How aspen use green ... or do they?

Our aspen are starting to flower but are still leafless.  Doesn’t matter, they can photosynthesize anyway.

New Under the Sun is hosting April’s Berry-Go-Round; the theme is plant color:

“You can talk about your favorite colors, unusual colors, pigment biosynthesis, how plants use color, how humans have painted new colors onto our favorite plants, color patterns, temporal color changes etc.”

This time of year, “plant color” makes me think of the bright flashes that start appearing in the drab brown-and-gray landscapes that have been with us all winter -- yellow sagebrush buttercups and purple pasque flowers and fresh green leaves popping from buds.  But even though Spring technically arrived over a month ago, it’s still late winter here.  There are occasional wildflowers -- a few brave individuals blooming -- but most are waiting. Trees are still leafless.  However, if you walk through aspen, a bit of green might catch your eye.

Quaking aspen, Populus tremuloides.  Notice it’s greener on the south side.

Some aspen trees have green bark.  It’s more obvious in younger ones.  In 1957, L.C. Pearson and D.B. Lawrence were living in Minnesota where green-barked aspen are common.  They looked at cross-sections of bark under a microscope and found that the green color was localized in plastids (compartments within cells).  This was intriguing, as others had suggested it was due to a parasitic fungus.  They realized that these were just regular plastids, not some abnormal growth.

A bright green layer visible through the very thin (0.2 mm) outer layer of bark.

They decided to investigate further.  They periodically collected bark and leaves from the north and south sides of aspen trees, extracted the green pigment, and analyzed it.  Absorption spectra for pigment from both bark and leaves matched that of chlorophyll, used by plants to photosynthesize and convert sunshine to food.  They also were able to show that the green pigment in the bark was photosynthetically active.

Absorption spectra of pigments in aspen dissolved in ether.  Data of August 3.  Chlorophyll a measured at 6600 A [peak on right].  From Pearson and Lawrence 1958; PDF available here.

Chlorophyll levels in bark were highest when leaves were just starting to appear, and then dropped off, suggesting green bark is a way to get a head start on the growing season.  Maybe this is why deciduous aspen can thrive where growing seasons are short ... where most other trees are evergreen conifers.

The bark is paler green in shady situations.

Before you go, let’s clarify one thing.  Contrary to what was suggested in the title, aspen don’t “use” green.  In fact most plants don’t -- they throw it away.  Chlorophyll is green because it reflects green light.  It absorbs red and blue for photosynthesis.  Here’s another spectrograph, this one in color so you can better see what colors plants use -- not green.

“Absorbance spectra of free chlorophyll a (blue) and b (red) in a solvent.”  Source

Acorn atole -- not a convenience food

Coast live oak near San Luis Obispo, California.  Photo by Giovanni LoCascio, used with permission.

The theme for March’s Berry Go Round is unusual edible plants, and all month I’ve had my ear to the ground for ideas.  Then last week while in California I read about Indians collecting, preparing and eating acorns.  I was struck by the oddity of it all.  I chose the coast live oak as my unusual edible plant but when I started to write, I realized there wasn't anything unusual about it.  Coast live oaks are common and the acorns are commonly eaten by wildlife.  They also were used by Indians to make a thick soup or mush, which the Spaniards called “atole” (ah-toé-leh) back in the 1700s.  It’s said to have been one of their most common foods.

Acorns of the coast live oak, Quercus agrifolia, were among the most prized for making atole.  Source

But times have changed and therein lies the explanation for why the oak seems an unusual edible plant.  In my world we rarely think about eating to survive.  Instead we search for food that's tasty, and usually convenient to prepare.  We wouldn't bother with acorn atole.

In fact, compared with atole, everything I eat is convenience food!  Converting tough bitter acorns to something edible was a long and tedious process.  Here’s a typical recipe, compiled from several sources (italics added for emphasis):

In fall, if the oaks have produced acorns, collect as many as possible, at least several hundred pounds.  Dry thoroughly in the sun and store.

Remove a small batch of acorns from storage, enough for the day.  In a stone mortar, grind a few at a time using a pestle or any suitable stone. When all acorns are ground, sift or winnow meal to remove coarse material.

Put the meal/flour in a depression in sand.  Rinse repeatedly with water.  This will require the greater part of a day unless hot water is available.  [Leaching removed bitter tannins.]

Pull out the sand-free center of the dough and bake as bread.

