ECOLOGY OF THE WALLULA GORGE. 29 1 



usually on the surface of rocks, Parmelia prolixia occupying the 

 better part of a square yard of the upper surface of a block of 

 lava in the shade of a sage brush. Parmelia coitspersa and P. 

 caperata were on the ledges, contending with the Grimmias for 

 a share of moisture. Umbilicaria phara generally stuck to rocky 

 faces, so situated that the disintegrating material could not fall 

 behind the thallus to pry it from the hold-fast. Of the fruticose 

 lichens Cladonia Umhriata was the only one seen. 



Besides Griminia calyptrata, with long, pointed leaves, were 

 found G. alpestris, G. leucophea and G. tencrriuia in scatter- 

 ing cushions ; TortuJa rnralis and T. aciphylla, generally lying 

 loosely on or in slight niches of the ledges, while along the 

 edges, on small lumps of humus, Encalyptra vulgaris, the big 

 Extinguisher moss, was sparingly scattered. West of the Cas- 

 cades the calyptra is fringed, hence Encalyptra ciliata. The Tor- 

 tulas sometimes grow in the upper stretches on soil of steep 

 gulches. On the sands, under sage brush, Desmatodon plin- 

 thobius sends up its yellow seta to fruit quickly and die. The 

 scarcest, though most interesting moss, is Pterigoneurum cavi- 

 folium, with its abnormally large capsules and abundant reddish- 

 brown spores. 



The higher plateaux are occupied by Artemisia tridentata, 

 which gives its peculiar hue to the " Sage Plains." On the 

 hills, among this sage brush, Gila gracilis is among the first to 

 put forth its tiny blue flowers, although the yellows always pre- 

 dominate. Among the most beautiful and hardiest of the Com- 

 positae is Aster amethystinus, growing along fence rows, the 

 flowering continuing into December. Another, not so large, with 

 the basal leaves 5-7 lobed and smafler violet rays, seemed to be 

 Aster fremontii. 



On the hills, Bigelozria graveolens offers some " brousi." On 

 the Nevada plains it is called " Rabbit brush," as it affords about 

 the only covert for the little cotton-tail, Lepiis hardii.'^ 



* For the determination and verification of the phanerogamia as well as 

 the cryptogamia the writer is indebted to his numerous friends who are 

 specialists along their several lines. In consultation a free use has been 

 made of A Flora of the Palouse Region, issued by the Washington Agri- 

 cultural College, Portland, Oregon, June 9, 1906. 



