240. BULLETIN OF THE BUSSEY INSTITUTION. 
dium. P. mucronatum, Pers., is very common on both wild and 
cultivated roses; and the same species, sometimes known under the 
name of P. incrassatum, Lk., is found on both wild and cultivated 
species of Rubus, on which it forms more dense black patches than 
when growing ‘on roses. Equally common is P. Potentille, Pers. 
(P. obtusum, K. & §S.) which is abundant on Potentilla Canadensis, 
where it is usually found mixed with Spheria Potentille, Schw. The 
species is generally known as Aregma triarticulatum, B. & C.; but 
we agree with Schreeter in thinking that the species is not distinct 
from P. Potentille, Pers. When young, the spores appear sometimes 
club-shaped, but when ripe they are as regularly elliptic as are the 
spores of P. Potentille. We cannot, however, agree with Schreeter,* 
in thinking that P. speciosum, Fr., is not distinct. Apart from the 
extraordinary habit, which to the eye resembles much more that of a 
Dothidea than a Phragmidium, the spores are distinguished by being 
almost entirely smooth, tipped with a minute point, and attached to 
very long pedicels. The number of divisions of the spores is about 
6-8. Schroeter is in error in supposing that this striking species 
was unknown to Schweinitz. It is mentioned in the “Synopsis Fung. 
Am. Bor.,” p. 306, No. 8084, and referred to Secridium marginatum, 
Lk. Schweinitz remarks that the species exactly agrees with the 
figure of Nees,f which extraordinary statement is explained by the 
reference to the “lentem quam minime augentem.” Streinz+ has 
increased the confusion by giving Seiridium marginatum, Nees, as a 
synonym of Aregma (Phragmidium) speciosum, Fr., whereas Fries § 
distinctly states that his species is the Seiridium marginatum of 
Schweinitz and not-of Nees, and gives as a locality only North Amer- 
ica, while Streinz mentions as well Central Europe. Schweinitz, in 
the work above mentioned, describes a second species, Secridium Smi- 
lacis, which he says is common on species of Smilax at Bethlehem. 
We have examined an original specimen of the so-called S. Smilacis, 
and find that it is identical with Phragmidium speciosum. Further- 
more, the supposed twig of Smilax is exogenous and not endogenous, 
and evidently belongs to some Rosaceous shrub. Of course, it is 
* “Hedwigia,” Vol. XIV. p. 166. 
t “Syst. der Pilze und Schwimme,” PI. I. fig. 19. 
t “ Nomenclator Fungorum,” p. 181. 
§ “Syst. Mycolog.” III. p. 496. 
