NEW SPECIES AND RELATIONSHIPS IN THE 

 GENUS COLEOSPORIUM 



George G. Hedgcock, N. Rex Hunt, and Glenn G. Hahn 



A study of the species of the form genus Peridermium occur- 

 ring on the needles of pines in the United States, and of their 

 relation to the various species of Coleosporium in the same range 

 was begun by the senior writer in 1912. He has since been as- 

 sisted in this work as follows : by William H. Long in 1914, by 

 N. Rex Hunt from 191 5 to 1918, and by Glenn G. Hahn in 1919 

 and 1920. All collections cited in this paper without the name of 

 the collector were made by the senior writer ; where made by 

 others the name of the collector is given. This paper gives some 

 of the results of the more critical sets of inoculations made with 

 several species, chiefly during the past three years. 



In the descriptions of fungi given in this paper, all measure-* 

 ments for averages are based upon either 50 or 100, individual 

 measurements. Materials for study are prepared as follows : 

 dried specimens are first placed in water, then heated to the boiling 

 point, transferred to a 10 per cent, gum arabic solution for 15 

 minutes and sectioned with a freezing microtome. Sections are 

 mounted in a solution of 30 per cent, glycerine in water tinged 

 with erythrosin. Measurements of the sori of pycnia and aecia 

 in length and width are taken chiefly from unsectioned dry 

 material. Measurements of cell walls are the estimated median 

 for the side walls of each cell and include wall papillae. The 

 colors of pycnia, aeciospores, and peridia are based on fresh 

 material. 1 As has already been pointed out (7), 2 the color in 

 fresh pycnia furnishes a good diagnostic character. Pycnia when 

 old fade, and although this feature loses in value with age, other 

 characters still hold, such as arrangement on the leaves, and size. 



1 Colors used are those of R. Ridgway, Color Standards and Color Nomen- 

 clature, Washington, D. C, 1912. 



2 Numbers in parentheses refer to publications cited at the close of the 

 paper. 



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