ORCHARD-GRASS, OAT-GRASS, BROME-GRASSES 179 



year the percentage of each grass. The percentage o f 

 orchard-grass each year was as follows : 



The percentage increase of the orchard-grass due to 

 the gradual disappearance of the other grasses was more 

 marked in the shaded than in the unshaded area. 



180. Variability. Orchard-grass is exceedingly vari- 

 able, not less so than timothy. Numerous varieties can 

 easily be selected anywhere from thin fields and from the 

 roadsides. Cross-pollination is the rule so that such 

 individual plants usually give rise to diverse progeny. 

 There can be no question that pure strains much superior 

 to the ordinary mixed progeny can easily be isolated. It 

 is doubtful, however, if the importance of this grass in the 

 United States is sufficient to justify selection and the care 

 necessary to keep strains pure. 



181. Advantages and disadvantages. To illustrate 

 the strong and weak points of orchard-grass it may be 

 compared with timothy. Orchard-grass is better adapted 

 to conditions southward and less so to those northward; 

 it is less well suited to being grown in pure cultures, owing 

 to its bunchy habit ; it can be cut for hay much earlier ; 

 it becomes woody after full bloom much more rapidly and 

 markedly ; the cost of seed per acre is about five times as 

 large ; the spring growth is more abundant and much 

 earlier ; the aftermath is much greater, often producing 

 a second crop of hay ; the plants are more persistent both 

 in meadows and pastures. 



