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FOREWORD
My love of plants, trees especially, traces back to my early
childhood when my father gave me a small collection of tree leaves scotch-taped
to the pages of a notebook. My father, an ardent plant enthusiast, kept an
experimental apple orchard as an avocation, and was interested not only in
botany and horticulture, but in all aspects of the natural world. When I
was just nine years old he sadly lost his life to cancer while in the prime
of his life, and I regret he was never to see his son, inspired by his small
gift, grow to share his passion with the plant world. While my father provided
the spark, my mother supplied the fuel for my appreciation of natural history,
with her unflagging support and encouragement in all my endeavors, botany
included.
Equipped with an assortment of field guides, I spent much of my youth stalking
the trees and shrubs that grew in nearby woods, gardens, and yards in my
native upstate New York. The number of woody plants hardy enough to survive
the region's harsh winters are limited, so I soon broadened my scope to the
entire cornucopia of organisms that compose the vast and eclectic plant kingdom.
Every tree, shrub, forb, grass, fungi, fern, moss, sedge, rush, lichen, etc.,
was subject to my scrutiny. Much like genealogists search for the identity
of their ancestors, I thumbed through botany floras and field guides searching
for the identity of an inscrutable specimen until finally,
aha!—Toxicodendron vernix—Poison Sumac!
Plant identification was often an exercise in mystery-solving with a minimum
of clues. A flower bud, a leaf, an acorn, or perhaps the unique branching
architecture of a tree against a wintry backdrop often would be information
enough to identify a specimen. Other times it was necessary to wait until
the plant came into flower before identification was possible. Dichotomous
keys in floras and manuals were an indispensable tool. Once I ascertained
the plant's common name, I would look up its Latin binomial scientific name,
and add to my understanding of botanical nomenclature. Like people, plants
have a first name—the species name, and a last name—the genus name.
The Swedish botanist Carl Linnaeus came up with the binomial system of naming
plants in the mid-1700s, and though the system is centuries old, there are
currently efforts among certain taxonomic specialists to modify the Linnaean
system. Plant classification is never in stasis.
Discovering new plants and learning more about them was an interesting hobby
inasmuch I learned to familiarize myself with the flora of my surroundings,
but when I began to look deeper into how plants were related to one another
and their environment—where exactly a plant lay in the grand scheme
of things—matters grew more complicated, profoundly more complicated.
Botanists and taxonomists pigeonhole plants into categories within a vast
taxonomic hierarchy of progressively larger and more broadly defined groups:
species, genera, families, orders, classes, divisions, and kingdoms. And
each of these ranks can be broken down into sub-ranks, and sub-sub-ranks.
Just how plants are ranked into hierarchal structures characterizes
those who do the ranking as either "lumpers," or "splitters," and this can
lead to much ambiguity. But as I plunged deeper into systematics, I found
the knotty concept of hiercharchy of ranks was just one of an array of
complications in plant systematics, and I would soon discover that my transition
from basic plant Identification, to plant systematics, was becoming a foray
into the arcane—perhaps even the sublime.
Defined as the study of biological diversity and the relationships among
organisms, systematics (essentially synonymous with taxonomy) attempts to
understand the evolutionary interrelationships of living things, and to interpret
the way in which life has diversified and changed over time. It is central
to biology. To explore the history of systematics is to revisit some of the
great scientific and philosophical debates of history. Taxonomists in the
past broadly modeled their classification schemes on the ideas of such great
thinkers as Aristotle, Descartes, Linnaeus T. H. Huxley, Lamarck, and Darwin.
As with most other scientific disciplines, taxonomy has had a long history
of gradual progression through a steady accumulation of knowledge punctuated
by paradigm shifts inspired by the revolutionary thinking of Descartes, Linnaeus,
Lamarck, Bessey, and most notably, Darwin. In the wake of these upheavals,
newly enlightened taxonomists have had to scramble to mend the older, outdated
systems.
Twenty years ago I shifted my emphasis away from botany to science in general.
At that time, the classification system used by most botanists was the
Engler and Prantl system, a system still in use in many botany manuals
and floras today. Having been in widespread use for decades, I viewed the
system as a sort of a rigid, immutable status quo, inviolable to updating
or revision. But when I returned to botanical taxonomy three years ago, my
cozy familiarization with the age-old Engler and Prantl scheme was shattered.
Another major paradigm shift in taxonomy was going on in my absence. Engler
and Prantl was being up heaved and upended—by the new phylogenetic paradigm.
While this phylogenetic classification system had been around for quite some
time, only recently has it begun to play catch-up. In the past twenty years,
taxonomy has been thoroughly transformed.
The lesson here is the science of taxonomy, and indeed, science in general,
is no more resistant to change than the very subjects it attempts to
classify—a three billion-year legacy of continuously changing organisms
in a long line of descent from the progenitor of the single-celled
bacteria—to the unfathomably complex creatures we call human beings.
The passage of randomly varying genetic information from parent to offspring,
each generation modified by non-random selective forces in nature—this,
simply, is phylogenics—and it's pure Darwinian. We are all connected
by a vast phylogenetic tree of life. A wondrous notion indeed.
Present-day taxonomy is as exciting and dynamic as ever. New molecular analyses
of plant DNA, as well as traditional methods of establishing phylogenetic
relationships, continue to fit the pieces into the great evolutionary puzzle.
The works of Cronquist, Thorne, Takhtajan, Dahlgren, and Reveal, and a host
of other systematists have made major contributions in plant phylogenetic
taxonomy. Grouping organisms into logical, coherent ranks in accordance with
their evolutionary lineages is a complex endeavor subject to much latitude
in interpretation, thus giving rise to a wide range of divergent views by
taxonomists. Nonetheless, they all share a common goal: to gather life's
verdant hodge-podge of twigs and branches scattered about the planet Earth
and carefully assemble them into a grand Tree of Life.
Flower in the crannied wall
I pluck you out of crannies
I hold you here, root and all, in my hand,
Little flower—but if I could understand
What you are, root and all, and all in all,
I should know what God and man is.
—Alfred Lord Tennyson, in
"Flower in the crannied wall"
On to the
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