Use the remainder of the dough to make atole.  Mix with water in a woven bowl.  Drop in hot stones, stirring frequently to prevent scorching of the bowl.  Cook until desired consistency is obtained.

Methods of preparation varied somewhat.  Here Maggie Howard, a Paiute, shells and skins acorns into special baskets (Sierra Nevada, 1930s).  Elsewhere, acorns were simply dried and stored whole.  Source

“Grinding acorn meal.  A modern-day Indian woman gives a demonstration of the technique and tools employed by her forebears ...”  Source

Was atole tasty?  If so, maybe it was worth all that effort.  Saunders (1920) described the flavor as “rather flat but with a suggestion of nuttiness that becomes distinctly agreeable.”  Balls (1972) said it had a “slightly sweetish but rather insipid taste.”  Some visitors had problems with residual sand from leaching, and ash from the cooking stones.  But I think it's impossible for us to judge atole's appeal.  That was a place and time of limited fare, quite unfamiliar to us.

In any case, there were other reasons to eat atole.  Acorns are nutritious and rich in calories, especially compared with many wild plants.  They contain “up to 18 percent fat, 6 percent protein, and 68 percent carbohydrate” (CSUS no date).  They're large, and fairly easy to harvest.

Still, I was skeptical when I read that atole was an important staple, because acorns are so unreliable.  Oaks produce substantial yields only during mast years and these are unpredictable (Harper et al. no date).  This is good for the oaks.  During mast years, seed predators generally are swamped with food, and it's likely that some acorns will produce seedlings rather than be eaten.  However human seed predators had a counter-strategy -- storage.  Dried acorns are long-lasting, and Indians regularly stored them for several years or more (one source says up to a dozen).

Acorn woodpeckers also store acorns, but not as effectively as humans once did.  This one is stocking a "Granary Tree".  Source

Acorn atole has not disappeared.  It’s still prepared on special occasions, as a link to the past and in celebration of traditions and culture.  Fortunately, today’s cooks have access to modern conveniences:

“instead of the mortar and pestle, the electric blender or a meat grinder may be used to produce flour.  Cloth might substitute for the leaching basin, buckets may replace baskets, and a slow drip in the kitchen sink may flush the tannic acid.  For cooking, the stove and a metal pot might replace heated stones placed in baskets.  Whatever the preparation techniques, acorn is special: a tangible connection to the old ways, a nourishing food, and a commitment to the future” (from Past and Present Acorn Use in California)

Modern day mortar and pestle for making atole.  Source

NOTE:  Acorn atole is not related to the atole of Mexico, which is made from corn.

This month's Berry Go Round is hosted by Emma the Gardner.

Sources

Balls, E.K.  1972.  Early uses of California plants.  University of California Press.

California State University, Sacramento (CSUS).  No date.  Past and present acorn use in native California.

Harper, J.M. et al.  No date.  Acorn production by California oaks.

Saunders, C.F.  1920.  Useful wild plants of the United States and Canada.  New York: McBride & Co.

Plant Revenge -- or is it?

So-called “fragile” prickly pear (Opuntia fragilis) takes revenge on an unsuspecting botanist.

As part of my work, I routinely dig up plants and press them flat.  So sometimes when I’m struggling to remove plant parts from my hair, clothing and skin, the thought crosses my mind -- “this is revenge!”

Getting scotch thistle (Onopordum acanthium) into a plant press requires caution and the right tools: brick hammer to dig up plant, knife to slice heads into pieces.  Click image for view of dangerous plant parts.

Plants have lots of vexing and painful parts -- spines, thorns, barbs, prickles, glochids, retrorse hairs and dangerously-sharp leaf tips.  As biologists we assume these are adaptations, but for what?  It’s tempting to think defense.

The leaf tips of Agave lechuguilla, shin dagger, can be deadly.  From USDA Plants.

Retrorse barbs of wild licorice (Glycyrrhiza lepidota) look nasty ...

... but they're only a few mm long, as seen here in context (dog fur).

Retrorse spines and barbs make plant parts difficult and painful to remove, but their purpose could be considered noble -- to send offspring out into the world.  Wild licorice is very effective at dispersing seed this way, as my dog frequently demonstrates (see Leaving Home).  [retrorse: (Botany) (esp of plant parts) pointing backwards or in a direction opposite to normal]

Puncturevine nutlets are especially devilish (Tribulus terrestris; source).

