238 BOTANICAL GAZETTE. [Sept., 
as J. Virginiana botanists may, perhaps, discover the species in 
regions where it is not now known. 
Taking next the form which grows on Juniperus Virginiana 
and produces the well known birds-nest distortions, sowings were 
made on Pyrus Americana, apple, Amelanchier, and Pyrus 
arbutifolia and spermogonia appeared in great abundance om 
Amelanchier in seven days and on one apple in eight days and 
in a month ecidia developed on Amelanchier. The species was 
R. cornuta which is considered in Europe to belong to Gymn. con- 
icum. Why the ecidia did not also develop on Pyrus Ameri- 
eana, the host on whic . cornuta occurs in its most marked 
form in this country, is a question. The failure in the present 
ease may be merely an accident and future cultures may succeed. 
At any rate, the experiments should be repeated several times 
before we conclude that the spores of the birds-nest form will not 
w on Pyrus Americana. Considering the distribution, the 
result of the cultures, and in general the anatomical structure, I 
think that it is most probable that the species is Gymn. conicum 
which Oersted concluded from his cultures to be connected with 
Cultures were also made of the spores of Gym. clavarieforme, 
a species which grows on J. communis, and has apparently beer 
more abundant this year than usual. Although sown on Pyrus 
Americana, apples, and Crategus they only grew on the Crategus 
where they produced Roestelia Jacerata, the xcidium which in 
Europe is believed to be connected with the same species. In 
general the distribution of the Gymnosporangium and the Roe- 
stelia is about the same in the north and west, although the latter 
is much more common and is found in places not very near juni- 
per trees. 
that the species is connected with Roestelia transformans which 
occurs on the Pyrus, 
