1048 
Journal of Agricultural Research 
Vol. XXVIII, No. 10 
Dr. N. E. Stevens, while en route by automobile from Washington, D. C., to 
Providence, R. I., June 4 to 6, sent in 35 specimens of orange-rust on blackberries 
and dewberries. The germination tests show that the strain which develops 
spermogonia and 4-celled promycelia was more abundant along this route at that 
time than was the strain without spermogonia and producing 2-celled promy¬ 
celia; only 7 specimens were of the latter type, while 23 were of the type which 
develops 4-celled promycelia. 
Whether the strain which develops 2-spored promycelia may not be relatively 
more abundant as one goes farther South can not be said with certainty. When 
the result of germination tests of rust collected from northern New Jersey and 
central New York are compared with those from North Carolina and Georgia, 
it might seem that the strain without spermogonia which develops 2-celled 
promycelia is more abundant in the South. All of the specimens collected at 
Junius, Geneva, and Albany, N. Y., June 16 to 18, showed at least some sper¬ 
mogonia. Only a few localities were visited but it is possible that the strain in 
which the spermogonial structures are poorly developed or omitted is not so 
common in the North. Of the 24 specimens tested 5 were long-cycled. Two- 
celled promycelia developed from spores from 2 specimens. 
Several other collections were made at Ridgewood, N. J. Owing to the exces¬ 
sively hot weather prevailing and the delay in the mails, very poor germination 
was obtained. All of these specimens collected June 19 on wild dewberry showed 
spermogonia when carefully examined later. When germination was such as to 
enable one to determine the nature of the promycelium, it was found to be 4-celled. 
A few long germ tubes were seen in cultures from 6 specimens on blackberry. 
Very likely this rust was long-cycled and further search later will result in the 
discovery of telia in this vicinity. 
All of the leaves in specimens collected at Wells Beach, Me., June 22, on wild 
dewberry and blackberry, were covered with spermogonia. Tests proved that 
the rust here is long-cycled. Dr. D. Folsom has sent in specimens of orange- 
rust collected in Maine. Germination was tested at Orono and the rust found 
to be short-cycled. 
A number of plants of different varieties and species of Rubus infected with 
orange-rust are grown in the greenhouse at Arlington, Va., from year to year. 
In every case here so far tested, where spermogonia are readily seen with a hand 
lens, the rust is either long-cycled, or if short-cycled, it develops 4-celled promy¬ 
celia. 
With the results of-all the germination tests reported above in mind, it is pos¬ 
sible to make three general statements covering this phase of the question. 
(1) Spermogonia are always found in considerable numbers on leaves of Rubus 
infected with the long-cycled orange-rust Gymnoconia interstitialis. 
(2) If no spermogonia are present on a leaf showing aecidia of orange-rust 
the spores will be found to be uninucleated, and on germination they will form 
2-celled promycelia. 
(3) In strains of the short-cycled rust whose spores develop 4-celled promy¬ 
celia, spermogonia always precede or accompany the formation of aecidia. 
TWO-CELLED PROMYCELIA FROM A STRAIN HAVING SPER¬ 
MOGONIA 
During the prosecution of this survey work there has been found very rarely a 
form of orange-rust in which spermogonia appear to be fairly well developed, 
yet the aecidiospores are uninucleated and develop 2-celled promycelia. A 
Crandall blackberry was found infected with this type. Some of the Eldorado 
blackberries in Doctor Rankin's experimental plots at Geneva, N. Y., show 
