16 



of the fomentarius type, flat, hoof -shaped, very hard, upper surface 

 at first yellow brown, then becoming fissured and black; hymenium 

 yellow brown, with numerous small, round pores, which extend out 

 over the edge and partially onto the top of the pileus; found on Junip- 

 enis virginuina in Kentucky and Tennessee.^ A study of other spec- 

 imens, only two of this Polyporus having yet been seen, may prove 

 that these characters are not constant, in which case the form should 

 be considered a form of Polyporus fome7itarlus. 



RED ROT, OR PECKY CEDAR {Polyponis cameus). 



General characteristics.— This disease is perhaps more common than 

 the white rot. It has been found in Missouri, Arkansas, Kentucky, 

 Tennessee, Virginia, and Kew York; has been reported from Missis- 

 sippi; and has been received from Bermuda on the wood of Juniperus 

 lermudiana, which shows the disease in marked form. It doubtless 

 exists in other States in which the cedar grows in quantity. The 

 wood of arbor vit« {TJiuya occklentalis) found in Maine by the writer 

 often had the characteristic ])rown pockets. Wood afiected with this 

 disease is full of pockets. (PI. V.) In the early stages these are free 

 from one another and are more or less filled with a brown metamor- 

 phosed wood substance which has cracked so as to form small cubes 

 adhering to the walls of the pockets. The pockets are of difierent 

 sizes, varying in length from 1 inch to several feet. In cross section 

 they are nearly circular when small, but become very irregular when 

 old. (PI. VI.) Frequently a number join and make large, irregular 

 holes, full of the brown wood. The latter has the appearance and 

 properties of brown charcoal. It is very brittle and can be ground 

 into an impalpable powder in a mortar. When boiled in water it 

 acquires the consistency of cheese and can be cut with ease and readily 

 compressed into a small volume. A mass of wood thus changed has 

 the appearance of clay suddenly dried, which has split in the center 

 and laterally into more or less regular pieces. The line of demarcation 

 between the brown wood and the normal heartwood is very sharp. If 

 the brittle wood is broken away the remnants of it can be scraped oflf, 

 so as to leave the surface perfectly smooth. A very slight downward 

 pressure on one of the cubical pieces will cause it to break ofl' entirely. 

 The specific gravity of the material is very much less than that of the 

 cedar wood, and it absorbs water with great ease. 



CHAN-GES WHICH THE FUNGVS CAUSES IN THE WOOD. 



The structural changes caused by the fungus in the wood are but 

 slight, but the chemical changes are very great. When cut into sec- 



1 A fungus has been reported from the Devonshire swamp, Bermuda, which may 

 prove to be this form on /. bermudiana. 



