20 



INVESTIGATIONS OF RUSTS. 



there exists a similar hardiness of the uredo, of which cases the fol- 

 lowing will be discussed here: 



Uredo of Kentucky Bluegrass Rust (Puccinia poarum Niels.). 



The writer has known for some time that the uredo stage of the blue- 

 grass rust is able to pass the winter alive and in germinating condition 

 during any season as far north as Lincoln, Nebr., but additional evi- 

 dence has been obtained from time to time. At the same time it is sig- 

 nificant that there is no record that the teleutospores have ever been 

 found, except in one instance, at the above-named place. In fact, few, 

 if any, uredoforms so hardy as this one exist in this country. On 

 February 1, 1893, this uredo was still alive in the vicinity of Man- 

 hattan, Kans. Eveiy month of the \ T ear it exists alive and growing in 

 great abundance everywhere about Washington, D. C. On March 2, 

 1898, it was found fresh on green leaves of the host at Lincoln, Nebr. 

 On the same spot of ground it was still growing and spreading rapidly 

 on Ma} r 8 of the same year. Host plants were transplanted that day 

 into a greenhouse, where the rust continued to increase rapidly. As 

 would now be supposed, the rust is sharply limited to its one host, 

 Kentucky bluegrass. The results of the following cultures may be 

 given in evidence. 



Table IV. — Culture experiments with the uredo of Kentucky bluegrass. 



Date. 



Locality. 



Origin of inoculat- 

 ing material. 



Plant inoculated. 



Period 

 of incu- 

 bation 

 in days. 



Result. 



Jan. 16,1893 



Manhattan, Kans . 

 do 



Poa pratensis 



Wheat 



18 

 18 

 16 



11 



11 

 13 



13 



18 



10 





Do 



Oats 



Do. 



Dec. 21, 1896 



Jan. 22,1897...: 



Washington, D.C.. 

 do 



Rye (Uredo rubigo- 



vera) . 

 Wheat ( Uredo gra- 



minis). 



Poa pratensis 



do 



Do. 

 Do. 



Do.. 



do 





Do 



Feb. 1,1897 



do 



Rye ( Uredo rubigo- 



vera). 

 do 



Poa pratensis 



Poa nemoralis 



Poa pratensis 



do 



Do. 



Do 



do 



Do. 



Feb. 13, 1897 



do 



Wneat( Uredo rubigo- 

 vera) . 



Do. 



Feb. 25, 1897 



do 



Success. 













Uredo of Puccinia moxtaxensis Ell. 



This is, in some respects, one of the most interesting of grass rusts. 

 It is one of the " covered rusts," and is, indeed, so far covered that it 

 is often entirely overlooked by collectors. The uredosori are very 

 uniform in size and are exceedingly small, it being necessary often to 

 examine them, or even find them, with a hand lens. They are ellip- 

 tical in shape and placed end to end in long, narrow, } T ellow striae 

 between the veins of the leaf. The teleuto stage is so far hidden as 

 to be detected only by a faintly darker color beneath the leaf epi- 

 dermis. The rust is the most nearly like P. glumarum Eriks. and 



