386 E. LUCY BRAUN 



secondary species of lichens are present, most prominent of 

 which is the gelatinous lichen, Omphalaria sp. Mosses become 

 more important, both in numbers and species, than in the crus- 

 tose lichen stage. Grimmia apocarpa, Anomodon attenuatus, 

 and Leskea sp. are represented, and in places become so abun- 

 dant as to interfere with the lichens, thus indicating the next 

 stage in the succession. The aspect of the foliose lichen stage 

 changes from place to place. Omphalaria is sometimes the 

 facies of the association. In places the foliose lichens are not 

 well represented, and the mosses of this stage assume greater 

 prominence, though scarcely more abundant. 



Fruticose lichens are entirely absent from the succession, 

 which in this respect differs from rock successions described 

 elsewhere. 2 



On the undersides of overhanging ledges and on many rock 

 faces protected from direct light, none of the characteristic 

 lichens of the two preceding stages are seen. In their places, 

 is the pale powdery lichen, Amphiloma lanuginosum, and rarely 

 a light green moss, Plagiothecium sp. The sharp color contrast 

 between the dull grey-greens of the lichen communities or the 

 dark rich green of the moss mats, with the pale yellowish green 

 of this lichen is often very striking. In very sheltered spots 

 the Amphiloma sometimes grows with the mesophytic mosses 

 and occasionally overruns them. 



2. Moss stages. The first mosses appear early in the lichen 

 stages of the succession, but it is not until after the foliose lichen 

 stage is well advanced, that they become prominent. 



The first well marked moss stage is dominated by Anomodon 

 attenuatus, with Leskea sp., Anomodon minor, Grimmia apocarpa, 

 and the liverwort, Porella platyphylla, as secondary species. 

 Crustose and foliose lichens persist in spots. Grimmia is the 



2 Cooper, W. S. The ecological succession of mosses, as illustrated upon Isle 

 Royale, Lake Superior. Plant World 15: 197-213. 1912. 



Cooper, W. S. The climax forest of Isle Royale, Lake Superior, and its de- 

 velopment. Pt. II, The successions. Bot. Gaz. 55: 1L5-140. 1913. 



Fink, Bruce. A lichen society of a sandstone riprap. Bot. Gaz. 38: 265-284. 

 1904. 



