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7. The form, size, branching and septation of the mycelium. 
8. The relation of the hyphae to the cells and vessels. Do they 
penetrate between or through the tissue-elements? 
DRAW showing a few cells and vessels with the ramifying mycelium. 
This vegetative activity continues during the season. No conidia 
are formed in nature so far as known. Toward autumn the mycelium 
begins to form sporophores which break forth through the lenticels or 
cracks in the bark, as may be seen in the specimens provided. Examine 
the sporophores further and OBSERVE :— 
9. The velvety upper surface. Note the zonations and coloring. 
10. The lower or pore-surface. Note the numerous small pores; 
their form and size; color of the pore-surface. 
Make a prawINnG of a sporophore. 
Make thin cross-sections of the pileus and examine with high-power. 
NOTE -— 
11. That it is made up of interlacing strands of mycelium. 
12. The parallel columns which are the sides- of the tubes; 
lining these tubes the basidia bearing the spores. 
Make an outline DRAWING of the cross-section of a pileus to indicate the 
relation of parts. 
Carefully examine the hymenium and MAKE ovuT:— 
13. The club-shaped basidia, bearing at their tips four spores 
on short sterigmata. 
Make a large DRAWING of the hymenium showing its structure. 
These sporophores are not killed even by long drying and when wetted 
again mature and discharge more spores. A single mature sporophore 
will, if kept moist, continue to discharge spores for more than two weeks. 
The mycelium lives over in the rotten tissues and, spreading into 
adjoining sound wood, continues the destruction and produces a crop of 
sporophores year after year until the post is destroyed. 
Pathological Histology. In order to more clearly understand the 
changes which have taken place in the rotted wood, a study of the normal 
wood must first be made. 
Cut thin cross- and longisections of the healthy wood from the center 
of the blocks. Stain two minutes with methyl green and 45 seconds with 
congo red. Examine carefully. OBSERVE>— ; 
14. The large tracheae in the spring wood. Note the heavy 
walls of these ducts; within the tracheae, the cell-like structures. These 
are ingrowths of the walls of surrounding cells, now dead, and are termed 
tyloses. 
z 15. The heavy-walled wood-cells surrounding the ducts. 
16. The medullary rays between the xylem-wedges. The methyl 
green stains the lignified tissues; and the congo red, the tissues the walls 
of which are partially or wholly of a cellulose nature. 
Locate each of these in the cross- and longisections. Make a detailed 
DRAWING of a part of the cross-section to show the relation of the tissues, 
the size of the cells and the thickness of the walls. 
Now examine the similarly stained cross- and longisections of the 
decayed wood. OBSERVE :— 
17. The dense masses of mycelium in the tracheae and the 
absence of the tyloses. Compare the walls of the tracheae here with 
those in the sound wood. 
