Dec. 1903 ] Uredineous Infection Experiments in ipoj 
233 
being Hibiscus moscheutos L., H. militaris Cav., and Althaea 
rosea (Cav.) 
Furthermore, Rev. J. M. Bates kindly furnished me from 
Nebraska, an ample quantity of Muhlenbergia racemosa (Mx.) 
B.S.P. that harbored the Rust, and the latter was used in an 
attempted inoculation of Hibiscus moscheutos L., H. militaris 
Cav., and Napsea dioica L. In no case was an infection secured. 
It is not clear how the failures in the above cases should be 
explained. The apparent conditions were all favorable — 
though of course no one can pronounce conclusively thereupon. 
A suggestion may possibly be apropos, namely, that we have here 
to do with physiological forms restricted to different hosts. The 
hypothesis signifies nothing however until positive results may be 
obtained with material from the hosts named. A careful ex¬ 
amination by the aid of student J. N. Frank, revealed to us no 
morphological differences between the spores found on the three 
species of Muhlenbergia. However the sori on Muhlenbergia 
mexieana were more numerous — the plants in fact quite black¬ 
ened with the rust and easily noticed in their natural habitat, at 
a distance of three or four rods. 
Finally it is to be noted that successful inoculations (Exp. 
165) were made with teleutospores from Muhlenbergia mexi- 
cana on Hibiscus militaris Cav. Attempted infection of several 
other species of plants of the same and of different orders was 
not successful. The complete record follows. 
Exp. 146. 
Exp. 147. 
Exp. 148. 
Exp. 149. 
Exp. 150. 
Exp. 161. 
Exp. 162. 
Exp. 163. 
Exp. 165. 
Exp. 222. 
Exp. 223. 
Exp. 228. 
Exp. 182. 
Exp. 183. 
Exp. 184. 
Exp. 166. 
Exp. 167. 
Exp. 168. 
Exp. 169. 
April 24. Teleutospores from Muhlenbergia mexieana (L.) 
Trin. applied to Hibiscus moscheutos L. Sperniogonici May 5 , 
(abundant May 8 ); aecidia May 15 . 
April 24. Same to Rudbeckia speciosa Wenderoth. No in¬ 
fection. 
April 24. Same to Urtica gracilis Ait. No infection. 
April 24. Same to Ambrosia trifida L. No infection. 
April 24. Same to Erigeron annuus (L.) Pers. No infection. 
May 5. Same to Hibiscus moscheutos L. Spermogonia 
abundant May 13 , and aecidia later. 
May 23. Same to Althaea rosea Cav. No infection. 
May 23. Same to Malva rotundifolia L. No infection. 
May 23. Same to Hibiscus militaris Cav. Spermogonia June 
3 , aecidia very abundant (date lost). 
June 7. Same to Hibiscus moscheutos L. Aecidia June 16 . 
June 7. Same to Althaea rosea Cav. No infection. 
June 8. Same to Abutilon abutilon (L.) Rusby. No infection. 
May 28. Teleutospores from Muhlenbergia diffusa Willd. 
applied to Hibiscus moscheutos L. No infection. 
May 28. Same to Althaea rosea Cav. No infection. 
May 28. Same to Hibiscus militaris Cav. No infection. 
(Apparently one spermogenial spot — but doubtless to be re¬ 
ferred to accidental infection from another experiment.) 
May 24. Teleutospores from Muhlenbergia racemosa (Mx.) 
B. S. P. applied to Hibiscus moscheutos L. No infection. 
May 24. Same to Althaea rosea Cav. No infection. 
May 24. Same to Napaea dioica L. No infection. 
May 24. Same to Hibiscus militaris Cav. No infection. 
