The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1903-04-17
OUR
n NATIVE
TREES
-. By.
THOMAS II. MACBRIDE. Phi. D.,
Professor Of Botany, IOi0d State
University.
XII.-The Geographical Story
Of Trees.
THOMAS II. MACBRIDE. Pm. D..
Professor Of Botany. Iot0d State
Ira1l..na.alIII

creeping things, some of them
probably not unlike the insig-
nificant liverworts that adorn the
damp and shady corners of our north
ern world today. We have doubtless
all observed these beautiful though less
appreciated little things, creeping, rib
bonlike structures, covering the ground
in woods or spread over the whole
moist surface of a perpendicularly
rocky wall hard by some spring or
stream. The earliest terrestrial plants,
| so far as can be guessed, were not I'M
like some OF these. We may imagine
them covering all the ground in those
! faron days, struggling constantly
among themselves for room. For
! plants, as for some other things, there
is but one direction in which room in
! creases as we go. That direction is
upward. And SO our terrestrial plants
no doubt soon learned TO push their
branches upward, the better TO secure
the light and air. But the relief is only
! temporary. Once the upward habit is
INDUCED forthwitl ensues new rivalry
! CrOwding becomes as intolerable as
before Every rising plant tries hard
to Overtop its fellows. At first the
stems lean one upon another and so re-
main erect. Anon the sitter plants
derive advantage, and those with form
ing woody tissues able to stand alone
far Outreach and overshadow all the
rest. These changes, of course, no one
has seen, but in some such way we
may assume the plants of ancient times
attained at length arboreal habit For
such accomplishments there was no
lack of time, as the geological record
shows. For ages the earth was filled
with vegetation before ever a tree or
treelike plant appeared.
In order TO appreciate properly what
| geology has to tell about the history
Of trees on the planet, it will be neces-
sary for US to understand the manner
. in which students of the oarths his
tory divide past terrestrial time. The
recorded history Of the earth, recorded
by the succession Of stratified rocks,
names several definite ages or periods
Of past time, each represented by
distinct system of the stony strata. If
we call these time divisions each by
the name of its rock system, we may
| have. beginning with the oldest, the
I In Gil
an. deyonian, carbOniferous, triassic
I iurassic. cretaceous, tertiary and re
| cent. Let this be for us simply a time
card to which we may refer what is
| known of the history Of trees 1t must
be borne in mind, however, that these
names describe periods by no means of
equal length. The first three or four
represent perhaps greater length Of
time than all the rest put together
Any one Of them, however, is far
| enough away from us in time, for
the duration Of these geologic periods
was vast beyond all human computa-
ton. Now. the oldest arborea plants
come TO us from the devonian. Very
/ curious looking trees they must have
been. having little resemblance to any
OF our modern forms save in the fact
that they had woody tissues and stood
erect. Some Of them were fifty or
/ hundred feet high and had q diameter
of one to three feet at the ground. But
they were nevertheless untreelike
They had no twigs, no leafy branches,
10 flowers no seeds. They were in
stead covered all over with leaves
scalelike leaves. There were branches
not many, and these were covered, too
with leaves. The Chill pine, for all its
scales, it's green leafy cone as well,
! bears seeds. Our earliest tree, this
devonian forerunner Of all the forests
had no seeds. 1t was reproduced by
spores. and these in development were
conditioned as described, depended
upon water for the mating of the cells
/ In fact, the Oldest trees of earth were
not unlike overgrown BrObdingnag
/ types Of the little ground pine or club
I llOSS W hltl Ntl pcLS lllt NDoNidlluS u
Canada and spreads beneath our mod
| ern trees over all the eastern states
! If we could imagine in the case of our
eastern forest all the trees of present
+ type removed and the ground given up
to club mosscs, and if we could then
fancy these towering like leaf col
/ umns with yellow spikes Of spores far
above our heads. we might so form
some conception of the earliest tree
that has left of itself a record on the
earth. There was, however, after ALL
some variety.
BY no means all alike were those old
forest trees. The number Of types then
extant was not great indeed, but every
type terrestrial took on aboreal form.
In devonian times even our securing
rushes or joint rushes seem TO have
played the role Of trees, and so with
many Of the ferns. The very first for
est was a spore bearing forest. The
trees were big enough and plenty