THE AECIAL STAGE OF ALSIKE CLOVER RUST. 
W. H. DAVIS. 
A rust belonging to the genus Uromyces is rather prevalent 
in this latitude on the common clovers, white (. Trifolium repens 
L.), red ( Tri folium pratense L.) and alsike ( Trifolium hybri- 
dum L.). The rusts on clovers were formerly classified as a 
single species or one rust until the work of Liro separated them 
into two species, one on red and one on white clover. The dis- 
position of the rust on alsike clover is not clear. Liro (9), in 
his inoculations 93-94, tried to inoculate alsike with uredinio- 
spores of white clover rust, but the results were negative. Ac- 
cording to Sydow (6, p. 133) Alsike clover is a host for the 
rust on red clover ( T . pratense ) while Arthur (2, p. 225) gives 
Alsike as a host for the same rust as found on white clover. 
There seems to be a general belief that the rust of white and of 
alsike clover are of the same species. This belief is confirmed 
by the fact that they are morphologically similar in two respects ; 
the sizes of the urediniospores and telispores are similar and the 
urediniospores of each have two to three germspores equatorially 
placed. They differ in the number of known spore forms — • 
white clover has all five spore forms, while alsike has no pycnia 
and aecia. Rostrup (6, p. 134) reported aecia on alsike in Ger- 
manjr (1886) but the correct determination of the host is cnies- 
tioned. It is not generally accepted that alsike rust has a pyc- 
nian and an aecial stage. 
On April 25, 1916, several out of door clover plats were under 
careful observation for the aecial stage of rusts when golden 
swellings were noticed on the midribs of the leaves on an alsike 
clover plant. The Alsike plants had been left uncut during the 
summer and fall of 1915, so the old rusted leaves and stems 
remained intact. 
On April 27, 1916, specimens of aecia were picked and used 
for inoculating purposes. As aecia and pycnia were abundant 
during the month of May, material was killed, imbedded for 
sectioning and pressed for herbarium specimens. The aecial 
stage continued to develop until June 7 when none could be lo- 
cated. The aecial stage of this rust could not be located around 
