4 BULLETIN 461, U. S. DEPARTMENT OF AGRICULTURE. 



The collar is a narrow band marking the place where the blade 

 and the sheath join. It is often scarcely differentiated, but usually 

 has a different color from either the blade or the sheath. In some 

 cases the collar is a continuous band extending from one margin of 

 the leaf to the other, but in others it is divided into two parts by 

 the midnerve. The margins of the collar in some grasses are wavy, 

 in others straight ; some are hairy, others entirely glabrous or hairless. 

 In some grasses one side of the collar is higher than the other, giving 

 it a spiral appearance. 



The auricles are earlike or clawlike appendages projecting from 

 the collar or the angles at the top of the sheaths in a few grasses. 

 They may be small or large, hairy or free from hairs. Often they 

 clasp the stems more or less, especially when young, but as they 

 become older and dried they may turn away from the stem. Only 

 the narrow clawlike auricles are considered in the analytical key. 



The flowering parts are not used in this classification. If the 

 grass has reached the blooming stage it can be more easily identified 

 by using one of the many books on the subject. 



The word glabrous is used to mean free from hairs. 



HOW TO USE THE KEY IN IDENTIFYING GRASSES. 



The analytical key (pp. 6-9) is composed of pairs of opposing 

 statements. The first statement of each pair is designated by a letter, 

 A, B, C, etc.; the second one has the same letter as the first, but 

 repeated, as AA, BB, CC, etc. The statements constituting each 

 pair may be close together, as "A. Auricles narrow and clawlike, 

 clasping the stems more or less," and "AA. Auricles wanting, or at 

 least not narrow and clawlike," or they may be separated as " B. Col- 

 lar hairy," and " BB. Collar not hairy." If a specimen does not 

 agree with the first statement, all intervening headings should be 

 passed over at once until the corresponding second statement which 

 does apply is reached. 



One of the best ways to learn to use this key is to get specimens 

 of young grasses and endeavor to trace them. Take, for example, 

 orchard grass. The first thing that must be done is to determine 

 whether the leaf is folded (fig. 4, A) or rolled (convolute; fig. 4, 

 B and C) in the bud. This is best done by cutting across the young 

 shoot with a sharp knife and examining it with a lens. Another 

 method of determining this point is to strip off the leaves carefully 

 until the youngest is exposed and then examine with a lens. With 

 the larger grasses it is easy to decide whether the leaves are folded 

 or rolled in the bud, but with the finer sorts, such as the bent grasses 

 or the fescues, it is sometimes difficult. The leaf in the case of 

 orchard grass is folded in the bud, so it will come in Group I. 

 The first line of the key, marked " A," reads " Auricles 



