4 . BULLETIN 1053, U. S. DEPARTMENT OF AGRICULTURE. 



Lenzites sepiaria has been studied as a destroyer of coniferous tim- 

 bers in buildings by Falck (15) in Europe and out of doors by Spauld- 

 ing (58) in this country. Its importance in the destruction of mill 

 roofs was suspected by Hoxie (24) in 1915, and since then he and 

 others, including the writer, have found it fruiting quite commonly 

 and doing much damage in such places. (PI. I, figs. 1 and 2.) Len- 

 zites trabea has been reported by Blair (1) as destroying weave-shed 

 roofs. This species, though usually found upon hardwoods in nature, 

 probably occurs more commonly and is more destructive to coniferous 

 lumber under mill conditions than has yet been reported. The writer 

 has found it fruiting upon yellow pine and spruce roofs. (PI. I, 

 figs. 3 and 4.) 



Trametes serialis has been found upon some of the more badly de- 

 cayed roofs along with other fungi (PI. I, fig. 5 ; PI. II, figs. 1 and 2) , 

 but within buildings it is usually upon basement timbers. This fungus 

 generally occurs in the resupinate form and also forms abortive struc- 

 tures. 



Forties roseus is found within mills upon beams in moist basements 

 (PL II, fig. 5) . The annual form is the one of common occurrence, and 

 whether or not the perennial form also occurs is not certain. Many 

 mycologists consider the annual form as a distinct species, Trametes 

 earnea. 



Lentinus lepideus has been found upon roof timbers under very 

 moist conditions and in basements (PI. II, figs. 3 and 4). It also 

 occurs in Europe on building timbers (cf. Mez, 35; Falck, 17.) Its 

 destructiveness to structural timber in the open is well known. 



BASIDIOSPORES. 



SOURCES OF BASIDIOSPORE MATERIAL. 



The basidiospores used were obtained for the most part from fruit 

 bodies collected in the field. Those of Lenzites sepiaria were from 

 various collections in Wisconsin. The spores of Lenzites trabea were 

 obtained from fruit bodies upon pulpwood bolts, collected in Penn- 

 sylvania, by F. J. Hoxie. The basidiospores of Trametes seri- 

 alis were obtained from fructifications on some rotten timbers (re- 

 moved on account of decay) from the pulp-and-paper section in the 

 Forest Products Laboratory and placed in the forest-pathology 

 greenhouse. From two or three small sporophores formed in No- 

 vember, 1919, sufficiently large numbers of spores were obtained to 

 last through two winters of experimentation. Sporophores of the 

 annual form of Fomes roseus were collected upon tamarack (Lariat 

 Jaricina) logs in Wisconsin and red spruce (Picea rubens) in New 

 Hampshire. The spores of L.entinus lepideus were obtained from 

 sporophores collected by Mr. Hoxie in a cotton mill in Massachusetts. 



