Arthur: Cultures of Uredineae 
77 
Telia from 
North Dakota ... 
Colorado 
Montana 
North Dakota ... 
North Dakota ... 
Prediction 
for Aecia 
Carduus 
Ambrosia 
Ambrosia 
Ambrosia 
Eate of 
Sowing 
Host for Culture 
A ‘I 22! / Carduus Flodmanii 
j ( Ambrosia psiloslachya 
( Ambrosia psiloslachya 
April 23 -j Ambrosia trifida 
( Carduus Flodmanii 
f Ambrosia psilostaihya 
May 6 Ambrosia trifida 
( Carduus Flodmanii 
Ambrosia psiloslachya 
Ambrosia artemisiaefolia 
Ambrosia trifida 
May 1 1 Carduus Flodmanii 
Silphium perfoliatum 
Laciniaria scariosa 
Xanthium canadense 
Ambrosia psiloslachya 
May 1 1 Ambrosia trifida 
Xan/hium canadense 
First ! First 
Pycnia 1 Aecia 
May 7 May 12 
May 8 May 12 
May 8 
May 16 May 21 
May 22 May 27 
May 20! May 27 
May 271 
The three collections sent by Dr. Brenckle from Kiilm, N. Dak., 
bore out the prediction that he had based upon field observations. 
One of the collections grew upon both Ambrosia and Carduus, 
indicating that the races are not invariably fixed. The collection 
sent by Mr. Bethel from Boulder, Colo., also bore out the predic- 
tion which he had based on a field observation. No suggestions 
came with the collection sent by IVIr. Vasku from Nihill, Mont. 
As stated in the North American Flora (7: 238. 1912), only 
Carduus has heretofore been proven by cultures in this country to 
be a host to this species, although both Ambrosia and Arnica have 
been considered to be hosts, a conclusion derived from morpholog- 
ical and field studies.^® 
10. Uromyces acumin.atus Arth. — A collection made by Mr. 
Bethel at Boulder, Colo., on Spartina Michauxiana, showing the 
characteristic slender, acuminate teliospores to which this name 
has been applied, was suspected from field observations to belong 
to aecia found on CoUomia. Sowings were made April 29 on 
Collomia linearis, Stcironcma ciliatum and S. lanccolatum. In- 
fection resulted only on CoUomia, showing a great abundance of 
pycnia May 8, and aecia May 12. 
This culture adds one more host experimentally proven to be- 
long to this species, although it had been associated with the spe- 
29 For previous cultures see Jour. Myc. 14: 12. 1908; Mycol. 2: 
1910 ; 4 ; 22. 1912. 
220. 
