Sunday, June 28, 2015

Paying Attention

Nature will bear the closest inspection.  She invites us to lay our eye level with her smallest leaf, and take an insect view of its plain.      Henry David Thoreau

I took a field botany (plant identification) course back in about 1980 at the University of Rhode Island with the famous Elmer Palmatier.  I stumbled along with a couple dozen others behind the Master (who, as always, wore his jacket and tie), struggling to collect plant specimens and absorb his comments before we were left behind.  We would return from our little field trips with about twenty five new specimens to dry to mount to make identification flashcards.  (Thirty-five years later those plant cards are still in occasional use.)  Then we would have to memorize these plants--common name, Latin name, and family--before the next quiz.  On Saturdays professor Palmatier would lead plant hikes for anyone interested.  By summer's end, I could (sort of) identify almost three hundred plant species by sight.  I was pretty pleased with myself, and that pleasure has not entirely abated--though I've forgotten most of them by now.

Lately, though, as I've paid close and regular attention to a handful of species, I've learned much more.  Most of it is undoubtedly available on the internet, and I haven't been shy about consulting web resources, but I've benefited most from simple hands-on observation of real plants. 

What has acquaintanceship with trees brought me?

Basswood (Tilia americana) has flowers with all typical flower parts, both  male and female.

Flowering dogwood (Cornus florida) had small flowers
clustered tightly, but four large bracts around the flower cluster
fool people into thinking the whole cluster is just one large flower.

Grass flowers have an intricate, delicate beauty--even with no petals--
but you need to look closely to appreciate them.  Orchard grass (Dactylis glomerata),
panic grass (Panicum virgatum), and big bluestem (Andropogon gerardii).

I've become familiar with the flowers and fruits of many species.  In the spring of last year I waited for trees to flower, but was not always sure what I would see.  Some trees showed no flowers I could see, but produced fruit later.  Others produced nothing.  In particular, the long, swinging, male catkins of oaks color the whole tree tan in spring, but there are no apparent female flowers.  Observing fallen twigs, I discovered that female flowers are shy, retiring things borne singly or in pairs in the leaf axils.  Even after flowering, they still bear the two tiny, curving stigmas that accepted the wind-blown pollen of another tree.  What's more, they take two seasons to mature in red and black oaks, and you can find the larger, older acorns on last year's twigs.

Flowering male catkins of black oak (Quercus velutina);
tiny, bud-like, reddish first-year, and larger second-year acorns.

I've learned that even closely-related trees can vary a lot: red maples are male or female, but silver maple trees have both male and female flowers.  Norway maples trees have male and female flowers, and also flowers will both male and female parts, AND alone of the local maples are pollinated by insects, rather than wind.

Female silver maple (Acer sacharinum) flowers

 Male and female red maple (Acer rubrum) flowers.

Unisexual and bisexual flowers of Norway maple (Acer platanoides).

I've caught on to patterns, and to differences in patterns, and become curious:

How does Norway maple come to be insect pollinated, when the other four maples I know are all wind pollinated?  They are very different strategies: insects must be attracted, and the pollen is usually stickier, while wind-blown pollen must be loose so the wind can carry individual grains.

While the other maples drop their samaras gradually over a period of weeks, how is it that red maple drops theirs almost all at once?  Since the seeds are dispersed by wind, it would seem wiser to drop them gradually, in hopes that at least some of the kids would catch a favorable wind.

 Red maple samaras: here today, gone tomorrow.

How can it be adaptive for red and black oaks to take a year-and-a-half to mature their acorns, while white oak does the job in less than one?  A two-year maturation seems riskier to me.

How is it that I could find almost no neighborhood white pine with cones last year, but all those same trees are laden with cones this year? (Yet walking up Great Blue Hill, only ten miles away, revealed  almost none this year.)  Is it rainfall at a critical period?  Temperature?  Wind to carry the pollen?  What??

It's going to be a good year for white pine (Pinus strobus) reproduction.

How is it that red maple, which has its pairs of buds spaced only an inch or so apart--all of which break every spring to produce shoots--end up making such widely-spaced branches?

Tiny "spur branches" may grow only a fraction of an inch each year.
Few will grow into full-sized branches on this red maple.

(I've begun to answer this last: though all buds produce shoots, most of the side buds--instead of growing long shoots the way the end buds do--become very short, small "spur branches" that have leaves packed close together but seldom grow into full-sized branches.) 

I've had to revise my "knowledge"so often that I've learned a good deal of humility along the way.  At the same time that I know more, I'm simply not as sure of myself as once I was.  Part of that, of course, is being reminded of how much I don't know, because I never before thought to ask the questions I do now.

My oldest son is very fond of computer games, and was regaling me a few days ago with news of the new "world" of an internet game: it would have bazillions of stars and planets to explore and gazillions of places on those worlds, so that it would take a single player many lifetimes to explore them all.  

I inquired gently how such places were created.  It seems that some come from the imaginations of game designers, and probably most are computer-generated following some sort of algorithms.  I wondered aloud what the value of exploring someone else's (or something else's) imagined world.  I wondered whether this world had much basis in reality; for example, mountains on earth are usually where they are for reasons of plate tectonics, and their details are matters of rock types and structure, time and climate.  I wondered what the game designers knew about these things.  I concluded that, for my part, I would much rather explore the real thing: actual physical places and things that had evolved over thousands of millions of years of history.  I'm not sure if I got through to him, though.  High definition graphics, explosions, death and destruction are pretty powerful attractions.

The blade of grass you tread on this morning--no less than the greatest redwood--has become fitted by natural selection over millenia to be adapted to a place in the economy of nature.*  That place is a cooperative venture of the species with which it interacts, and a geology evolved over thousands of millenia.  That blade of grass powers its life with light from a medium-sized, middle-aged star a hundred million kilometers away that has blazed for four-and-a-half billion years. 

Computer games?  I still prefer the real.

Our inventions are wont to be pretty toys, which distract our attention from serious things. They are but improved means to an unimproved end.    
Henry David Thoreau, Walden

*"Niche" is the more modern expression, but Darwin spoke of "the economy of nature," an evocative term which I love.

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