ON GRAMINE2E 25^ 



the forms which grow upon wild grasses ; according to Eriksson this is 

 absolutely true of his " f. sp. Tritici," but Carleton found that the uredo 

 from wheat would infect certain wild grasses and that the uredo from 

 some of them, in turn, would infect the wheat. Most of these races can 

 equally infect the Barberry ; yet Wheat-Rust abounds in South Africa, 

 Australia and in parts of India, where no species of Berberis are indigenous. 

 McAlpine in particular finds P. graminis on 27 species of Graminea?, yet 

 he was unable to infect the Barberry-plants imported from England, even 

 though wheat planted closely around them was covered with the Puccinia. 

 He comes to the conclusion that the Wheat-Rust of Australia may be a 

 biological race which has lost the power of producing recidia owing to the 

 absence of its secidial host. According to the evidence at present available, 

 this seems also to be the case with other species, e.g. the aacidial host is 

 not known in Australia for P. Agrostidis, P. bromina, P. Festucae, P. Lolii, 

 and especially P. Poarum. The latter case is the most striking, since the 

 Coltsfoot does not exist in Australia, and the uredospores on Poa have 

 been found there all the year round. 



The only practicable remedy for this disease is to plant seeds of 

 varieties which have been shown to be immune : a certain progress has 

 already been made by Professor Biffen and others in the production of 

 these, and McAlpine mentions a variety, " Rerraf," which has been found 

 to be rust-resistant in many of the Australian States, though it lost that 

 power when transferred to other countries. In the year 1889, which had 

 a wet and "muggy" spring, the loss due to rust for the whole of Australia 

 was estimated to be between two and three million pounds sterling. 



Distribution : In every country of the world. 



IIS. Puccinia coronata Corcla. 



sEcidium crassum Pers. Syn. Fung. p. 208 p.p. Cooke, Handb. 



]). 538; Micr. Fung. p. 196 p.p. 

 jE. Frangulae Schum. PI. Sail. ii. 225. 

 Puccinia coronata Corda, Ic. Fung. i. 6, pi. 2, f. 90. Cooke, Handb. 



p. 494; .Micr. Fung. p. 203, pi. 4, f. 60—2. Plowr. Ured. 



[». 163 p.p. Sacc. Syll. vii. 623 p.p. Sydow, Monogr. i. 699. 



Fischer, Ured. Schweiz, p. 373, f. 270. 



Spermngones. Epiphyllous or amongst the secidia. 



sEcidios pores. yEeidia hypophy lions or on the petioles, in 

 roundish groups or irregularly scattered,, on yellow or purplish 

 spots, producing distortion especially of the petioles, cylindrical, 

 with a white torn revolute margin ; spores very delicately 

 verruculose, orange, 16 — 25 x 15 — 20 p,. 



Uredospores. Sori amphigenous, but mostly epiphyllous, 



