12

BULLETIN 205.

LINDEN.

The linden requires an abundance of deep rich soil and suffers much from
gas, from drought, and from insect attacks. It does fairly well in Wash-
ington, but is little planted now because of the extra care it requires as
regards soil and water. In Berlin, Frankfurt, Hamburg, and Paris, the
leaves of most varieties of linden fall prematurely on account of insect and
fungus attacks. In Philadelphia a few years ago all the large lindens were
killed by borers. A further objection to this tree is the litter made by its
blossoms and fruit.

TULIP-TREE.

The tulip-tree is too large except for the widest avenues and park borders,
where there is a quantity of rich deep soil and abundance of room. It is
likewise difficult to transplant, the branches are very brittle, and the leaves
are continually dropping throughout the season. It is, however, prac-
tically free from enemies.

BLACK LOCUST.

The black locust is a rapid grower, hardy, easily propagated and trans-
planted, and does well in poor soil.
It is successfully cultivated in
Paris, where the top is kept small
and spherical and the branches
thickly clustered. Its hard and
durable wood is beginning to be
used in Paris for paving the streets.
On the other hand, the tree is
scraggly and angular in form, its
branches brittle, its foliage short-
lived, its pods unsightly, and its
roots badly given to sprouting.
The locust borer often kills the
black locust, as well as the honey
locust, and has been known to

FIG. 17. — Black locusts near Per e
Le Chaise, Paris.

spread from these trees to certain species of oaks.

WILLOW.

The weeping willow is the only
species used on streets, and its
occurrence is rare. It grows
rapidly and when perfect makes a
fine appearance, but the wood is
tender and is often attacked by
fnngi, while the tussock moth and
other leaf-eating insects frequently
destroy its foliage. The white
willow is excellent for windbreaks
and for planting along the banks
of streams, railroads, and other
embankments. Fine rows of this

FIG. ^.—Old while willows along
Cascadilla Creek, Ithaca, planted
to preserve the banks of the stream.

PLATE II— THE PROTECTION OF SHADE TREES.

-

NEW YORK FORESTRY PAMPHLETS
VOL. Ill

Tree Study -- John Bentley,' Jr. , Cornell Univ.

How the Trees Look in Winter — L. H. Bailey,

College of Agriculture, Cornell University,
1899.

Evergreens, and How They Shed Their Leaves —
H. P. Gould, College of Agriculture, Cor-
nell University, 1899,

The Cultivated Poplars — Bull. 68 -- L. H. Bai-
ley, Cornell Agri. Experiment Station, 1894.

Shade Trees — Bulletin 205 — W. A. Mur rill--
Cornell Agri. Experiment Station.

Studies of Some Shade Tree and Timber Destroying
Fungi — Geo. F. Atkinson ~ Bulletin 193,
Cornell Agri. Experiment Station. T-C

Blister Rust of Pines and the European Currant
Rust — Geo. G. Atwood, Hew York State
Department of Agriculture. Horticultural
Bulletin No. 2.

Damping Off — Bulletin 94, Cornell Agri. Experi-
ment Station — Oeo. F. Atkinson.

Control of Two Elm-Tree Pests — Glenn W. Herrick
Cornell Agri. Experiment Station.

The Bronze Birch Borer — M. V. Slingerland —
Bulletin 234 — Cornell Agri. Experiment
Station.

The Larch Case-Bearer — Glenn W. Herrick —
Bulletin 322 — Cornell Agri. Experiment
Station.

The Snow-White Linden Moth — Glenn W. Herrick ~
Bulletin 286 — Cornell Agri. Experiment
Station.

The Elm Leaf-Beetle ~ Glenn W.- Herrick, Circular
Ho, 8 — Cornell Agri. Experiment Station V

Hints on Rural School Grounds p-- fr.^R. Bailey —
Bull. 160, Cornell Agri. Experiment Station.

Mushrooms: II ~ Geo. F. Atkinson — Bull. 168,
Cornell Agri. Experiment Station.

n8

TREE STUDY

" Peace of the forest, rich, profound,
Gather me closely, fold me round;
Grant that the trivial care and strife,
The petty motive, the jarring sound,
Melt and merge in your lovelier life.
The myriad whispers of grass and pine,
The stir of wings in the quest divine,
I claim their music and make it mine.11

ELIZABETH R. MACDONALD

THE ELM
JOHN BENTLEY, JR.

Of the many trees that are common in New York State, the elm is
doubtless the most familiar to boys and girls. The reason for this is plain,
when we consider that the elm is a tree of the farms, the home lawns, and
the streets of the towns, rather than a tree of the deep woods. While it
is found occasionally in the forest, it is almost always scattered among
other trees and never forms a large proportion of the forest, as do maples,
birches, pines, or oaks. Throughout the New England States, New York,
and Pennsylvania, the elm is one of the commonest shade trees, not only
for the streets of the towns and villages but also for the grounds about
the home. The tree is so graceful and beautiful, and, when old, so stately
and dignified, that it well deserves the place which it holds in the esti-
mation of the people.