The fruits of puncturevine also have barbs, but they're so hideous that I have to think their purpose is evil.  The plants grow low to the ground, often over large areas.  When the fruits dry, they split into hard nutlets with nasty sharp little spikes that are very good at attaching to feet and tires.  They puncture the feet of whatever passes through the patch; walking then becomes extremely painful.  Removing nutlets with ones mouth (what else can most animals do?) makes the situation even worse, and can cause death.  This seems over the top.  Do these structures really aid in dispersal if they cause us to avoid the plants?  So perhaps they’re weapons “for” defense -- but do they increase chances of survival given that we kill the horrid plants wherever we find them?

Puncture vine mat and closeup of flower.  Flowers are 0.5-1 cm across.  Source.

The most infamous pain-inflicting plants in North America are cacti, with their diverse assortment of spines.  Surely they are adaptations to discourage animals from eating the delectable fleshy stems, so appealing in deserts.  This is a reasonable conclusion.

Prickly pear cacti have tiny very sharp spines called glochids below the regular spines.  They're especially difficult to remove from skin.  Some cultivars are spine-free -- these are the tasty nopales or indian figs.

However there seem to be other “purposes” for cactus spines as well as defense. Consider that they’re found mainly in deserts -- plants of moister regions are rarely covered with spines.  Might spines shade stems and reduce water loss?  For the fragile prickly pear (beginning of post) and the infamous jumping cholla of Arizona (below), they appear to be "for" dispersal.  Stem segments readily disarticulate, and can attach to an unsuspecting passerby thanks to the spines.

Though many purposes can be conjured up by a curious partially-informed mind, it’s difficult to know why a plant structure evolved -- what it’s an adaptation for.  We rarely understand the evolutionary history of adaptive traits.  For example, something may have evolved for an unknown purpose long ago, and later was co-opted or redesigned for something else.  The opportunities for speculation are infinite.  There’s a thought-provoking discussion about this dilemma at The Mermaid’s Tale:  Why do cholla cacti use torture?, written by Anne Buchanan after a hike in the Arizona desert.

“The problem is that there may be no single reason, nor even any single kind of history involved here.  ... we think this illustrates why, even when the assumption that the trait is 'adaptive'--that is, is here ultimately because of natural selection--that assumption is hard to prove and in particular the reason is hard to be sure about.”

[Warning:  the included video featuring an unfortunate victim of cholla torture is not for the squeamish.]

Jumping cholla, Cylindropuntia fulgida.  Source.

Obviously we need to be cautious, not just in walking through dangerous plants but also in thinking about them.  Like so many biological phenomena, the more we learn, the more complicated it gets [sigh] but of course that makes the stories even more wonderful!  Here’s a great example:

Bullhorn acacia, Acacia hindsii.

The bullhorn acacia is a well-armed desert tree, with long spines that deter browsers in ways both obvious and surprising.  Obviously the sharp-tipped spines discourage larger animals, but they don’t do much against insect pests and fungal pathogens.  Fortunately they also serve as ant homes, and in fact, the acacias strive to make the neighborhood attractive to ants by providing nutritious food via extrafloral nectaries.  It’s worth the investment.  The ants sting anything that tries to eat the leaves, from caterpillars to cattle.  Furthermore, acacias with healthy populations of the right kind of ant have a reliable supply of antibiotics to fight fungal infections on their leaves.  Their drugs are produced by bacteria living on the ants’ legs.  What a nice arrangement!  For more, see The Economist, Protect and Survive; and Science Daily, Ants protect acacia plants.

✿✿✿✿✿✿✿✿✿

This post is my submission to this month’s Berry Go Round, a blog carnival for plant lovers.  It’s hosted by Garry Rogers, and the topic is Botanical Warfare.

Spines are for beauty too -- for those who look close (from Excruciatingly Beautiful).

Plants and War

Plants of the Sixties practiced non-violence.

Happy February, phytophreaks.*  It’s time to start thinking about a post for the monthly Berry Go Round, a blog carnival for plant lovers.  Host Garry Rogers has chosen a thought-provoking theme highlighting the sordid side of plants -- "Botanical Warfare." Plants mooch, defend, invade, injure, prey, poison and more.  This is fertile literary ground, so let your thoughts run grow wild!

*phyto - combining form, indicating a plant or vegetation

Send your posts to the carnival via an online submission form or a tweet, as explained here.  And do be safe in your botanical adventures!  Some unexpected phyto-danger may be lurking around the next bend ...

A Carnival of Rocks and Plants

Tors of Sherman granite with spring wildflowers.  This was May 2012; for now we can only dream.

