F.MKR(JKNCY ADAPTATIONS. '21 



Henn. .vot found in thiscountrv. The known hosts are Kli/imts cana- 

 dcnx'hs 'Ai\(\ K. r!,y'nurii,s, l»ut it seems to occur on other hosts. Whethei" 

 the forms on ditierent hosts can l)e transferred I'roni on(> to another 

 is not yet fully deterinined. 



The important fact now known, however, is thai tiie iii-edoform is 

 able to preserve the species over the winter without the intervention 

 of other stages, though it is possible that extensive propagation is 

 aided by other stages. Octol>er 28, 18i»T, fresh uredosori were observed 

 on Hhjimift canadensis at Manhattan, Ivans., and again in the same 

 locality on November 2. But as early in the spring as May 2»;, at 

 Lincoln Nebr., when there was yet but a small lieginning of vegetation, 

 the uredo had Imrst the epidermis of the host in grass plats at the 

 University farm. Previous to this the living uredo had been o)>served 

 in these plats practically every month of the winter. 



In other instances the uredospores of certain species are so very 

 abundant and the teleutospores so rare that there seems a probal)ility 

 that such species are carried over from summer to sunnner largely 

 through the uredo stage alone, though there is no absolute proof of 

 such a course. Two instances are particularly interesting— those of 

 the uredos of Pucclnla ernptiiiidn Ell. and Barth., and y^«r////V/ on 

 Panlvum autnmnah:'' The uredospores of these species begin to be 

 conspicuously abimdant al)out midsiunmer. but continue in consider- 

 able abundance until very late in autunm. The uredo of Panicum 

 aidumnale was found in germinating condition in Kansas up to Novem- 

 ber 3 in 1897. A water-drop culture of uredospores of this species 

 gave excellent germination in ten hours August 21, 189T. at Perkins, 

 Okla. The uredospores of Paeclnia cryptandrl were found in extreme 

 abundance in Oklahoma until October 11, 1897,' but in all cases with- 

 out any accompanying teleutospores. Often the uredosori had a fresh 

 appearance on portions of leaves that were (juite dead. 



EMERGENCY ADAPTATIONS. 



In connection with some culture experiments conducted at Lincoln, 

 Nebr., in the botanical laboratory of the State University, in February, 

 1898, a water-drop culture was made (February 3) of uredospores of 

 the above-mentioned Puccinia a'yptandri which had been collected on 

 October 8, 1897, at Perkins, Okla., and kept to date as herl)arium 

 specimens. A fair germination resulted in twenty-four hours. Spores 

 from the same collection were used on February 10 to inoculate seed- 

 lings of Sporohohis airoides^^ with the result of the appearance of two 

 rust spots by March 16. These spots may really have appeared much 

 earlier and been overlooked, as they were very small and the host 



« Perhaps a new species, needing further study. 



6 Apparently tliis same species of rust had already been collected on Sporobolus 

 airoides in the same locality where the collection from S. cnjplandri was made. 



