4 BULLETIN 545, U. S. DEPARTMENT OF AGRICULTURE. 



The Arctic-alpine zone (alpine-meadow association), owing to its 

 small carrying capacity and inaccessibility, has little or no value for 

 grazing, and the character of its vegetation need not be discussed. 



On the Wallowa National Forest the vegetation which furnishes 

 the greater part of the forage is distinctly herbaceous. It consists 

 primarily of grasses, sedges, and rushes, with a fair representation 

 of nongrasslike species commonly termed "weeds." While the 

 species are numerous, about 50 furnish virtually all of the range forage. 



GENERAL MORPHOLOGY OF GRASSES. 



In the discussion of the individual species it will be necessary to 

 refer to specific characters in a general way as a means of distin- 

 guishing one species from another. It is essential, therefore, that 

 the reader have a clear conception of what a true grass is. The 

 stems or culms are usually hollow except at the joints {nodes). 

 The leaves consist of two parts, the sheath, which surrounds the culm 

 usually like a split tube, and the blade. The minute flowers are 

 arranged in spikelets consisting of a shortened axis (the rachilla) and 

 from two to many 2-ranked scales, the lower two of which (the 

 glumes) are empty, while each of the others (the lemmas) bears in 

 its axil a flower inclosed in a 2-nerved scale (the palea). Lemma, 

 palea, and flower, together, are termed the floret. The spikelets may 

 be sessile (without a footstalk) along a jointed axis (the rachis), as 

 in wheat and rye, the whole constituting a spike, or on little stems 

 (pedicels) and arranged in panicles, as in mountain bunchgrasss and 

 smooth bromegrass. The head of timothy is a panicle with the 

 branches and pedicels greatly shortened. This is called a spikelike 

 panicle. Sometimes the lemmas or the glumes bear bristlelike 

 appendages termed awns. The "beard" of barley consists of awns. 



Plate II has been prepared to illustrate characters which will fre- 

 quently be alluded to in the following discussion. In this illustration 

 cultivated timothy (Phleum pratense) and smooth bromegrass 

 (Bromus inermis) are used because they are well known to stockmen 

 and because they represent the morphology of two distinct and 

 important tribes of grasses. 



IMPORTANT SPECIES. 



GRASSES. 



The grass family (Poaceox) contains about 3,500 known specie?. 

 Tiny vary in size from small, mosslike individuals in the extreme 

 Polar regions to treelike growths of a hundred feet or more in the 

 Tropics. As a wholo, no family of plants enjoys a wider distribu- 

 tion or grows in a greater variety of soils, and no other family 

 is as important economically. From a grazing viewpoint the 

 grasses are more valuable, all localities considered, than all other 

 plants put together. 



The general taxonomie characters of grasses are shown in Plate II. 



