70 MISSOURI BOTANICAL GARDEN, 
been applied to a form of decay in the cypress in which the 
wood is destroyed in local pockets. As this is a distinct 
form of wood destruction I would apply the term « pecky”’ 
to all forms of destruction where pockets or holes are 
formed as in the cypress. One would therefore call the 
affected Libocedrus wood ‘+ pecky cedar.”’ 
STRUCTURE OF DiskasED Woop. 
The normal wood of Libocedrus differs but little from that 
of Taxodium distichum. Penhallow * places the two genera 
side by side. The diseased wood is decidedly different 
from the healthy wood. It has the appearance of 2 brown 
charcoal, breaks with a dull fracture and when pressed 
crumbles into a fine powder. In the mortar an impalpable 
dust is formed. In this respect it is very different from 
much-rotted cypress wood. In the latter the chemical 
transformation is far from uniform. Diseased Libocedrus 
wood is changed throughout; both the spring and the sum- 
mer wood are changed, and very rapidly at that, i. e., 
there are no intervening steps as in Taxodium. <A section 
made through the edge of a diseased pocket shows that at 
a certain point the cells are brown (Pl. 4, fig. 2). It 
will be noted that the color of fig. 2 is the normal color of 
the wood. Hand in hand with this coloration goes a shrink- 
age of the middle lamella, so that the walls of the tracheids 
become much thinner. They have lost all tenacity. If a 
piece of charred wood is boiled in water for a few moments 
it can be pressed into any shape like a piece of dough. 
Sections on a slide can be pushed about so that the cells 
assume a rhomboidal shape, i. e., the whole acts like a net- 
work of fine flexible wire. This is to some extent visible in 
Pl. 4, fig. 2, where a number of the walls are much bent, 
and do not have the rigid appearance of the healthy wood 
* Penhallow, D. P. Generic characters of N. A. Taxaceae & Coni- 
ferae. (Trans. Roy. Soc, Canada ii. 2; 51. 1896.) 
48 
