169] FLORA OF BOULDER, COLORADO 21 



Of herbs the vetches and vetchlings are the most im- 

 portant : 



Vicia sparsi folia V. producta 



V. dissitifolia Lathyrus leucanthus 



V. oregana 



f. Vallicolae. The mesa canon has a bewildering di- 

 versity of floral elements, now consisting of thickets of haws 

 with extremely vicious thorns, wild briers, the long-beaked 

 hazel, and dwarf maples, now with a fontinal vegetation 

 strikingly like our own Carolinian. One little gulch at the 

 base of Flagstaff Hill has a vegetation composed quite wholly 

 of eastern plants. Here occur Phragmites Phragmites, Sani- 

 cula Marilandica, Steironema ciliatum, Veronica Americana, 

 Eupatorium maculatum, and a form of Apios Apios, the last 

 of which was not known to occur west of eastern Kansas 

 previous to this collection. Since the streams have cut deeply 

 into the surface, the canon of the mesa resembles greatly the 

 canon of the foot-hills. There are riparian, rupestrine, clivose, 

 and fontinal elements compressed within the space of a few 

 feet. Mountain forms follow these streams often for some 

 distance into the plain. And yet the facies of the flora is dis- 

 tinctly eastern. Here are haws, hazels, maples, grapes, wild 

 cherries, willows, cottonwoods, dogwoods, nine-barks. The 

 herbs, too, have an eastern look sweet cicelies, false Solo- 

 mon's seals, water-leafs, fragile ferns, avens, bog-orchids. It 

 is true that a closer examination reveals the fact that many of 

 these plants belong to species which are strictly western, yet the 

 fact remains that there is little in the vegetation that impresses 

 as strange, one who is familiar only with the eastern flora, 

 while all about him in plain, mesa, foot-hill, and mountain are 

 utterly unfamiliar types of vegetation. So in this narrow 



