8 BULLETIN 871, IT. S. DEPARTMENT OF AGRICULTURE. 
the decays were so badly eaten out by insects as to preclude any 
description of the rot. By reason of this, some light infections of 
Polyporus amarus may have been included under secondary rots, 
but such cases have undoubtedly been very rare. 
Of the 59 infections of secondary rots examined, only 9 resulted 
in culls of any importance, the highest percentage of unmerchant- 
able timber in relation to the total volume of the tree being 19.5 
per cent. In all the remaining 50 trees the infections were negligible. 
These figures show secondary rots to be of only trivial importance in 
reducing the merchantable volume: hence, such decays are not 
further considered in this paper. 
THE DRY-ROT. 
The dry-rot of incense cedar, termed by eastern workers "pecki- 
ness" or "pin-rot," caused by the fungus Polyporus amarus Hedge, 
was first described and figured by Harkness (7) but no cause was 
given. Next Von Schrenk (26, 67-77, pi. 2, 4, 5) described and 
figured the disease without stating the cause, and later (28) he 
mentions Polyporus libocedris, but without giving a description of 
type specimens. Hedgcock (10) first definitely assigned the cause 
of the dry-rot to Polyporus amarus sp. no v. and described the fungus. 
Later Meinecke (15, p. 35-37) presented a brief description of the 
sporophore, accompanied by a photograph of a typical fully devel- 
oped bell-shaped specimen, with the upper surface partially destroyed 
by insects. Murrill (24, p. 25) places the fungus in the genus Fomes. 
Harkness and Moore, Mayr, and Sargent have attributed the cause 
of the dry-rot to Daedalea vorax Hke., but Yon Schrenk (26, p. 67-68) 
has shown this to be an error. Farlow and Seymour (5, p. 169) and 
Bryant (1, p. 15) have made the same mistake. 
The dry-rot is very widely distributed. It has been found at 
elevations varying from 650 to 6,480 feet as far north as Oakridge, 
Lane County, Oreg., west to the west of China Flat, Humboldt 
County, Calif., east to Shaver, Fresno County, Calif., and south to 
the north and east of Mentone, San Bernardino County, Calif. In 
fact, from all indications and hearsay evidence it is quite reasonable 
to presume that dry-rot is more or less prevalent in incense cedar 
throughout the range of the host (30, p. 150-152). 
THE SPOROPHORE. 
Since Hedgcock's description was published, so many sporophores 
have been collected that the original description may be supplemented 
by the following, which is based on the examination of 25 sporophores, 
both fresh and old : 
Polyporus amarus. — Pileus soft and mushy when young, then rather tough and 
cheesy, finally becoming hard and chalky when old, ungulate, bell shaped or occa- 
