Evening star. [volume] (Washington, D.C.) 1854-1972, 1894-08-11

and nil the public parks the appearance
OF the city would not ne So inviting But
quite aside from the muniticence which
has made the planting and care OF the
trees possible, Washington occupies ex-
cepttonal climatic conditions. being. as IL
wer" on The border line between the north
and the south. That IS. it is far enough sout n
to permit the growth of distinctly south
ern species. such as the cypress magnolia
catalpa. coffee tree. red bud, maidenhair
tree or ginkgo of Japan, etc, and yet is
near enough 10 the northern homes Of such
as the rock maple, beech, birch. elm and
the like to permit them to grow in fun
visor. The wild plants growing in the
vicinity Of Washington exhibit the same
prOfusion OF kinds. for within a radius OF
twenty miles from the capital no less than
1.4oo varieties Of towering plants. besiaes
host of humber kinds. find their homes.
She District Of Columbia is the head and
center Of the distribution of American
Saks, for twenty-three varieties are found
Nlli here. and many other cases OF similar
profession could be pointed out.
The conditions which are now favorable
10 the growth OF great numbers of wild
Pants and the successful cultivation OF the
Ornamental shrubs and shade trees ap-
pear 10 have prevailed for vast period Of
vicinity Of Washington saw the birth. far
back in geologic time of the great group OF
plants to which nest of our modern IA
militT tres and shrubs belong. This great
group OF plants - known as the DicOtyie-
doES. plS hts having two seed leaves or
cOty ie.iOns. in the bean. squash. elm,
apple. rose. etc. 1t is the most Important
group of living plants.
The Potomac Formation.
Our knowledge of the vegetation which
81.
is derived entirely from the study Of their
fossil remains found preserved in the rocks.
We have only TO go back very short time.
ge5logicaIy speaking. before we find the
plants all unlike any now living, but i'll these
ancient plants We discern the ancestors OF
the later ones. n further step backward
and these axe replaced by others still more
ancient and unlike living plants. \ geo
logic formation exceptionally well deyel-
opel in and about the District OF Columbia.
known the Potomac formation. contains
the fossil remains OF these most ancient
dic0tyleiJns- The Potomac formation I'M
dHrhes "a good portion Of the city Of Wash
1uSJOn ami is cut through and exposed in
many Places, Is al the new reservoir. Penn
syiyania avenue extended. Connecticut ave
lie -SStsS.is d. Geological Park. Good Hope
Hin. BriSAtvCod. etc. This formation also
extends nursEwarI through Baltimore.
around -;he head OF CheSape;.ke bay, and
through New Jersey and southwark through
Virginia to upper North Carolina and Ala
bdml.
Great numbers of these ancient plants
have been dug up in and about the city,
and their stuGy has revealed many curious
things. The whole number Of varieties now
known IS not far from S'D, but of this
number only comparatively few belong to
the dicotyledOns. The parts preserved are
leaves, fruits. stems and trunks. and while
II is easy to see that they are und1ubted
dicgtyledJns. many Of them have strange,
unfamiliar and crude appearance, such as
we might expect TO find at that early day
In their history. yet crude as they are they
embrace many of the types or families Of
plants that have since become such pre-
dominant feature in our vegetation. From
this scientists are led t. believe that there
are stiH more ancient forms that have not