VIl] BASIDIOMYCETES. 211 



Lower Coal-Measures as Rhizomorpha Sigillariae^, bears a strong 

 likeness to some insect-burrows, such as those of Bostrychus. 



"A new fungus from the Coal-Measures" described by 

 Herzer in 1893^ may probably be referred to animal agency. 

 In any case there is no evidence as to the fungoid nature of 

 the object represented in the figure accompanying Herzer's 

 description. 



More trustworthy evidence of fossil fungi is afforded 

 by the marks of disease in petrified tissue and by the 

 presence of true mycelia. In examining closely the calcareous 

 and siliceous plant-tissues from the Coal-Measures and 

 other geological horizons, one occasionally sees fine thread- 

 like hyphae ramifying through the cells or tracheal cavities ; 

 in many cases the hyphae bear no reproductive organs and 

 cannot as a rule be referred to a particular type of fungus. 

 If the hyphal filaments are unseptate, they most likely 

 belong to some Phycomycetous species ; or if they are obviously 

 septate the Mesomycetes or the Mycomycetes are the more 

 probable groups. Occasionally there may be found indications 

 of the characteristic clamp-connections in the septate filaments ; 

 a small semicircular branch, which is given off from a mycelium 

 immediately above a transverse wall, bends round to fuse with 

 the filament just below the septum, thus serving as a small 

 loop-line connecting the cell-cavity above and below a cross wall. 

 Such clamp-connections are usually confined to the hyphae 

 of Basidiomycetes and thus serve as a useful aid in identi- 

 fication. A good example of a clamp-connection in a fossil 

 mycelium is figured by Conwentz^ in his monograph on the 

 Baltic amber-trees of Oligocene age. The stout and thick type 

 of hypha found in some fossil woods agrees closely with that 

 of Polyporus, Agaricus melleus and other well-known recent 

 Basidiomycetes. 



In a section of a piece of lignified coniferous wood recently 

 brought by Col. Feilden from Kolguev island ^ the brown and 



1 Lesquereux (87). ^ Herzer (93). » Conwentz (00) PI. xii. fig. 5. 



-» Feilden, H. W. (96) ; Seward (90^) p. 62, appendix to Feildon's paper. I am 

 indebted to Dr Bonney for an opportunity of examining the plant remains from 

 the Feilden collection. 



14—2 



