GRAMINE^ (POACE^), GRASS FAMILY 87 

 CEREALS 



Cereals are those grasses which are grown for their grain. 

 Buckwheat is sometimes considered a cereal because its 

 fruit (achene) is ground into flour, but it is not so considered 

 here. 



Buckwheat, flax, and others, which are often raised for 

 their seed or fruit, but are not grasses, are discussed wherever 

 they happen to come in the botanical order of treatment 

 followed here. 



Key to Groups (Genera) of Important Cereals^ . 



1 Whai is a "key," and how is it used? Throughout the following pages 

 there will be a number of "keys." A "key" is a convenient form for dis- 

 tinguishing one plant from another, or one plant group from another. It 

 presents in concise form the principal differences between the plants con- 

 sidered. It also enables one to determine the proper classification of an 

 unknown plant. Most of the "keys" in the following pages are "artificial," 

 that is, the characters used are obvious ones. The "keys" herein are con- 

 structed on the dichotomous plan, i.e. by twos. The entire number of groups 

 under consideration, whether these be species, genera, families, or higher 

 divisions, is first divided into two subgroups; each of the subgroups is sub- 

 divided into two groups, and so on. The alternatives are equally indented 

 on the page. In the key to the genera of cereals, they are first divided into 

 two large groups, the first including Zea, Oryza, Andropogon and Millets; 

 and the second, Avena, Secale, Triticum and Hordeum. It is seen that those 

 genera of the first group have "spikelets falling from the inflorescence entire 

 ..." while those of the second group have "spikelets falling from the in- 

 florescence without the glumes. . . " Each of the two large groups 

 is again separated into two subdivisions. For example, the genera Avena, 

 Secale, Triticum and Hordeum, are subdivided on the basis of their inflores- 

 cences. Avena has a panicle inflorescence, while Secale, Triticum, and Hor- 

 deum have a spike inflorescence. 



Let us suppose that we have a cereal in hand, the genus of which we wish 

 to determine. First of all, it would be necessary to decide whether the 

 "spikelets fall from the inflorescences entire . . . ;" or "spikelets fall 

 from the inflorescence without the glumes . . . ;" if it has the characters 

 of the second alternative, we know it is either oats, rye, wheat or barley. 

 Should the specimen in hand have a spike inflorescence, oats is eliminated 

 from consideration, and the plant must be either rye, wheat or barley. If, 



