ON RUBIACE^ 163 



leaves on healthy plants on the 26th of April, removing them after a time ; 

 nevertheless the experimental plants showed both uredo- and teleutospores 

 on May 16th. Their mycelium is localised, but that of the secidium 

 permeates the whole plant ; it is a disputed point whether it perennates 

 in the rhizome or not ; Plowright affirms, Fischer denies this, and Bubak 

 thinks it probably not perennial (Centralbl. fur Bakt. 2. xvi. 150). 

 Fischer records and figures abnormal three- or four-celled teleutospores. 



The distinctions between this species and P. Adoxae lie not only in 

 the presence of the secidium and uredo, but also in the appearance 

 and character of the teleuto-sori. In P. albescens these are widely 

 scattered and mostly single, and only follow the ascidium towards the end 

 of May — in P. Adoxae they are crowded in larger groups, on more or less 

 deformed parts of the plant, and can be found as early as April or even 

 March ; moreover there are no uredospores in them. 



An secidium on Adoxa is found in North America, but it has been 

 said (Dietel, 1895) that teleutospores have only once been seen there on 

 that host. On that account Dietel considers that the a^cidium is able to 

 reproduce its own spore-form. This is contradicted by Bubak's experi- 

 ments and, since P. argentata is common in North America, it is more 

 probable that the secidium on Adoxa found there is not JEcidmm 

 albescens, but belongs to P. argentata. Bubak, in fact, considers that this 

 is the case with most of the records of P. albescens. He says that the 

 iecidium of P. argentata has golden-yellow spores, and that he has met 

 with the true JEcidinm albescens only from Yorkshire and Baden. I do 

 not quite share this view : I have found teleutospores, apparently not 

 mixed with uredospores, in mid-April, on the same plant on which were 

 abundant secidia with golden-yellow spores. Thei'e are three possible 

 explanations of this occurrence : either (1) it was P. albescens with deep- 

 coloured spores, or (2) there were on the same plant P. Adoxae and the 

 secidiurn of P. argentata (which is a very rare species in Britain), or (3) all 

 the distinctions usually given must be upset. Which is the true explana- 

 tion, future experiments alone can decide. 



36. Puccinia Asperulae-odoratae Wurth. 



Puccinia Asperulae Fckl. Symb. Myc. p. 56 p.p. 



P. punctata Lk. ; Sydow, Monogr. i. 213 p.p. 



P. Galii Plowr. Ured. p. 143 p.p. Fischer, Ured. Schweiz, p. 332, 



f. 246 (see ibid. p. 555). 

 P. Asperulae-odoratae Wurth, Centralbl. f. Bakter. 2. xiv. 314, 



f. 9—10. 



sEcidiospores. iEcidia hypophyllous, in little clusters, sur- 

 rounded by a paler zone, cup-shaped, with a slightly projecting 



11—2 



