DEPALLENS. 



the hollow cypress trees are caused by this fungus, in which case it causes much 

 damage and a serious loss to the lumber trade. 



Compare Auberianus, glabrescens. 



FOMES LIGNOSUS (Fig. 580, Polyporus form). Pileus ap- 

 planate, usually thin, 1 to 2 cm. thick, rarely of a truly Fomes form, 

 4 to 6 cm. thick, with many annual layers. Surface reddish brown 

 when fresh, smooth, even, but drying with narrow, sulcate zones. 

 Flesh white, becoming yellowish in old specimens. Pores minute, 

 bright orange on the growing surface, but fading out below. Spores 

 never found by me. 



This is a most common plant throughout the tropical world, and has had 

 many names. It is a distinctive disease of the rubber tree, attacking and destroy- 

 ing the tap roots and causing the death of the tree. We are told that in rubber 

 countries it is quite a pest, and is all the worse because the mycelium attacks the 

 roots of the tree and is not found until the damage is done. We have an account 

 and figure (reproduced Fig. 581) in Myc. Notes, page 519, and Prof. Fetch gives 

 a full account in his "Diseases of Hevea" and a colored figure under the misname 

 Fomes semitostus. 



Fomes lignosus rarely takes true Fomes form. Usually it is thin, growing 

 imbricate, and would be sought as a Polyporus (Fig. 580). Often it is resupinate, 

 over large extent, and these resupinate pieces contract and curl in drying. The 

 curious feature of the pores losing the color in the older portions only, is, as far as I 

 have noted, peculiar to this species, and by this feature I can tell the species at sight. 



ILLUSTRATION". Fetch, Diseases of Hevea, frontispiece, Mycological Notes, page 519, 

 Fig. 515. (Reproduced Fig. 581.) 



Compare Auberianus, diffusus, Kamphoveneri, microporus. 



NOTE. Polyporus zonalis, a true annual, is a close relation of Fomes lignosus, and not always 

 easy to tell from young Fomes lignosus. The coloration and surface of pileus is the same, but the pores 

 do not fade out. Spores globose, 4-5 mic. are usually found in Polyporus zonalis, and never found 

 in dried specimens of Fomes lignosus to my knowledge. 



FOMES FRAXINEUS. Pileus applanate, with a pale, hard, 

 dull surface, becoming brown when old. Context at first soft, punky, 

 white (or pale), at length hard, ligneous. Pores small, round, the 

 tissue pale with a faint pinkish tinge. Spores (W) subglobose, 5x6. 



This is a frequent species in Europe on ash, apple, locust, and 

 other frondose wood. It sometimes attains a very large size. We 

 take it in the sense that it has become established by use, although 

 not correct historically, for Fomes fraxineus originally with its colored 

 pores was no doubt the same as Fomes ulmarius. It is closely allied 

 to ulmarius, and has been generally confused. Berkeley seems to 

 have been the only one who appreciates the real difference. He 

 called this plant Fomes cytisinus, which in justice is the correct name 

 for it. In America Fomes fraxineus is quite rare, and I have never 

 seen anything but the earlier punky forms, and they are doubtful. 



ILLUSTRATION. Sowerby. t. 288 (as Boletus suberosus). 

 Compare cytisinus, incanus. 



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