Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1903-02-03
THOMAS H. MACBRIDE. Pm. ~,
Professor of Botany, IotDd State
University.

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 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 earth's 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 a
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
archean, laurentian, cambrian, siluri'
an, devonian, carboniferous. triassic,
jurassic, cretaceous, tertiary and re-
cent. Let this be for us simply 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 compute
ton. Now, the oldest arboreal 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 q
hundred feet high and had diameter
Of one to three feet at the ground. But
they were nevertheless untreelike
They had no twigs, no leafy branches
no 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 oil its
scales, Its 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
moss which carpets the woodlands OF
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 MOSES, 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 record on the
earth. There was. however, after all,
some variety.
BY no means all alike were those ole
forest trees. The number Of types ther
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
enough. but a lumberman might think
them of little value after all. They
were either hollow or else had enor'
nous pith. so that the amount Of wood
even In the largest specimen was com
paratively small. Nevertheless thest
old ,es did have value. These forest!
lived OH to cover the earth in the subse
Qucnt carboniferous time, in the age Of
coal, and no doubt contributed theil
share of organic material, Of leaves ant
bark and spores and wood, to form vas
beds Of fuel that, as we know, make
possible the wealth and convenience Of
the present.
But the devonian has something bet
ter than club MOSES and ferns to show
us, even II these did assume the size
Of trees. Bigness Is not always syno
nym for excellence. From rocks OF
different parts Of the northern hem.
isphere, rocks belonging to the middle
devonian, we have fossil coniferous
wood, specimens representing the mod.
ern cone bearers-larches, spruces, yews
and pines. All the trees referred to-
the spore bearing trees, seem to have
been confined to marshes and the damp
shores of lakes or lagoons. But the
struggle for existence. and especially,
as we suppose, the disadvantage of ter
restrial fertilization, at length drove
some of these arboreous forms to high
or ground and different habits. The
minated spores no longer fell to earth
for mere fortuitous union, but In the
fruit itself upon the trees the mating
Of the cells took place, and we have
suddenly a real forest Of coniferous