TIMOTHY 147 



tions were totally destroyed. It closely resembles wheat 

 rust and attacks both the leaves and culms. The fungus 

 lives over winter on timothy in Virginia. Farther north- 

 ward teleutospores are abundantly produced. The rust 

 has been artificially transferred to oats, rye, tall fescue, 

 orchard-grass and Canada blue-grass, but wheat and barley 

 seem immune. 



In fields of timothy the rust seems never to be abundant, 

 and no injury worth while has been reported. On the 

 other hand, wayside isolated plants are often covered with 

 pustules, and apparently more so southward. The cup- 

 fungus (a3cidial) stage of this rust is not known. Experi- 

 ments in inoculating barberry plants, the secidial host of 

 the wheat rust, have been ineffective. 



Another disease which sometimes attacks timothy as 

 well as other grasses is a leaf smut ( Ustilago striceformis) . 

 It causes dark thickened lines on the leaf blades and 

 sheaths, which later burst open and become dusty from 

 the spores. This fungus is rather widespread, and has 

 been reported as damaging timothy in Wisconsin and in 

 Illinois. Severely attacked plants do not form heads. 



135. Variability. Timothy is a very variable grass, 

 as may easily be seen by examining individual plants where 

 they are growing scattered so as to permit the full develop- 

 ment of each. Some of the more marked varieties have 

 received names at the hands of botanists. Hays at the 

 Minnesota Experiment Station referred to a number of 

 the commoner variations in 1889, and Hopkins at the 

 West Virginia Experiment Station published more com- 

 plete studies in 1894. 



Clark has made a very full study of the variations ob- 

 served in 3505 isolated plants in the breeding nursery at 

 Cornell University Experiment Station. Some of the 



