Nov., 1921] 
MAINS RUSTS ON NYSSA AND URTICASTRUM 
443 
Nyssa aquatica L., Jackson, Miss., Oct. or Nov. 12, 1888, II & III, S. M. 
Tracy 1200 (type)^; Ocean Springs, Miss., Nov. 4, 1891, II, F. S. Earle; 
Ocean Springs, Miss., Nov. 8, 1891, II, F. S. Earle; Great Cypress 
Swamp, Calvert City, Kentucky, II, W. W. Eggleston; obtained from 
a phanerogamic specimen, no. 5374, in the herbarium of the New York 
Botanical Garden by H. S. Jackson. 
The uredinia of this rust do not differ markedly from those of a number 
of genera belonging to the Melampsoraceae. The incurved paraphyses 
bordering the uredinium and united below into a short pseudoperidium are 
characteristics which are found in some species of Phakopsora (figs. 1,2). 
The urediniospores are borne in a very similar manner to that described 
by Butler^ for Cerotelium Fici (Cast.) Arth. {Kuehneola Fici Butler), the 
Fig. I (Left) . Paraphyses of Aplopsora Nyssae showing short pseudoperidium at their bases. 
Fig. 2 (Right). Portion of uredinium of Aplopsora Nyssae showing peripheral position of 
paraphyses and manner in which urediniospores are borne. 
hymenium consisting of a mass of cubical cells upon the uppermost of 
which the spores are borne (fig. 2). The cells bearing the spores have little 
to distinguish them from the other cells of the hymenium except that they 
are separated somewhat from each other. Whether these cells are to be 
considered as pedicels or whether, as Butler suggests for C. Fici, they in 
turn may develop into spores, cannot be determined from the material at 
hand, but there is no evidence that the spores form chains. 
The telia on the other hand characterize this rust as generically distinct. 
The teliospores arranged in a one-layered crust of cylindric, one-celled 
teliospores would place this species in a group with Melampsora, Melamp- 
soridium, and Chnoopsora (fig. 3). From the first two it is distinct tno 
only in uredinial characters but in that the telium soon ruptures the epider- 
mis and the teliospores germinate at once. In these characters it is much 
like species of Chnoopsora but differs in the method of teliospore formation. 
In species of Chnoopsora the teliospores are produced over a period of 
time due to young sporogenous hyphae developing between the older ones 
4 The description of Ellis gives the host as N. capitata and the date as Nov. 1888. 
Small, in his Flora of the Southeastern United States, gives the range of N. capitata as 
South Carolina to Georgia and Florida. Since other collections of this rust are on N. 
aquatica, it is likely that this collection is also on that host. There is also some confusion 
as to the date of the collection, some packets being labeled 10/12/1888 and some 11/12/1888. 
^Butler, E. J. Notes on some rusts in India. Ann. Mycol. 12: 76-82. 1914. 
