Re: Re: missouriensis

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I caught a virus (well my computer did), so I've having a bit of trouble getting my e-mail in and out. 

 

This is an interesting subject, and I think it would be interesting to learn more about how past climatic and geological events may have affected this species and many others as well. 

 

I don't really know if there are any holes in I. missouriensis distribution in the Great Basin / Colorado Plateaus region.  It seems that I recall seeing it just about anywhere where habitat is reasonable (in the moister mountains).  Much of the lower elevation area in the region is too dry to support it except in isolated pockets, but the temperatures are fine for it.  I often here that it likes dry limey areas, but my experience is that it shows now strong preference for particular soils (except that it is rare on sand).  Also, it is found in wet places, generally in marshy "meadow" areas, or sometimes along seeps, along streambanks, or along lakeshores.  Some areas where it grows appear "dry" by summer or autumn, but moisture is very abundant in spring.  It is not uncommon to see it standing for part of the year in very shallow water, though usually not.  Sometimes it is found in the forest understory, but only where sunlight is abundant, most often with Aspen.  It is found at elevations equally as low as such species as Big Sagebrush, Gambel's Oak, Douglas Fir, Ponderosa Pine, Blue Spruce, White Fir, Gambel's Oak, Mountain Mohogany, Bitterbrush, Serviceberry, Narrow-leaf Cottonwood, Alder, etc., and it occurs upward through the elevations of subalpine Spruce, Fir, Aspen, and Lodgepole pine forests to often near or sometimes above timber line.   Parts of the southern Great Basin and the lower elevations of the Colorado Plateaus seem to be too low and hot for the species to be happy, even where water is available, and I've never seen it far out into the Great Plains from Wyoming and Nebraska southward. Southward from these regions the species is limited to the moister high elevation areas.  It is quite common in the mountains of New Mexico and central Arizona, mostly above about 7000 or 8000 ft.  It becomes more rare southward, as the desert mountain areas are mostly small and less able to generate their own moist conditions, and thus more prone to drought in extreme years (this also includes all of the Sierra Madre Oriental).  Few of these mountains are even high enough to support good Montane vegetation, though there are notable exceptions.  I'm not sure what limits it in the Sierra Madre Occidental, as you would think the area is good for it.  I suspect that in all of the mountains in northern Mexico the rainfall pattern is important.  The rainfall tends to be limited to summer and fall, and winter and spring are very dry (the opposite of what I. missouriensis seems to prefer).  It seems to me that I have seen it in west central Chihuahua and in the mountains south of Saltillo though, but I don't remember exactly where.  It has never been one of those species of plants I paid much attention to (it is a "grows everywhere plant").  I don't mean to talk ill of the species, it's just that my attention was always focused on other things more "novel" to a boy from Colorado, such as the Agaves, Cacti, Burseras, Palms, and so on; thoe ones that didn't grow in every meadow and pasture where I grew up.  If ever I get a chance to explore in Mexico again, Iris will be much more of a focus.  My sensitivities and interests have been expanded somewhat in recent years.

 

I. missouriensis is actually a pretty neat plant, at least when you really start looking close.  Every single plant is unique and different, with an endless variation in patterning and color combinations, even with the limited range of colors available.  Growing conditions can affect the plants dramatically.  I've often seen a meadow full of these beauties, in good weather conditions, producing a stalk from nearly every fan, and reaching an average of over 2 ft in height.  But, have come back to the same spot in a dry year to see perhaps fewer than a quarter of the plants in flower at all, and most stalks hardly over 10 inches (and the flowers much smaller too).  Even so, a pretty sight.  Your average herbarium botanists would likely consider two herbarium sheets from the same individual but from such different seasons as different species, if all they had to go on were the herbarium sheets and no knowledge of the living plants.

 

I got way off track from the issue of holes in distribution though.  I'd be curious where they are, and if they relate to such gaps as they occur in other species' distributions in the same regions.  I want to point out, for whatever it's worth, that several species are curiously lacking from huge areas in the Great Basin and Colorado Plateaus, and I suspect that periodic severity of climate may have more to do with it than geology.  I don't know the Steens well, but would suspect that they are not new enough to lack plants such as Iris and Ponderosa purely from being newly uplifted.  It would be very interesting to see how past geological events coincide with climatic events though.  Pinus ponderosa is absent from huge areas of the Great Basin and Colorado Plateaus, as well as much of the Pacific slope of the Rockies from Colorado and Utah northward.  Vast areas would seem perfect for it, yet it is not there.  Northward from Wyoming and Idaho, this might be explained simply by the climate simply being too cold, but southward from there, it doesn't really make sense based only on current climate.