48 



Mr. C. B. Plowright. 



[Nov. 22, 



of botli these Puccinice upon Rumex hydrolapathum (the species Winter 

 originally experimented with), and found that the iEcidium was only- 

 produced from P. magnusiana. Winter,* in the " Kryptogamen- 

 Flora," now in course of publication, accepts Schroter's statement, 

 and gives as the secidiospores of Puccinia magnusiana, not only the 

 ^Ecidium on Rumex hydrolapathum, but also on R. crispus, conglomeratus, 

 ohtusif alius, and acetosa, and adds a note to the effect that the ^Ecidium 

 upon Rheum officinale has probably the same life history. 



Personal Investigations. — In 1882 I performed a number of experi- 

 mental cultures for the purpose of personally observing the life 

 history of the hetercecismal uredines generally. For instance, upon 

 two occasions, a handful of reed leaves and stems were laid upon 

 healthy plants of Rumex conglomeratus ; after a time these plants 

 became affected with 2Ecidium rumicis, and I naturally concluded 

 that this had arisen from the spores of Puccinia magnusiana which. 

 I had observed upon the reeds employed. Afterwards, upon three 

 separate occasions, when I had become more expert in performing* 

 these experiments, I applied the spores of P. magnusiana to other 

 plants of Rumex conglomeratus and once to R. obtusifolius, but without 

 producing any ^Ecidium. Subsequent research has rendered clear 

 that on the reeds used in my first two experiments, both Puccinioe 

 were present. Being desirous of finding, if possible, the secidiospores 

 of P. phragmitis, if this plant possessed any, I this year placed its 

 spores upon various Ranunculi (R. repens and Ficaria), but without 

 any result. It then occurred to me that Winter might be in error in 

 affiliating all the dock secidia to P. magnusiana, and that perchance on 

 some of them the Eecidiospores of P. phragmitis might occur. This 

 presumption was favoured by the fact that the sedicia we have been 

 in the habit in this country of lumping together as JEcidium ranuncu- 

 lacearum include two species which, although resembling each other 

 very closely in appearance, have distinct life histories. I, therefore, 

 on 16th May (1883), placed sporesf of Puccinia phragmitis upon 

 Rumex crispus, and in due time obtained an abundant crop oiutEcidium 

 rumicis. On 16th June, when the JEcidium was perfectly mature, 

 I placed some of its spores upon two plants of Phragmitis communis, 

 where it produced, first the uredo (distinguished from the uredo of 

 P. magnusiana by the absence of paraphyses), and later the perfect 

 Puccinia phragmitis. Subsequently plants of Rumex hydrolapathum, 

 obtusifolius, conglomeratus, and Rheum officinale, were successfully 

 infected with Puccinia phragmitis spores ; whereas the infection of 

 other specimens of these plants with Puccinia magnusiana was in all 



* Winter, " Kabenhorst's Kryptogaraen-Flora," 1881, p. 222. 



f The word spore is here employed in the sense that De Bary employs it,„ 

 namely, to indicate the body produced by the promycelium of the teleutospore. I 

 have elsewhere spoken of these spores as "promycelium spores." 