The elm has a very distinctive form and habit of growth. Other trees
seen from a distance are not always easy to recognize: the maple and
the beech look somewhat alike, especially when young; the oak and the
chestnut, the ash and the hickory, resemble one another slightly. But
the elm, with its massive trunk — which quickly breaks up into several
large branches, giving the tree an urn-shaped appearance — and the
delicacy of the twigs and branchlets, forming a crown with a fringe-like
margin, is easy to recognize even at some little distance. To a remark-
able degree it combines strength with grace and beauty.

The elm is a widely distributed tree. It is found in southern New-
foundland and through the southern part of Canada as far west as the
northern shore of Lake Superior. It grows along the Atlantic coast
as far south as Florida, although it never reaches very large size in the
southern part of its range. Westward it is found from South Dakota
to Texas, although not in such large numbers as in the East. Everywhere
it shows a preference for the low, rich lands that border rivers and streams,
and it grows to its largest size where the soil is rich, fertile, deep, and
moist. Under favorable conditions it will grow to a height of one hun-
dred and twenty feet and a diameter of eleven feet. Many very large
trees have become famous, as the large elm at Lancaster, Massachusetts,
and the two elms on the river bank at Wilkes-Barre, Pennsylvania. It
is the wide spread of the branches, as well as the massive size of the trunk,
which makes the elm impressive ; sometimes the crown of a tree measures
one hundred and twenty feet across.

The elm tree, large as it is, springs from a very small seed. The flowers,
which are inconspicuous, blossom early, before the leaves are fully grown,
fade soon after, and are as quickly followed by the ripening seeds. These
small seeds have wings on the margins, with sharp points, and are very

120

short-lived. Unless they fall on soil that makes a good seed bed and
germinate immediately, they will die. They cannot wait, as do the seeds
of the hickory, pine, and many other familiar trees. (Can you think
of another familiar tree that ripens its seeds in early summer? See the
Rural School Leaflet for September, 1912, page 163.) Besides plenty
of moisture, which is one thing that the little elm seedling must have
at the start, the quality of the soil and the amount of light that comes
to che seedling have great influence on its growth. The soil must be
rich and mellow, so that the rootlets can penetrate easily and find plenty
of food material, and there must be plenty of light, so that the seedling
can grow rapidly and become able to take care of itself before the autumn

frosts arrive. This demand for
light is one reason why we do
not find elm trees in the deep,
dark woods. When we do find
an elm in the forest, it is be-
cause there was an opening in
which the little seedling could
get a start. Elms will not do
well when they are overtopped
by their neighbors.

When standing where there
is plenty of room and light,
the elm tree grows rather
rapidly. Many men who do
not consider themselves old can
remember the time when, as
boys, they watched their fathers set out elm trees along the roads or
on the lawn, and those trees have now grown to be of large size. But
the largest elms — those that are one hundred feet high and six to ten
feet in diameter, with the large, spreading crowns — are probably two
hundred years old or even older.

Whether the elm is more beautiful in summer or in winter it is difficult
to say. In summer its dense foliage hangs in graceful sprays from the
drooping branchlets at the ends of the long limbs, swaying in the breeze
and making a delightful shade. The upper side of the leaf is dark green;
the under side is grayish green, reflecting a soft light which is very
pleasant. Stripped of its foliage the elm presents an appearance in
winter which shows its strength — not the rugged strength of the oak,
with its gnarled, irregular branches, but a supple strength suggestive
of self-contained reserve force. It is in the winter, too, that the delicacy
of the smaller branches is seen to best advantage. Every wind sways

Leaf and fruit of American elm

121

American elm in winter

122

them but they do not break; they yield gracefully and seem to enjoy
the blasts of winter.

Unfortunately the elm is the prey of a tiny insect, which eats the leaves
and threatens to destroy the tree entirely in some parts of the country.
This little insect, known as the elm leaf-beetle, has damaged thousands
and thousands of elm trees during the past few years ; and although many
persons have worked hard to get rid of it, the pest is continually spreading.
The shade trees in towns and cities suffer most, apparently, and it is
necessary to act promptly if the elm trees are to be saved. The insect
itself is only about one quarter of an inch in length, brownish yellow
in color, marked with a dark line along each side of its back. It sleeps
during the winter, and the same warm days that bring out the elm leaves
awaken this enemy of the elms. The beetles fly to the trees and begin
to feed by eating small holes in the leaves. In a very few days the eggs
are laid, and these quickly hatch into little grubs which begin in earnest
to eat the leaves. So many eggs are laid that the number of grubs at
work on the leaves is enormous. In fifteen or twenty days the grubs
have completed their growth, and, unfortunately, their work of destruction
also. They now crawl down the tree, and by the time another ten days
have passed they emerge as fully grown beetles and are ready to repeat
the process. Sometimes there are two complete broods of the insects
in a single season, but the last brood as a rule does less damage than the
first.

