528 
involute leaves, absence of peristome and the neck shorter than 
the sporange. 
ROSEMONT, N. J. 
Microsphaera densissima (Schwein.) Peck. 
By Gero. F. ATKINSON, 
This very interesting species first described by Schweinitz* 
as Erysiphe densissima, was collected by mé at Ithaca, N. Y., 
August 7, 1893. There has been some uncertainty as to the 
identity of this species of Schweinitz, and probably for this. “ 
reason Burrill omits a description of it in his latest work on the 5% 
Erysipheae.+ It is only mentioned in a discussion of its once — : : 
supposed identity with a very different fungus, Mtcrosphaera cal- | 
ocladophora,t Atkinson. In his article on the Erysipheae§ of 
Illinois, Burrill refers to it as follows: “ Microsphaera densissima 
(Schw.) Peck, cannot be distinguished by its perithecia from the 
ordinary form on Q. rubra, but it presents some peculiarities of 
the mycelium, which if constant would entitle it to specific dis- 
tinctness.” The specimens agree perfectly, it seems to me, with - 
Schweinitz’ description, the patches of whitish mycelium being 
very dense with a long filamentous tomentum. The patches ale 
beautifully orbicular, the prostrate threads lying close to the leaf 
and beautifully radiate from the center. The portions of the leaf 
on which the mycelium is seated are very much injured, so tha 
they become yellowish and marked with numerous black spo! 
on the lower side. It occurs at Ithaca on Quercus tinctoria. Ac 
cording to Burrill, Peck reports it on Q. dinctoria. In the 26th 
Report of the New York State Museum, p. 80, Peck reports it OF 
_ fallen leaves. Several years ago while studying the species| 
which occurs on Q. aguatica and O. laurifolia in the Southern Stat 
* Syn. Am, Bor. n. 2479.- td hae 
+ Ellis’ North Am. Pyren. 29. a ae 
_ $Some Erysipheae from Carolina and Alabama. Jour. Elisha Mit oe 
Ags 13 } ones a 
- $ Bull. Ill. State Lab. Nat. Hist. 2: 426. 1887. ie 
| Microsphaera calocladophora Atkinson, See note }- pee 
