32 
BULLETIN 510, U. S. DEPARTMENT OF AGRICULTURE. 
out, shiny above, rather thin and shelflike, which is found abun- 
dantly throughout the South on hardwood timbers; and P. gilvus 
Schw. (PL VI, figs. 2 and 3), a firm, comparatively thin, rather 
rigid species, yellowish within and reddish brown without as it ages. 
In the northeastern United States one occasionally finds on oak 
or chestnut timbers the heavy, tough, corky fruit bodies of Daedalea 
quercina (L.) Pers. (PI. VI, fig. 1). Y\hen the plant develops nor- 
mally it forms large and sinuous pores, but in lumberyards it more 
often appears as abortive clay-colored cushions (PI. III. fig. -1). It 
is one of the few fungi which attack white oak and chestnut. 
Another destructive group of fungi is represented by the genus 
Lenzites. Among the brown species there are three principal ones to 
be feared: Lenzites 
sepiaria (TTulf.) Fr. 
(PI. VI, figs. 5 and 
6),Z. oerheleyi Sacc. 
(PL VI, fig. T), and 
Z. trabea (Pers.) Fr. 
(PI. VII, fig. 1). 
The first two con- 
stitute the most seri- 
ous enemies of conif- 
erous structural tim- 
ber in the United 
States. The last spe- 
cies rots both the 
heartwood and sap- 
wood of many differ- 
ent kinds of hard- 
woods. All three are 
brown throughout 
and leathery to 
corky in texture. In 
some fruit bodies the 
under surface may consist of distinct gills ; in others, the gills may 
more or less run together to form sinuous to subcircular pores, easily 
visible to the naked eye. 
Another species, Lenzites oetulina (L.) Fr. (PL VII, figs. 2 and 3), 
of a general creamy color, with an upper surface frequently banded 
with shades of yellow, orange, and brown, occurs on hardwood tim- 
ber throughout the United States. It has commonly been noted in 
lumberyards on timbers used in various structures. In one largo 
mill yard where oak was largely used for planking the elevated tram- 
ways, this species, in conjunction with Polystictus versicolor, suc- 
Fig. 33. — A very congested retail yard at New Orleans, La., 
showing lumber temporarily placed on the ground in solid 
piles. This is a bad practice, because under such condi- 
tions decay may start in a very short time. 
