16 
Journal of Mycology 
[Vol. 10 
L. and caesia L., clearly in accordance with the vigor of the 
host plants, while a sowing on >S\ rigida L. wholly failed, the 
host showing a weak growth. 
The above sowings were all made from material on Carex 
varia . The collection on C. lanuginosa, taken at the same time 
and place, appearing in every way to be the same species, and 
to be in equally viable condition, was sown under equally favor¬ 
able circumtsances on Silphium perfoliatum, Ribes Cynosbati, 
five species of Aster, and on Solidago rigida, S. serotina and re¬ 
peatedly on S. Canadensis, all with no infection. 
Whether the failure to infect the Solidago was due to some 
undetected oversight in manipulation, or is an indication of spe¬ 
cific or racial difference in the rust, is a matter for which the 
facts do not warrant an opinion. 
It is not easy to determine if this rust has been previously 
described and named or not. Upon morphological grounds it 
is clearly distinct from Uromyces caricina E. & E. and U. minu- 
tus Diet., but it may be the same as U. perigynius Halst. It also 
agrees well with collections from Wisconsin 13 on Carex gracillima 
Schw., from Decorah, Iowa, 14 on C. pubescens Muhl., and from 
Greencastle, Ind., 16 on what was taken to be C. pubescens , but 
which a re-examination shows to be almost certainly C. virescens 
Muhl. If the rust on C. varia and C. lanuginosa had shown the 
same cultural behavior, I would have been inclined to unite these 
several collections under one name. But realizing the need of 
advancing cautiously among a group of species where only the 
first step has been taken, it seems wiser to give a separate name 
to the form about which we have definite knowledge, and leave 
the others to be dealt with later. The rust on C. varia with its 
alternate form is therefore, characterized under a new name, as 
follows: 
Uromyces Solidagini-Caricis nom. nov. 
O. Spermogonia epiphyllous, in small groups on yellow spots, punc- 
tiform, honey yellow, subepidermal, in vertical section shown to be 
globose, about 115 /x in diameter; isticlar filaments free, 60 [x long: 
I. Aecidia hypophyllous, in groups, often circinating, peridia pale, 
low cylindrical, margin revolute, lacerate; aecidiospores globoid, or 
slightly elongated, 13-16 by 14-18 /*; wall colorless, thin, 1 /t or some¬ 
times a little more, minutely rugose. 
II. Uredosori not seen; uredospores among the teleutospores oval 
or obovate, about 16 by 23 n ; wall thin, echinulate. 
III. Teleutosori hypophyllous, round, oblong or sometimes elong¬ 
ated, pulvinate, early naked, firm, chestnut-brown; teleutospores obovate, 
15-18 by 23-28 /a, rounded or obtuse above, narrowed below; wall smooth, 
thin, 1.5-2/*, apex greatly thickened, 6-10/-*; pedicel slender, tinted, as 
long as the spore, or longer. 
13 Trans. Wis. Acad. Sci. p:180. 1892. Same 14 : 90. 1903. 
14 Bot. Gaz. 1(5:226. 1891. 
16 Same, 1. c. 
