96 U.S. DEPT. OF AGRICULTURE MISC. PUB. 939 



the aeciospores usually coincides with the bud break of the oak. Ure- 

 dia appear on the oak leaves 1 to 2 weeks after infection by aecio- 

 spores. Urediospores may repeat infections on oak until leaves be- 

 come immune, 2 to 3 weeks after they are fully expanded. Telia ap- 

 pear in early summer and produce basidiospores which infect the 

 young growth of the pine from early to midsummer. 



Range : North America. Common from Maine, Ontario, and Minne- 

 sota to Florida and Texas. 

 Hosts: 



Pinaceae (0) (I) — 



Pinus banksiana Lamb. 



P. clausa (Engelm.) Vasey 



P. echinata Mill. 



P. elliottii Engelm. 



P. glabra Walt. 



P. nigra Arnold (Planted in U.S.) 



P. ponderosa Laws. 



P. pungens Lamb. 



P. resinosa Ait. 



P. rigida Mill. 



P. sylvestris L. (Planted in U.S.) 



P. iaeda L. 



P. thwtibergii Pari. (Planted in U.S.) 



P. virginiana Mill. 

 Fagaceae (II) (III) — 



Castanea dentata (Marsh.) Borkh. 



C.pumila (L.) Mill. 



Quercus alba L. 



Q. bicolor Willd. 



Q. coccinea Muench. 



Q. ilicifolia Wangenh. 



Q. imbricaria Michx. 



Q. macrocarpa Michx. 



Q. marilandica Muench. 



Q. myrtifolia Willd. 



Q. nigra Ij. 



Q. pahistris Muench. 



Q.phelloslu. 



Q. primes L. 



Q. rubral^. 



Q. stellata Wangenh. 



Q.velutina~L&m. 



Q. virginiana var. minima (Small) Sarg. 

 Literature : 



Cummins, G. B., and Stevenson, J. A. A check list of North Ameri- 

 can rust fungi (Uredinales) . Plant Dis. Rptr. Sup. 240 : 109-193. 



1956. 

 Dodge, B. O., and Adams, J. F. Some observations on the develop- 

 ment of Peridermium cerebrum. Torrey Bot. Club Mem. 17: 



253-261. 1918. 

 Hedgcock, G. G., and Siggers, P. V. A comparison of the pine-oak 



rusts. U.S. Dept. Agr. Tech. Bui. 978 :l-30. 1949. 





