184 PAUL C. STAND LEY 



On the summit of the plateau through which the canyon 

 runs are many wide treeless expanses, thickly covered with 

 grasses and other herbaceous vegetation. Here and there 

 through the meadows are small ponds and sluggish streams 

 bordered with sedges (Carex sp.). The ponds often contain 

 Sparganium angustifolium, Callitriche palustris, and two species 

 of Lemna. The meadow grasses are the tall-growing Festuca 

 thurberi, Poa interior, Danthonia intermedia, Stipa lettermanii, 

 Sitanion californicum, and Phleum alpinum. Dugaldea hoopesii, 

 Pyrrocoma crocea, Veratrum tenuipelalum , and Campanula petio- 

 lata are abundant and showy plants. 



It is along the small brooks tributary to the Brazos and 

 having their source in springs at the foot of the escarpment of 

 the plateau that herbaceous vegetation is rankest. Some of 

 these streams fall down over rounded boulders; others have 

 cut deep and narrow channels through the soil among the trees, 

 often spreading out to form swamps. Characteristic of these 

 hydrophilous plants are Aster canbyi and A. burkei, Aralia bi- 

 crenata, Viola nephrophylla, Rumex occidentalis , Crunocallis 

 chamissonis, Panicularia pauciflora, Calamagrostis canadensis., 

 Actaea viridiflora, Aconitum bakeri, Rudbeckia laciniata, Cap- 

 noides brandegei, Senecio chloranthus, Epilobium novomexicanum, 

 Ligusticum porteri, Conioselinmn scopulorum, Alsi?ie baicalensis, 

 Sagina saginoides, Sanicula marilandica, Heracleum lanatum, 

 Cirsium pallidum, Castilleja sulphur escens, Humulus lupulus 

 neomexicana, Geum oregonense, Streptopus amplexifolius, Cynthia 

 viridis, Hydrophyllum fendleri, and Mimulus pubescens. The 

 wild hop is very abundant on rocks along the brooks, and equally 

 so is Aralia bicrenata, which gets to be four feet high or more. 

 One of the most conspicuous plants is Athyrium cyclosorum, 

 forming great clumps at the very edge of the water. 



Mosses and lichens are abundant in this zone, as to number 

 of individuals if not of species. The rocks along the streams 

 are usually carpeted with mosses. Lichens are not frequent 

 on the trees, although a species of Usnea is conspicuous locally, 

 hanging from the branches of the spruces; but rock lichens are 

 very abundant, covering the faces of the cliffs and the loose 

 rocks of the talus slopes. 



