296 



[Vol. 13 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



in underground portions of various plants and forming at their 

 surface underground minute sclerotia; fructification a thin, arach- 

 noid, perforate membrane more or less separable, pale olive-buff 

 to cream color; in structure 60-100 ;x thick, composed of a few 

 loosely interwoven hyphae running along the substratum and 

 sending out short branches which bear the basidia; hyphae in 

 contact with substratum may be slightly brownish, hyaline else- 

 where, not incrusted, not nodose-septate, up to 6-10 \l in di- 

 ameter, with branches smaller; basidia not forming a compact 

 hymenium, 10-20 X 7J/-ll ji, with 4-6 sterigmata 6-10 (x long 



Fig. 3. C. vagum, X 870. a-a, from specimen on potato in Colorado, a, 

 hypha; al, basidium; a2, spores. 6, spores of specimen on Plantago in Illinois. 

 c~cly from specimen on earth in Massachusetts, c, basidium: cl, spores. d-~d f 

 from specimen on wood in British Columbia, d, hypha; dl, basidia; dt> spores. 



and more or less swollen towards the basidium; spores hyaline, 

 even, flattened on one side, 8-14 X 4-6 \i. 



Fructifications 5-15 cm. long on logs, 5-10 cm. broad; in a 

 collar 1-10 cm. long, sheathing the base of living stems. 



On bare earth, wood and bark lying on the ground, and on living 

 stems of potatoes, beans, rhubarb, horseradish, tomatoes, Ama- 

 ranthus, etc., at or near the ground. New Brunswick to Florida 

 and westward to Vancouver and Washington, in West Indies, 

 Europe, India, and Australia. Common. 



Corticium vagum differs from C. koleroga and C. Stevensii in 

 having its mycelium and sclerotia subterranean when parasitic, 

 in having its fructifications at the surface of the ground or merely 

 sheathing small herbaceous stems for only a few centimeters up 

 from the ground and never spreading out on the under side of 



