480 IOWA ACADEMY OF SCIENCE 



Hyalosora aspidiotis (Peek) Magn. 



II. Ill — On Phegopteris dryopteris (L.) Fee. (67). 

 This is quite common. 

 Peridermium coloradense (Diet.) Artli. 

 I— On Picea sitchensis (Bong'.) T. & M. (57). 



This is very common around open places, hut does not 

 seem to be found in the denser forest. It is sometimes 

 quite destructive to small trees, as it causes a loss of a 

 large portion of the leaves. It is included under the 

 family Melampsoracece as probably it is genetically con- 

 nected with one of the foregoing species. 



PUCCINIACE^E. 



Phragmidium occidentale Arth. 



On Bubus parviflorus Nutt. (50 and 51). 



On the Station grounds this rust is abundant enough to be 

 decidedly injurious to the host. 

 Phragmidium, rosae-acicularis Liro. 



On Rosa hemisphaerica Herrm. (19). This host seems some- 

 what more susceptible than B. rugosa and its hybrids. 



On Bosa n utkana Presl. (52 and 53) . This is our native rose. 

 It seems very susceptible. 



On Bosa rugosa (267) and hybrids (195). 

 Xenodochus minor Arth. 



On Sanguisorba latifolia (Hook.) Coville. (54, 113 and 202) 

 This rust is very common. All the forms occur. Dr. Arthur, 

 in a letter to the writer, says concerning some material be- 

 longing to this species, which was sent to him September, 

 1915, "Your material gives the first collection of a?cia be- 

 longing to Xenodochus minor, which has come to hand." 

 Gymnosporangium sorbi (Arth.) Kern. 



0, I — On Pyrus {Mains) diversifolia Bong. (56). 



This rust is common on the native crab apple and is some- 

 times injurious locally. 



0, I— On Sorbus sitchensis Roem. (55). During 1914, this 

 species was badly affected, but in 1915 it had suffered to 

 such an extent from attacks of Entomosporium that but 

 few leaves were left to be attacked by the rust. 



