Hedgcock, Hunt, Hahn: Coleosporium 183 



All type specimens for the species described in this paper are 

 deposited in the Pathological Collections of the United States De- 

 partment of Agriculture, Washington, D. C. The numbers given 

 with collections apply to collections' for study in the Office of In- 

 vestigations in Forest Pathology, Washington, D. C. 



Coleosporium apocynaceum 



On March 27, 1918, near Silver Springs, Florida, a beautiful 

 Peridermium with delicate fimbriate peridia was collected from 

 the needles of Pinus caribaea, 3 P. palustris, and P. taeda, in direct 

 association with plants of Amsonia ciliata* bearing the uredinia of 

 Coleosporium apocyraceum Cooke, which were evidently from a 

 recent infection. Inoculations were made April 3, 1918, by Hunt 

 on six plants of Amsonia ciliata at Washington, D. C, in a green- 

 house, with the aeciospores of the Peridermium from Pinus taeda. 

 On April 15, the uredinia of Coleosporium apocynaceum Cooke 

 appeared on the leaves of one plant, and later the telia, establish- 

 ing that this Peridermium is the aecial stage of Coleosporium 

 apocynaceum (10). Hedgcock repeated this inoculation on plants 

 of Amsonia ciliata May 27, 191 8, with aeciospores from a collec- 

 tion of the Peridermium from Pinus palustris at Silver Springs. 

 May 7, 1918. Uredinia appeared on two plants June 9, and a 

 month later telia were formed. Control plants in both these ex- 

 periments remained free from the rust. Inoculations made with 

 urediniospores on plants of Amsonia ciliata April 24 and May 24, 

 1918, resulted in the production of uredinia May 8 and June 9, 

 respectively and of telia about a month later. 



The aecial stage of Coleosporium apocynaceum, for convenience 

 in distinguishing it from other species of the form genus Peri- 

 dermium, is here named Peridermium apocynaceum (Cooke) 

 Hedge. & Hunt, comb, nov., with the following description : 



Pycnia, amphigenous, scattered, in one row on each side of the 

 leaf, conspicuous, on chlorotic spots, dehiscent by a longitudinal 

 slit, hazel-brown to chestnut-brown, 0.4-0.8 mm. wide, 0.6-1.4 



3 The name of forest trees used in this paper are those recognized by Geo. 

 B. Sudworth in various publications of the Forest Service, Washington, D. C. 



4 The names of herbaceous plants and of shrubs are those recognized by 

 J. K. Small, Flora Southeastern United States, 1913. 