In December we had a cross-cultural carnival for geologists (The Accretionary Wedge) and botanists (Berry Go Round).  Sadly, attendance was meager.  Perhaps it was the holidays -- certainly the case for me, that’s why this summary is a bit late.  Hopefully it wasn’t the topic.  In any case quality made up for quantity, for one of my top favorite natural phenomena received the most attention -- substrate specificity in plants!

Geotripper describes the situation that caused me to fall in love with plants addicted to rocks -- endemics on serpentine, rare plants on rare rock.  What’s an endemic?  What’s serpentine?  He explains both, with great photos.

The Life-long Scholar also posted about plants and serpentine, specifically ferns that may be sufficiently addicted to serpentine to serve as clues to geologic structures otherwise hidden by all that pesky vegetation.

My current favorite edaphic endemics are the subject of my post about calciphilic plants, those that seem be restricted to limestone or dolomite.  I’m not as lucky as students of the serpentine flora.  Even though there’s a lot more limestone and limestone-loving plants in the world, literature and knowledge are sparse compared with serpentine.

Serpentine ecology has literature to die for! (click on image to see just a few examples)

Colorado Lichens (and Friends) writes about a “plant” named for its habitat:  Rock Tripe.  This group of lichens includes a species that may have set the course of our county (USA)!   They’re certainly photogenic in any case.  I’m glad to have learned about this site “speaking of lichens mostly, sometimes mosses and other cryptogams.”  In addition to blog posts, it has lots of information about lichens, something I’d like to learn more about.  I was especially happy to find a tribute to substrate specificity:  Lichens and Rocks, a post in progress.

Lockwood of Outside the Interzone posted a good example of the curious and puzzling patterns of discontinuous distribution that plants present to us.  And we can’t resist asking ... why?!  In this case, why are there trees on only one slope of the crater?

Lockwood also contributed a post about amazing root systems of large spruce trees now exposed on a beach in Oregon.  These massive roots are all that’s left of the trees.  Geology, specifically plate tectonics, is to blame!

Plant bloggers at Berry Go Round were not restricted to topic, as the BGR carnival generally does not limit contributions beyond being botanical (though not gardening).  So in the next posts, we have a nice diversity of topics.

In Appreciating English Ivy, Tim at Notes of Nature discusses whether a plant is “good” or “bad” and when.  As much as some folks hate this ivy, it may well be a keystone species.  This is a thought-provoking post that caused my mind to wander beyond ivy (photo below).

We hate eucalyptus trees for replacing stands of native California live oak, but love them for providing habitat for monarch butterflies.  Photo by Benson Ricks, from Pismo Beach Monarch Butterfly Grove.

Dave Coulter at OSAGE + ORANGE brings up Yggdrasil.  Don’t know “Yggy”?  It’s a giant world tree, an interesting story in itself, and Dave also points out there may well be a connection to ash trees!

The Norns spin the threads of fate at the foot of Yggdrasil.

For my BGR contribution, I submitted the final post in a short series on autumn tree strategies.  Autumn seems so very long ago now!

Windrows of snow behind dead stems of bunchgrass, Laramie Basin.

To round out this summary, here are some interesting plant posts I found recently.   They’re a bit heavy on photos, but then live plants are what I crave this time of year!

Nature of a Man shared wonderful photos of California plants in the field including some serpentine species.  The photos are beautiful and natural enough that I almost feel like I’m there ... almost.

A Digital Botanic Garden posted exquisite photos of a beautiful legume, the broad or faba bean.

In case you haven’t already met, here’s a nice introduction to the Malpighiales, at Catalog of Organisms.

Floral odor and heat are how some cycads control pollinators -- telling them not just when to come but also when to leave.

Do you know the irresistible and popular titan arums?  Have a look at this one that bloomed in August 2012.  As its proud parents (US Department of Botany and US National Herbarium) explain, “its irregular flowering times, large inflorescence and foul odor still create a fascinating burst of fecundity.”  There's also a fun time-lapse video of the arum and its fans.

Favorites of mine, for their elegant flowers, are the milkweeds, featured at Through Handlens and Binoculars (with links to earlier posts).

Denver Botanic Gardens explains the Ikebana tradition of flower arranging in Japan.

Plants are not always nice, but for a good reason.  Defense is critical in a multitude of situations.  AoB Blog provides an interesting summary post and a link to Defence on demand: mechanisms behind optimal defence patterns

Also from AoB Blog -- does green always mean photosynthetic?  We know it’s not just leaves that photosynthesize, but are all green plant structures photosynthetic?

