ORSERVATIONS ON PUCCINA MIRABILISSIMA. 133 
The specific connection between this A’cidiwm and the 
previously described Puccinia is by no means well estab- 
lished. I find no reason for distinguishing it from the 
Afcidium from Utah described by Tracy and Galloway and 
the association of the two forms from the two localities is the 
only evidence we have for assuming this relationship. I 
also have specimens of Berberis repens, collected by Holway 
in Colorado, bearing on the same leaves the uredo stage of 
Puccinia mirabilissima and an Afcidium that seems to be 
distinct from the one under consideration. It occurs in 
large groups on yellow unthickened spots and is larger 
and shorter than the one found at Berkeley. Its spores are 
more nearly subglobose and vary from 21, to 23 in diameter. 
In addition to these facts are those observed by Mr. T. D. 
Cockerel who finds in Colorado an A¥cidium that he believes 
to be identical with that of Tracy and Galloway but after 
careful search is unable to find even a trace of Peck’s 
Puccinia. 
Calture experiments alone can show the existence or non- 
existence of this relation and these have proved somewhat 
difficult to carry out. I made two attempts to produce 
ecidia by sowing the uredo and teleutospores on detached 
leaves under a bell jar but in both cases without results. I 
hope to be able to carry out more satisfactory cultures as 
soon as suitable young plants can be grown. 
_ A comparison of the fungus found at Berkeley with that of 
the Sierras gave almost identical results. The average of 
teleutospore measurements was 23.2x33.2 instead of 23x33 u 
and uredospores show a similar agreement, No Acidium on 
Berberis as far as I know has been reported from the Sierras. 
The germination of the uredo- and teleutospores was readily 
observed by the usual method of hanging-drop cultures for 
which distilled water was found to be the most satisfactory 
medium. 
Under such conditions the uredospores begin to germinate 
abundantly at the end of twelve hours; frequently two and 
sometimes three of the germ-pores giving rise to germ-tubes 
