160 



Mycologia 



localities known to the writer for the Aecidium and Gymno- 

 sporangium are given : 



A. gracilens Peck : on Philadelphus microphyllus, " Colo- 

 rado," 1879, Brandegee {type) ; on Philadelphus sp., El Capitan 

 Mts., Lincoln Co., New Mex., July, 1906, Earle; on Philadelphus 

 occidentalis, Glenwood Springs, Colo., Aug., 1906, Osterhout. 



Gymnosporangium speciosum Peck: on Juniperus sp., " Colo- 

 rado," Brandegee, (type) ; on Juniperus utahensis, Mancos, Colo., 

 June, 1897, Bethel; Glenwood Springs, Colo., May 1, 1907, 

 Arthur & Kern; June, 1907, Bethel; Paonia, Colorado, August, 

 1909, Bethel; on Juniperus monosperma, Canon City, Colo., 

 Walsenburg, Colo., Trinidad, Colo., — all in June, 1909, Bethel. 



The relationship of A. gracilens to G. speciosum is merely 

 inferential and is based on field observations, distribution, and 

 the apparent roestelial characters of the Aecidium. Further, 

 the fact that sowings of G. speciosum have been tried unsuccess- 

 fully on Amelanchier, Crataegus, and Sorbus supports the infer- 

 ence that it may have its roestelial stage outside of the Malaceae. 

 This would be a very interesting connection, if established, since 

 the only known case of a Roestelia outside of the ligneous Mal- 

 aceae is that of G. exterum Arth., which occurs on Gillenia stipu- 

 lacea, an herbaceous annual of the Rosaceae, while Philadelphus 

 belongs to the Hydrangiaceae. G. speciosum occurs in woody 

 tissue of old branches, emerging through the bark in long longi- 

 tudinal, sinuous masses of a reddish or orange color, which ulti- 

 mately fade to a white color. It causes large hypertrophies, 

 sometimes six to ten inches in diameter, superficially resembling 

 those of Peridermium Harknessii Moore, on species of pine. 

 Denver, Colorado. 



