AGKICULTUEAL SPECIES OF BENT GEASSES. 



19 



to contain, can not at present be identified with certainty or dis- 

 tinguished by the seed alone from American-grown Rhode Island 

 bent seed and colonial bent seed. Finally, the seed of carpet bent 

 or strictly stolonif erous forms of bent can not be recognized at present. 

 These phases of the subject are open to further investigation. 



The commercial kind of seed is often suggested and sometimes 

 determined by evidence of its source of production which appears in 

 the associated weed seeds and other seeds found in the sample. 

 Though certain kinds of weed seeds are found in both domestic and 

 imported seed, others are strongly suggestive either of domestic or 

 of foreign production. In this matter, the absence of certain kinds of 

 seeds is as helpful as the presence of others. 



THE SEEDS DESCRIBED. 



The following descriptions of the seeds of red top, Rhode Island 

 bent, and velvet bent are based chiefly upon their appearance under a 

 low-power compound microscope. When the distinguishing charac- 

 ters are recognized by this means the use of a high-power hand lens 

 enables one to recognize with a considerable degree of accuracy 

 the kinds in bulk quantity or in mixtures. A complete quahtative 

 and quantitative analysis requires the use of a compound microscope 

 and of laboratory methods. 



SEED OF REDTOP (AGEOSTIS PALUSTRIS HUDS.; AGROSTIS ALBA L. OF MOST BOTANISTS). 



Lemma 0.05 to 0.08 of an inch in length, lanceolate to lanceolate- 

 oblong in outline, somewhat ghsten- 

 ing, the longest lemmas exceeding the 

 grain about one-third their length, 

 the upper third or half of the lemma 

 translucent and silvery white, the 

 lower part opaque and often straw 

 colored, the apex usually distinctly 

 three angled, occasionally four an- 

 gled by the absence of the keel vein ; 

 the surface glabrous, very finely 

 and longitudinally striate; the awn 

 occasional, rudimentary, straight, 

 not spirally twisted, rarely exceed- 

 ing the apex of the lemma or bent 

 and twisted, arising near the apex 

 of the lemma, rarely as low as the 

 middle of the latter, often a mere projection from the surface (fig. 

 3, 4)'} tairs at the callus present or wanting; palet exhibiting two 

 types in appearance: (1) Not wrinkled, scarcely translucent, evi- 

 dently striate, usually equaling or exceeding the grain (fig. 3, 2) ; 

 (2) wrinkled, often shorter than the grain and between two-thirds 



Fig. 5. — Seeds of redtop (Agrostis palustris), 

 enlarged and natural size: In seeds a, b, and 

 c the palet is not wrinkled and covers the 

 grain. In seeds d and e the palet is wrinkled 

 and shorter than the darker grain, (The 

 natural size is shown at/.) 



