72 THE PLANT CELL WALL 



erties of the eugenol lignin formed in Psilotum and Marchantia. 

 The synthetic lignins of Polytrichum, Rhodobryum, Jungermannia 

 and even the basidiomycete Boletus are virtually identical spectro- 

 scopically with the substances formed in angiosperm tissues. Equi- 

 setum, Selaginella and Bryum give similar products. Only the 

 first-mentioned species differ markedly, although one must conclude 

 that commonness of precursor by no means limits the product 

 formed and may allow for considerable latitude in the specific 

 nature of that product. 



The existence of such variation as a reflection of matrix effects 

 may be seen in a comparison of dioxane-soluble eugenol lignin 

 formed on chitin (a max 270 nuji), cellulose (X max 280 my.) and 

 the mineral amphibole (X max 315 m.[i). 



A comparison between native and eugenol lignins shows us 

 that they are spectrophotometrically identical in Psilotum; some- 

 what different (as discussed) in the angiosperms and Equisetum; 

 and moderately to greatly different in other cases. 



Of the twenty-two species studied, nine contained conspicuous 

 quantities of lignin and four only trace quantities. Experimentally, 

 fifteen species could form appreciable lignins from eugenol when 

 supplied peroxide and one additional species did so in the absence 

 of peroxide. Of the seven fungi, only one converted eugenol to 

 lignin. Polyporus, which actually contained lignin in the sporo- 

 phore, could not synthesize it under any experimental conditions. 

 Such paradoxical behavior may be accounted for by the additional 

 facts that the organism was actually found thriving on a fallen 

 oak, hence may contain derivatives of host lignin either intact or 

 repolymerized from solubilized fragments which had diffused into 

 the mycelium. 



What can be learned about lignin phylogeny, then, from, such 

 experimental studies? First, we can recognize a most important 

 point, namely that the capacity to form lignified cell walls exists 

 in species which lack lignin or contain limited amounts in highly 

 specialized tissues. As a corollary, we may note that this potential 

 goes beyond the vascular plants, although it may not exist commonly 

 in the fungi. 



