328 ' THE BASIDIOMYCETES 



Kursanov [Arthur et al. (1929)] has studied the development 

 of telia among several genera, and his accounts indicate that the 

 developmental features resemble those of aecia and uredinia gen- 

 erally. Occasional genera are exceptional, such as Cystopsora, in 

 which the sori protrude from stomata and the teliospores appear 

 to be superficial, and Goplana mirabilis, occurring on Michelia 

 vehit'ma in Java, the teliospores of which are borne on a super- 

 ficial mycelium. 



Heteroecisin 



It is easily understandable that the early students of rusts should 

 regard the different spore forms as distinct genera, although in 

 1807 de CandoUe expressed the opinion that IJredo linearis and 

 Fiiccinia granmiis on wheat were one and the same but that they 

 chanored aspect with age. Persoon also suspected that the two 

 were stages of the same species. The Tulasnes {Ann. Sci. Nat. 

 Bot., ser. 4, 2:77-196) in 1854 decided that Uredo and Puccinia 

 were one and the same. They had noted several years earlier, in 

 connection with rose rust, the curious fact that Uredo rosae and 

 FhragiJiidiinn incrassatimi occur in the same sorus. Corda 

 (Icones Fimgorum Hiiciisqiie Cognitoriim 419, 1840) and Fries 

 {Sinmm Veg. Scand. 507, 1849) regarded the Phragmidium stage 

 as parasitic upon the Uredo stage. 



That the existence of a relationship between cereal rusts and 

 the presence of barberry had become thoroughly established in 

 the minds of farmers Ions: before de Barv's classical demonstra- 

 tion (1865) is shown by the fact that a law was enacted in France 

 in 1660 for the eradication of barberry, and that similar laws 

 \\'ere passed in several New England States between 1726 and 

 1766. Moreover in 1818 Schoeler in Denmark [Arthur et al. 

 (1929)] transplanted barberry bushes in rye fields and found 

 that rust became abundant, especially on those plants on the lee- 

 ward side of the barberry bushes. He also applied aeciospores 

 to rye leaves; after 5 days infections were evident, whereas his 

 control plants were rust-free. Nevertheless botanists were not 

 convinced of the genetic connections and continued to regard 

 the aecial stage as a different genus. 



In 1863 de Bary (1863) sowed sporidia of Uromyces appen- 

 diciilatiis on beans grown in the laboratory. Lesions appeared on 

 inoculated plants after 5 or 6 days, and spermogonia were ma- 