Quaking aspen get an early start.  Before leaves appear, the bark is photosynthesizing and flowers bloom.

Finally ... to all nature bloggers, I wish you the best in 2014.  And keep blogging!

Notes of Nature kindly provides monthly desktop calendars.  I especially like January 2014.

UPDATE (1/23/14)
Back in early January, Short Geologist at Accidental Remediation pointed out "If you are trying to locate pockets of soil deep enough to get a good non-surface soil sample, and you are ass-deep in boulders and cobbles and outcroppings," you might want to pay attention to the plants.  See plants and rocks for more.

Die Kalkfrage (the limestone question)

Limestone and dolomite in the Salt River Range of western Wyoming.  Photo by Hollis Marriott.

Shultz’s milkvetch (Astragalus shultziorum) grows in abundance on calcareous scree and rock outcrops in the Salt River Range (above), but overall it's rare.  It's restricted to several mountain ranges in western Wyoming and adjacent Idaho, and specifically to sites underlain by limestone or dolomite (images courtesy WYNDD).

Shultz's milkvetch, by Walter Fertig.

Distribution of Astragalus shultziorum in Wyoming.

In Wyoming, we have at least twenty species like Shultz's milkvetch -- restricted to limestone or dolomite.  Why?  What’s different about these plants?  This is the “limestone question" which has intrigued and puzzled botanists for more than 200 years. We call these species calciphiles or limestone lovers, though we really don’t know what we’re talking about (more on that later).  They’re endemics, meaning restricted to a limited area, and they're edaphic endemics as they occur only on specific soil/rock types.  Calciphiles are edaphic endemics that grow only on calcareous sites ... or so it appears.

It’s impossible to be a rare plant botanist in Wyoming and not be enchanted by our calciphilic plants.  They're often found in spectacular places, and the association with specific rock types is fascinating.

Shoshonea in foreground, on rocky calcaerous soil on Bald Ridge along the east flank of the Absaroka Mountains.  Photo by Hollis Marriott, courtesy WYNDD.

Shoshonea (Shoshonea pulvinata) in Wyoming.  It's known from sites in south central Montana also.

Limey home of Dorn's twinpod; photo by Walt Fertig, courtesy WYNDD.

In the photo above, Dorn’s twinpod (Physaria dornii) grows on gravelly slopes of Twin Creek limestone with mountain mahogany.  This twinpod is a narrow endemic limited to a few areas in central west and southwest Wyoming.  In the northern part of its range it grows on limestone soils.  Further south it does just fine on sandy-shale soils.  Are these genetically-distinct ecotypes?

Below, Cary’s beardtongue is one of the half dozen or so calciphilic endemics of the Bighorn Mountains, where there's lots of limestone and dolomite.

Penstemon caryi; photo by Andrew Kratz.

Why are we blessed with so many calciphiles?  It’s because limestone and dolomite are exposed in most mountain ranges in the state.  During much of the Paleozoic Era 570 to 245 million years ago, Wyoming was underwater.  Sand, silt and most importantly, carbonate sediments were deposited on the sea floor.  Time passed, the sediments were buried and turned to rock, and then starting about 70 million years ago, mountains were uplifted and erosion exposed outcrops of calcareous rock.

Above, simplified geologic map of Wyoming.  Purple and pale blue areas include exposures of Paleozoic limestone and dolomite.  Below, cross-section through Wyoming mountain ranges;  Paleozoic rocks are pale blue.  Click on images to view details; both are from Roberts 1989.

The map above shows the surface geology of the Bighorn Mountains in north central Wyoming.  The purple and light blue polygons include extensive exposures of limestone and dolomite.  Below, distribution of three endemic plant species reflects distribution of calcareous rock outcrops and soils.

Distribution of William's waferparsnip (Cynmopterus williamsii), Cary's beardtongue (Penstemon caryi) and Hapeman's sullivantia (Sullivantia hapemanii) in the Bighorn Mountains.  All are endemic to limestone.

Hapeman’s sullivantia (Hapemania sullivantii) is an unusual Wyoming calciphile.  It grows in moist-to-wet habitat, while most of our limestone endemics occur on dry sites.  Photo by Bonnie Heidel, courtesy WYNDD.

