaff, or hull, of redtop seed: a, Whole 

 spikelets usually devoid of seed in "chaffy" 

 grades; 6, separated scales of the same; a and 6 

 represent the outer chaff of the seed. (Enlarged. ) 



GENERAL STRUCTURE. 



Freed from the two outer chaffy scales, called the glumes, an indi- 

 vidual seed of redtop or of the other bent grasses consists of a grain 

 lying between two unequal, more or less inclosing scales (fig. 3, 

 1 and 2). The larger scale, which exceeds the length of the grain, 

 is termed the lemma. The smaller is termed the palet or palea. 

 The palet is especially important in distinguishing the kind of seed. 

 WhUe the palet varies somewhat in the same kind of seed, it differs 



