284 George E. Nichols, 



The bryophytes and lichens of the climax forest. — Corticolous 

 mosses and liverworts form a striking feature of these forests. 

 Loose mats of Neckera and Leucodon, Porella and Frnllania 

 often literally plaster the trunks of maple and other trees ; Ulota 

 grows in scattered, compact tufts, particularly on trunks of 

 beech; while two lichens, Sticta pulmonaria and Parmelia saxa- 

 tilis, are of very common occurrence. Tree bases, logs and rocks 

 also are usually hidden by masses of Baszania, Anomodon and 

 various Hypnaceae. A list of some of the more conspicuous 

 species follows : 



Bazzania trilohata cc Thuidium delicatulum cf 



Ptilidium ciliare cf Brachythecium reflexiim cf 



Porella platyphylloidea cc Rhytidiadelphus loreus fc 



Frnllania Tamarisci cc Rhytidiadelphus triquetrus fo 



Dicranum longi folium ff Hylocominm splendens cf 



Dicranum scoparium cc Hylocominm wnhratum cf 



Ulota ulophylla cc Ptiliiim crista-castrcnsis co 



Mnium cuspidatum cc Stereodon cupressiformis cf 



Leucodon sciuroides cf Hetcrophyllon Haldanianum cf 



Neckera pennata cc Hypniim Schrcberi cf 



Heterocladium squarrosulum cf Webera sessilis fo 



Anomodon atteniiatus ff Polytrichum ohioense cf 



Leskeella nervosa co 



But while mosses and liverworts are present in profusion in 

 these deciduous climax forests, it is important to note that they 

 develop luxuriantly for the most part only on substrata which 

 are elevated above the general level of the forest floor. On the 

 forest floor itself the bryophytes usually are sparsely represented 

 and they may be totally absent over considerable areas. This 

 is in striking contrast to the conditions which prevail in the 

 evergreen coniferous climax forests of the highland, where the 

 ground is almost always carpeted by a rich growth of bryophytes. 

 Various explanations for this dissimilarity have been considered 

 by the avithor. At first it seemed that it might be due to differ- 

 ences in soil acidity, but all the forest soils tested were found to 

 be more or less acid to litmus. Similarly, differences in light fail 

 to afford an adequate explanation. The conclusion has finally 

 been reached that the scarcity of mosses and liverworts on the 

 forest floor in deciduous forests is correlated in large measure 



