Re: missouriensis

I found Dave Ferguson's comments about where he has observed *Iris missouriensis* growing, and especially his comments about other species with which it has been associated most interesting.
 
The areas in Idaho and Oregon where I saw the species are as Dave described--wet, even to the point of standing water, in spring, with dry to quite dry conditions late in the summer.  The species appears to have its active growth mostly in the spring, right along with bloom.  How far south into Mexico those conditions might be found in the periods of extreme advance of ice sheets and glaciation would determine the southern limit of the migration of *missouriensis* and co-extant species.
 
The stem heights Dave notes compare with my own observations.  The climatological factors governing moisture levels in New Mexico and surrounding areas and those in the Idaho/Oregon border areas are generally related, both varying with the El Nino/La Nina cycle and the rhythms of the North Pacific cyclic systems related to or possibly causitive of the tropical zone cycle.
 
The presence of some the species mentioned in Dave's post in the areas where I lived on the Idaho/Oregon border is a result of the near-extinction of the older ecological systems of the area with the rise of the Cascades and Sierra Nevadas, and now limited to stream traces carrying seasonal moisture down from higher elevations.  The remnant "Desert Canyon" flora having its origin sometime post-Miocene is very limited, the areas below having a flora derived from northward migration of species, such as *Artemesia tridentata*--the Great Gray sage, Ponderosa Pine and other plants associated with them, and the higher elevations having a Canadian alpine flora.  The "Desert Canyon" remanants contain some fascinating species, including one peony one would not recognize as such without botanical references at hand.  The native orchids are also associated with this flora.
 
One of the reasons the pond clays from Newfoundland, oddly, relate to those in the Basin and Range areas of Nevada and Oregon, as well as those near Dave and near the area I spent most of my earlier years north and west of him some 1200 miles or more all seem to vary with those systems in the Pacific.  This is not at all surprising, considering that the systems that bring moisture to the whole continental US originate in those areas of the Pacific both NW of Oregon and Washington, and in the SW of Central Mexico just north of the La Nina/El Nino zone at the Equator.
 
The rain today diagonally across the south and up to New York and New England begins as a disturbance in this area north of the Galapagos Islands.  Once the diagonally trailing winds sweeping NE-ward begin to cross waters south and east of Texas, the Gulf moisture gets added to that which manages to survive passage over the two Sierra Madre ranges, bringing a short-lived abundance to the southeastern US and on up the coast.
 
These patterns are fascinating to watch develop, wax and wane on maps put online by NOAA that reveal the weather patterns of most of the globe.
 
The long-term variations in these patterns are part of what govern the north-south and up-down migrations of climatic zones, which of those dominating depending on topography of the areas under consideration.
 
Neil Mogensen     z 7  western NC mountains

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