The limestone question pops up in many parts of the world.  It's been studied extensively in Europe, starting with botanist and plant physiologist Franz Unger.  In 1836 he published a paper contrasting the distinctive floras of limestone vs. slate regions in the Alps:  Über den Einfluß des Bodens auf die Verteilung der Gewächse (On the influence of soil on the distribution of plants).  Unger viewed the mineral composition of the rock as the main determinant of substrate-specific plant distribution, sometimes called the Chemical Soil Theory.

The Dolomites in northeastern Italy.  With so much calcareous habitat it must be a wonderful place!  Photo by Ken Driese (The Booby Hatcher), used with permission.

Dolomite bellflower (Campanula morettiana), one of many endemics in the Dolomites.
From Dolomiti Bellunisi National Park.

Cedar glade on limestone in Tennessee.  The cedars are Juniperus virginiana.  Source.

Limestone areas often are rich in endemic plant species.  For example, in the central eastern USA, cedar glades develop in areas of shallow rocky calcareous soils and exposed bedrock (above).  The flora of these glades includes 41 endemic species! (Kruckeberg 2002).

At least a dozen calciphilic plants are known to be endemic to Mount Olympus, Greece (Kruckeberg 2002).

Mytikas, highest peak of Mount Olympus (source).

The Burren in County Clare, Ireland, is one of my dream destinations.  It’s famous for its amazing flora, including many limestone-lovers.

Plants thrive in grikes (solution fissures) in limestone pavement in the Burren.  Source.

After studying the limestone question for 200 years, what have we learned?  It’s complicated!  Just look at the terminology:

basiphile vs. acidophile -- plants adapted to basic vs. acidic soils.  For a long time it was assumed that the differing pH of soils derived from calcareous rocks (slightly basic) vs. silicic rocks (slightly acidic) explained plant distributions.  It turned out to be not so simple ... in fact not even close.

calphile vs. calciphobe -- plants requiring (loving) vs. unable to grow on (fearing) calcareous substrates.  This too is an oversimplification.  Many limestone lovers will grow just fine on non-calcareous soil if there’s no competition.  Apparently in the wild they’re restricted to limestone because the competition can’t grow there.

calcicole vs. calcifuge -- plants that grow vs. do not grow in calcareous habitat in the wild.  This non-committal approach is good because for most species we have no answer to the limestone question.  But we’re not totally ignorant ... we’ve learned that plants deal with the challenges of limestone and dolomite in diverse ways.

Limestone is mainly calcium carbonate; so is dolomite, but with magnesium mixed in.  It’s not surprising then that one problem with calcareous habitat is too much calcium.  Plants need calcium but an overabundance disrupts critical processes.  Several strategies for dealing with excess calcium are known.  Some plants are able to maintain high concentrations of bound calcium in their sap without altering the concentration inside cells.  These are calciotrophic calcicoles.  There also are calciophobic calcicoles which precipitate out excess calcium and store it.  Other plants secrete calcium carbonate via glands.  The table below shows plant families in which some species are calcicoles, with strategies.

Based on information from Kinzel 1983; click on table to view.

It may be that some plants tolerate limestone with the help of microbes or mycorrhizal fungi associated with their roots.  Finally, a plant’s apparent love of limestone may have nothing to do with calcium.  White and Broadley (2003) suggest that it is “insensitivity to iron and phosphorous deficiencies that determines the flora of calcareous soils.”  And so the debate rages.

Though we're blessed with many calcicoles in Wyoming, the limestone question -- why and how they grow where they do -- has not been answered for any as far as I know.  And so we arrive back where we began -- fascinated and puzzled, and hopefully a bit wiser for the journey.

Above and below, Payson’s bladderpod on calcareous soils in the Salt River Range.  Is it a limestone lover?  a calcium addict?  a calciophobic calcicole?  We can only wonder.

Photos of Lesquerella paysonii and habitat by Hollis Marriott, courtesy WYNDD.

This post is my contribution to the December Accretionary Wedge (#63) -- Plants and Rocks (or Rocks and Plants).

Sources (in addition to links in post)

Kinzel, H.  1983.  Influence of limestone, silicates and soil pH on vegetation.  in Lange et al., eds.  Physiological plant ecology III.  Springer-Verlag.

Kruckeberg, AR.  2002.  Geology and plant life.  The effects of landforms and rock types on plants.  Seattle:  Univ. WA Press.

Roberts, S.  1989.  Wyoming geomaps.  Laramie:  Geol. Surv. WY.

White, PJ and Broadley, MR.  2003.  Calcium in plants, review article.  Ann. Bot. 92:487-511.