274 CALIFORNIA ACADEMY OF SCIENCES. 



The water from the mesa above sinks to the underlying 

 strata, and there on a narrow bench, not more than a yard 

 wide, constantly oozes out. Here is a most strange veg- 

 etation, a boreal oasis in the midst of a sonoran desert. 

 It was in this place that Aquilegia micrantha was first dis- 

 covered by Mr. Alfred Wetherill, who now took me to 

 the type locality, and here grew Primula farinosa, Soli- 

 dago Canadensis, Mimulus cardinalis, Oenothera biennis 

 grandijlora, Shepherdia rotundifolia and Epipactis gi- 

 gantea. How did these waifs reach that isolated bench, 

 with nothing in the surrounding country in the slightest 

 degree allied? Below, along the San Juan River was the 

 riparian vegetation common to rivers of the Upper Sono- 

 ran; above, on the mesas, the Mentzelia?, Gilise, Abroniee 

 and Eriogona were probably growing ; not another species 

 of Aquilegia or Primula nearer than the La Plata Mount- 

 ains, distant more than a hundred miles. Here, these plants 

 have been growing and blooming for ages probably, in- 

 dicating the character of the vegetation before the river 

 wore down the cliffs to the present level, an instructive 

 remnant of a past flora. Primula farinosa, Soli dago 

 Canadensis, Mimulus cardinalis and CE not her a biennis 

 grandijlora showed some deviation from typical forms, 

 but hardly sufficient to constitute even varietal distinction. 

 Aquilegia micrantha in its more numerously divided 

 leaves belongs, together with A. ecalcarata, to a section 

 quite distinct from other known Aquilegia?. The Shep- 

 herdia was seen again and has been collected in other 

 parts of the State. The Epipactis was not so different 

 from the common form as to be noticeable. 



Bluff City was reached late in the afternoon. The 

 men were off repairing the ditch. The San Juan had 

 suddenly shifted its course so that the entrance of the 

 ditch was left some distance from the water. I mention 

 this as illustrating the unstable character of the stream. 



