Manchester Memoirs, Vol. Ivii. (191 3), No. 



XI. On some relations between Puccinia malvacearum 

 (Mont.) and the tissues of its host plant 



{Althaea rosea). 



By Wilfrid Robinson, B.Sc. (Lond.)- 



( Communicated by Professor IV. H. Lang, M.B.., D.Sc, F.P.S ) 



( Read April 22nJ, igij- Received for publication /line 6th, igrj.) 



This paper deals with some features of the Hollyhock 

 rust, the disease caused by Puccinia malvacearum, and 

 especially with the relations between the tissues of the 

 host and the parasitic fungus. This disease is common 

 in market gardens near Manchester, and experimental 

 work on the conditions of infection is in progress. A 

 more detailed knowledge of the histological features of 

 the diseased regions was a necessary preliminary, and the 

 present paper deals with this portion of the work. 



Puccinia malvacearum has been studied by a number 

 of investigators, and the main features of its life-history 

 are well known. It was first described by Montagne in 

 1852, and since that date Kellerman, Rathay, Tauben- 

 haus, Eriksson and others have studied its morphology 

 and life-history from various points of view. It occurs 

 chiefly on Althaea rosea and Malva sylvestris, but has been 

 found to attack many other members of the Malvaceae. 

 The sori of teleutospores occur abundantly on the lower 

 surfaces of the leaves and also on the petioles, stems, 

 bracts, sepals and even on the young fruits. On the leaves 

 the sori are at first circular but often become confluent, 

 whilst on the stem and petiole they are elongated and 

 elliptical in outline. The teleutospores, on reaching 



Sept. jth, igij. 



