Vol. xiv. No. i— Botanical Gazette— July, 1889. 



Notes on cultures of (Tynmosporangium made in 1887 and ISss. 



ROLAND THAXTER. 



In a paper "On certain cultures of Gymnosporangium, 

 with Notes on their Roesteliav' published in the proceedings 

 of the American Academy of Arts "and Sciences (vol. xxii, 

 p. 259), I gave the results of experiments undertaken in the 

 spring of 1886, at the suggestion of Prof. Farlow, with a 

 view to determine, if possible, the connection existing be- 

 tween the various species of Gymnosporangium and Roes- 

 telia found in the vicinity of Boston ; and since the publica- 

 tion of the paper referred to, similar cultures have been con- 

 tinued yearly, the results of which are given in the present 

 article. In order, however, to make myself intelligible, it 

 may be expedient to summarize my previous results, the 

 more so since my later cultures necessitate some modification 

 of the views then expressed concerning one at least of the 

 Roestelice obtained. 



Having in the cultures of 1886 succeeded in obtaining 

 aecidia from five of the seven species of Gymnosporangium 

 common in New England, it became necessary to determine 

 with some accuracy to which of the numerous forms of Roes- 

 telia these aecidia severally belonged ; and to this end a large 

 number of specimens were examined, including numerous 

 examples from European exsiccati, which the kindness of 

 Prof. Farlow placed at my disposal. As a result of this ex- 

 amination, it became evident that the opinions generally ac- 

 cepted in this country concerning the identities existing 

 between the American and European forms were erroneous 

 in several important particulars. 



Rcestelia penicillata, for example, a species incor- 

 rectly referred to R. lacerata, by certain authors, but very 

 properly retained as distinct by Winter (Pilze, p. 266), was 

 found, after an examination of several authentic European 

 specimens, to be a well-marked form quite different from any 

 known American species. R. penicillata. therefore, must be 

 definitely excluded from the list ot American forms unless it 

 has been wholly overlooked ; a supposition which seems 



