XUTK (IX I'OI.) PORIS LCCinrS LKVSS. 



50«J 



rouoii, (j.j-ii.o, ^.2-j.^i) IX, o\oid, truncate at base. Tlie .-^pure 

 has a li valine membrane or epispore which projects l)eyond the 

 coloured endos]K>re at the base, and it is the colla])se of this 

 empty base which gives the sjx^re the truncate appearance. 



A section (Fig. 3) shows that the hyph?e of the laccate 

 cuticle forms an even, ctnnpact palisade tissue comjiosed of cells 



Fig. 3. 



growing vertically upwards and becoming swollen at their ends, 

 where they are thicker walled and darker in colour than the 

 ordinary hyphae of the trama. 



The pores appear beneath a layer of downy hyphse which 

 covers the hymenium. The surface may be perfectly smooth 

 with no indications of pores, but when the outer layer is re- 

 moved the young jwres, often already of some depth, become 

 evident. Fries made use of the development of the pores as 

 one of the characters in distinguishing Polyporus from Poly- 

 stictiis and Tratnetcs. In the former, he held that the pores were 

 preformed (endogenous), and thus at first covered by a smootli 

 contiguous layer, whereas in the latter two genera the |X)res were 

 supposed to arise successively from the centre outwards and to 

 be open from the beginning (exogenous). 



It has since become extremely doubtful whether the de- 

 velopment of the pores is of any value in classification, and 

 Miss Ames* writes : " Judging from the forms examined, there 

 is not sufficient difference in the order of development of the 

 pores for it to be used as a character in classification." 



I have not had the opportunity of following the complete 

 development of this fungus, which in the very young stage 

 consists of a white-greyish, soft, corky nodule (plate i6a), the 

 interior of which is brown and striated and covered by a white 

 rim about .5 mm. thick. Whether the nodule would become 

 hard and pass into a kind of resting condition capable of re- 

 suming growth on the return of favourable conditions if growth 



* Ames, A. A. : " Consideration of Structure in Relation to Genera 

 of the Polyporaceae," Ann. Mycologici. 11 (iQi.^^- [33- 226. 



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