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



Since tall meadow-grass is entirely restricted to wet soils, the root 

 system is not extensively developed, and it requires a relatively high 

 amount of moisture to supply its needs. In its typical habitat it 

 wilted beyond recovery when the soil water was reduced to from 

 12 to 14.5 per cent. 



The average period of flower-stalk production extends over about 

 three weeks, beginning about July 10, while by August 1 most of the 

 stalks have been sent forth. The seed begins to ripen about Au- 

 gust 20, and by September 10 the crop is practically all matured 

 and disseminated. Seeds are dropped immediately upon ripening. 



The germinative power of the seed crop, as tested in 1908, gave 

 an average of 85 per cent, and since reproduction of this species seems 

 to be generally good, it is probable that the seed has a high average 

 vitality. 



Tall meadow-grass (Plate XX), like a number of other species 

 with a high-water requirement, supplies only a limited amount of 

 forage. It is relished by all classes of stock, and is probably most 

 valuable as forage during August, since it is then less succulent than 

 earlier in the season. Up to August 1 the flower stalks are eaten 

 nearly to the same extent as the leaf buds, but after that period they 

 become somewhat tough and are not usually eaten by sheep. Horses 

 and cattle, however, continue to consume the entire plant until much 

 later in the season. 



Another species, P. pauciflora, very commonly associated with 

 tall meadow-grass, has similar distribution and habits. P. pauciflora, 

 however, does not occur as abundantly and, consequently, is not as 

 valuable as a forage plant. It is readily distinguished by having 5 

 nerves on the lemma instead of 7, as in the case of tall meadow grass. 



BIG BUNCH GRASS. 

 (Agropyron spicatum.) 



The grass tribe, Hordeae, to which this and the following five 

 species belong, is of high importance in the West. The genus 

 Agropyron contains about 40 species, more than half of which are 

 found in the United States. Of these, many are highly valuable 

 for hay and forage. 



Big bunch grass or blue bunch grass, as it is sometimes called 

 because of the characteristic blue-colored culms or stems, is a peren- 

 nial with deep fibrous roots. The culms, smooth and covered with 

 " bloom," attain a height of about 12 to 18 inches in dry situations 

 where this grass characteristically occurs, while in deep rich soils of 

 abundant moisture a height growth of about 30 inches is sometimes 

 made. The leaf blades, about half the length of the culm, are mainly 

 basal and produced in abundance. They are flat when green, but 

 slightly rolled inwardly when the plant is air dry or suffering for lack 



