18 
IOWA ACADEMY OF SCIENCE 
Rosa sp. 
Rudbeckia laciniata L. 
Solidago canadensis L. 
Verbena urticifolia L. 
In some cases, e. g. on the species of Lactuca, every specimen 
collected and examined proved to be infested by the Ampelomyces 
while in other instances, e. g. Verbena urticifolia only an occasional 
specimen was found. 
Often conidia bearing mycelium is found on a host and no peri- 
thecia are formed. In Decatur County I have found conidia on the 
following hosts not reported under any species in this work. In 
the absence of perithecia it is impossible to definitely determine 
the species to which they belong: 
Asclepias tuber osa L. 
Aster multiflorus Ait. 
Brassica sp. (Turnip.) 
Cucumis sativa L. 
Diospyros virginianum L. 
Geum virginicum L. 
Lactuca canadensis L. 
Lactuca floridana (L.) Gaertn. 
Lactuca sagittifolia Ell. 
Monarda fistulosa L. 
Physalis heterophylla Nus. 
Potentilla monspeliensis L. 
Rudbeckia laciniata L. 
Rudbeckia triloba L. 
Solanum carolinese L. 
Solidago ulmi folia. 
Xanthium canadense Mill. 
To these should be added the following reported by Prof. Fink 
at Fayette in 1893 : 
Chrysanthemum sp. (Curt.) 
Grindelia squarrosa (Pursh) Dunal. 
Mesadenia tuberosa (Nutt.) Britt. 
Phlox sp. 
Physostegia virginiana (L.) Benth. 
Roupa sylvestris (L.) Bess. 
Sisymbrium officinale Scop. 
On the same host plant perithecia may be formed one season but 
not another. During 1904 I looked for perithecia on Verbena 
hastata and V. urticifolia but found none although nearly every 
plant of the hosts were more or less affected with the conidial 
