100 JOURNAL OF THE ARNOLD ARBORETUM [vol. ii 



Baccharis Wrtghiii Gray. 

 A low shrub in open situations in the canyon and on the upper plains. 



Bigelovia pulchella Gray. 



On rocky banks of Upper and Lower Cap-rock zones. 



Bigelovia graveolens (Nutt.) Gray. 



A diffuse shrub, one to one and a half metres high, with densely canescent 

 foliage and stems. Grows on calcareous or gypseous banks of Upper and 

 Lower Cap-rock zones. 

 Bnckellia W right ii Gray. 



On dry banks in Upper and Lower Cap-rock zones. 



Artemisia jilif alia Torr, 



Often common in sandy open situations on the upper plains, and some- 

 times found in the canyon from the Upper Cap-rock zone to the canyon 

 floor. 

 Clematis Simsii Sweet. 



Found in deep-watered side canyons. Not common. 

 Celastrus scandens L. 



The Bittersweet vine was noted in only one locality, in a protected situa- 

 tion at the head of a deep side canyon. 

 Vitis Longii Prince. 



Commonly grows as a low shrub a metre or so high in the protection of 

 low bluffs in the Upper Cap-rock zone. In the deeper side canyons and 

 along bluffs of the Lower Cap-rock talus zone it sometimes becomes a vine 

 several metres high. This species is also very abundant, in the shrubby 

 form, in the deep sands bordering tlie Canadian River, farther north. 

 Vitis rnpestris Scheele. 



Low bushy plants, which from the leaf form appeared to belong to this 

 species, were found at one point in the talus below the lower cap-rock. As 

 there was no fruit it may possibly be only a form of the last-named species. 



From the foregoing list it will be seen that the assemblage of woody plants 

 in the canyons is a rather heterogeneous and remarkable one. It must be 

 remembered, too, that even here the trees and shrubs constitute only a 

 small proportion of the entire flora. Wliile it is not within the province of 

 this article to enter into a detailed description of the non-ligneous plants it 

 may be noted that they appear to have been drawn from no less varied 

 sources and an investigation of them may contribute largely to an under- 

 standing of the origin of the trees and shrubs with which tliey are associ- 

 ated. In the protection of high bluffs and at the heads of deep canyon 

 branches, where perennial springs afford a considerable supply of water, the 

 herbaceous growth becomes in places quite luxuriant. Dripping banks are 

 clothed with the Venus* Hair fern {Adiantum Capilli{s-Vencris) ; there are 

 mossy ledges and boggy beds of Equisetums, rushes and the tall plumy 

 grass, Phragmites communis, and many other surprises in moisture-loving 

 plants are encountered. Their presence in these canyons in the midst of the 

 grassy plains, associated with a comparatively rich ligneous flora, and so 

 far removed in many cases from the main body of their kind and kindred. 



