EXERCISE XXXI. 

 CHARACTERISTICS OF GRASS "SEEDS." 



Supplies for a Laboratory Section of Twelve. Twelve small vials of each of the following: orchard grass, 

 brome grass, meadow fescue, red top in chaff, Kentucky blue grass, perennial rye, timothy, cheat or chess. 

 Twelve tripod magnifiers. 



INTRODUCTION. The ability to identify on sight the "seeds" of our valuable, small- 

 seeded forage crops and to recognize with certainty the more common adulterants and im- 

 purities in such seeds are matters of much importance to farmers. Important as such knowl- 

 edge is, however, it is an. unfortunate fact that few farmers have it. Luckily, all small-seeded 

 forage crops, with a few but important exceptions, like rape, are either grasses or legumes. 

 This fact simplifies matters very much. Reasonable ability in identifying the more common 

 forage crop "seeds" is therefore a matter of a little close study and some practice. 



The identification of grass "seeds" is based upon such points as awn, rachilla, pubescence, 

 shape, size, and color. If the student has carefully studied threshed oats, barley and wheat, 

 there is practically no structural part about a grass "seed" with which he is not already 

 familiar. 



1. Awn. (a) Which grass "seed" is distinctly awned? 



(b) Which one has a very short awn (awn pointed)? 



(c) Which one, while normally awnless, is in rare cases awn pointed? 



(d) Which five are awnless? 



2. Rachilla Joint, (a) On which six is the attached joint of the rachilla easily seen? 



(b) On which two is there no rachilla»joint? 



(c) Which three have a rachilla that suddenly enlarges at the end into a sort of plate 

 or flattened knob? 



(d) Which three gradually enlarge toward the end of the rachilla — ending without pro- 

 nounced plate or knob? 



(e) Which of the foregoing three are decidedly slanting at the free end? 



(f) Which of the foregoing three is flattened in cross section and slants very little at 

 the free end? 



(g) Which has a strongly curved rachilla? 

 (h) Which has a strongly pubescent rachilla? 



3. Bristles, (a) Which one has a row of spines along its keel (the sharp ridge on the 

 side opposite the palea) toward the tip? 



(b) Which one has a row of short spines all along from base to the tip of what appears 

 to be the keel? 



4. Shape, (a) Which one is rather flat? 



(b) Which one is rather canoe-shaped (strongly in-rolled)? 



(c) Which one is very short and plump? 



5. The Tip. (a) The tip of which one usually appears particularly ragged and frayed? 

 (b) In which one does the tip have about a fourth of a twist to right or left? 



6. Size, (a) Which two, regardless of shape, are rather large? 

 (b) Which three are rather small? 



7. Color, (a) Which three are rather brown? 



(b) Some of the "seeds" of what grass are silvery white in color? 



99 . . : 



