Re: missouriensis

The ecological anomaly of the Steens Mountain is considered geological, as it is evidently rising at a very rapid rate, or at least has in the recent past.  The evidence includes not only *Iris missouriensis* but numerous other factors, not all botanical, as well.
 
This could be true of some of the other anomalous areas of the Basin and Range province.  The continent apparently was moving (relative to some stable hot spots) toward the northwest, then some event caused a shift in vectors both for the Pacific plate and the North American, so that now the North American plate is now moving southwestward.
 
The "smile" form of what at one time was called the "Snake River Downwarp" or similar names is now understood to be an artifact of movement of the continent over the Yellowstone hotspot.  About ten million years ago the hotspot was under the Bruneau-Jarbridge area south of Boise, when a major series of eruptions deposited a substantial layer of ash as far east as Nebraska, burying large numbers of herbivores including cameloid species and relatives of the rhinocerus.  Conditions of the bones indicted serious lung/respiratory disease associated with strong atmospheric pollution, indicating that the hot spot, some 1600 miles away, was active for some time before the major "Bruneau-Jarbridge" events deposited several feet of ash on top of the Nebraska herbivores.  The outlines of a number of similar events march south-eastward from near Ontario, OR, to south of Boise, and gradually curving eastward, then northeastward through the area north of Twin Falls, ID to its present location under the Yellowstone National Park.  The eruptions of the "super volcano" resulting from the hotspot have a fairly regular periodicity of about 600,000 years.  The most recent major event was just about 600,000 years ago.  A few minor events have occurred in the past few tens of thousands of years, so a possible major eruption may be in the making. 
 
The University of Utah keeps close watch both on the Wasatch Front and the Yellowstone/Teton Range area for activity.  There is a constant stream of small to sub-medium earthquakes all along the front, and both in the Yellowstone caldera area and southwestward on the California/Nevada border in the area of Mammoth Lakes, another caldera of similar character.
 
It appears the area of the continent south of the "smile" in which tthe Snake River flows in Idaho is being stretched westward at a fairly rapid rate, causing a number of the ranges in Nevada to be rising as blocks tilt and stretch to allow for the continental movement.  The Steens Mountain block is not unique.
 
Oddly enough, another plane ride of interest is found in the flight from Boise to Denver.  The route sometimes followed allows the passengers on the left side of the plane to observe the Teton range in Wyoming from the south.  The range is the flared upward eastern edge of a large fault block the western side of which drops down into the "rototilled" trace of the Yellowstone Hotspot as it passed through the Idaho Falls/Rexburg area, collapsing the eastern side of the caldera downward as a vast amount of material was blown away by the massive periodic eruptions.
 
The Yellowstone Hotspot supervolcano is responsible for a major amount of rhyolite and ash deposits in every direction, but more eastward than westward.  The Owyhee area of SE Oregon has some spectacular scenery due to activity of the hotspot as much as twenty some million years ago.  The edge of continent has been substantially altered by accretion of terrenes (I'm not spelling that right, I believe) in California and states/provinces nortward including Alaska, so the entry point of the hotspot into the continent is obscured, but probably was somewhere near the Oregon-Idaho border, as layers point downward toward the trough in all directions except from the southeast toward the Ontario, OR to Caldwell, ID area, including from the north and northwest.
 
*Iris missouriensis* and the related *longipetala* in the San Francisco bay area are only two of several iris species affected by this complex of geological movements.  The entire PCN complex are products also. A study of the genus Pentstemon reveals similar patterns of movements and disruptions by the same events.
 
Neil Mogensen  z  7 western NC

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