The only way to save the elms from this enemy is to spray the leaves
with a poisonous liquid. Although it costs twenty-five to sixty cents
to have a tree sprayed, it will be necessary to spray our elm trees sys-
tematically if we wish to save them. Those who are interested in the
work of saving the elms should write to the State College of Agricul-
ture and ask for a copy of Professor Herrick's Experiment Station Cir-
cular No. 8, entitled " The Elm Leaf-Beetle."

The next time you are in the woods, see whether you can find any
elm trees growing where the woods are thick. If you see any, notice
the shape of their trunks and their crowns. Compare them with the
trees that grow along the streets in town. What do you think makes
this difference in form? Again, if you find any elm trees in the woods,
notice the kind of soil in which they grow best. Is it wet or dry? What
other kinds of trees are found growing with the elm?

About the last of May or the first of June, watch the elm to see when
the seeds begin to fall. Take a few of them and sow them in a garden
bed where the soil is soft, rich, and moist. Perhaps you will be able
to see the small seedlings grow to a size that will enable them to take
care of themselves before winter sets in.

I23

The wood of the elm is useful for purposes demanding great toughness.
It is often used in the making of barrels and fruit baskets. It is hard
to split and work, and for that reason carpenters do not use it for wood-
work or finishing; but if a tough wood is needed, a better wood than
that of the elm is difficult to find.

THE PINES OF NEW YORK
JOHN BENTLEY, JR.

In the winter months, when most of our forest trees are leafless, the
firs, spruces, and pines, with their dark green foliage, are a cheerful sight.
It makes us feel, somehow,
that after all the woods
are not lifeless in winter,
and that there are some
trees bold and hardy
enough to withstand the
snow and the cold. Pines
are particularly notice-
able, because there is
more motion and life in
their foliage than in -the
stiff, rigid foliage of
spruces and firs. Then,
too, pines are more
familiar to most of the
boys and girls in the
State, because spruces
and firs belong to the
cold climate of the
mountains.

There are five pines
that are native to New
York State, besides
several others that may White Pine

be found occasionally in our parks. The five native trees are (i) the
white pine, (2) the pitch pine, (3) the red, or Norway, pine, (4) the
jack pine, and (5) the Jersey scrub pine. The last two are not very
common, however, and most of us will find only the three first
mentioned.

The pines as a group are marked by three characteristics which all
boys and girls should notice first of all. They are: (i) the needle-shaped

. 124

leaves, borne in clusters of two, three, or five needles; (2) the cones, in
which the little seeds are borne; and (3) the wood, which always contains
more or less pitch, or resin. These characters distinguish the coniferous
(cone-bearing) trees from the broad-leaved trees. The term " evergreen "
should not be applied to the pines, spruces, and firs, because there are
other trees, as the holly and the live oak, which retain their leaves through-
out the winter and are just as truly evergreen as is the pine or the spruce.
Then, again, there is the larch, about which we learned last year
(Rural School Leaflet for September, 1912, page 160), which
bears cones and yet sheds its leaves every year. The leaves of
the larch are needle-shaped, it bears cones, and there is some resin
in the wood, and therefore it clearly belongs to the same family as
do pines, firs, spruces, and hemlocks. In order to avoid all
confusion, therefore, I would suggest that we learn to call all
cone-bearing trees " conifers," which means " cone-bearers."
Then let us call the others "broadleaf trees"; this will properly
include the live oaks and the holly, and will do away with the
confusing term " deciduous " (leaf -shedding) trees. Another
term that is frequently heard is " hardwoods." As generally
used, this term means the broadleaf trees, although there are
some conifers with very hard wood — yellow pine, for example —
and some " hardwoods," or " broadleaf "" trees, with very soft
wood, such as the poplar and the willow. The use of confusing
terms should be abandoned and the terms " conifer " and
"broadleaf," while sounding a little strange at first, will express
our meaning more nearly.

The pines are nearly all of great value because of their wood,
which is strong for its weight, straight-grained, and easily

needle worked — that is, carpenters have little difficulty in planing and
cluster •••:'•. ,/ • o t '4.1*

shaping it to their purposes. Some of the pines have very

hard, heavy, resinous wood, as the southern yellow pine; but our
northern white pine is light and soft and contains only a moderate
amount of resin. The white pine was formerly the most important
timber tree of all the northeastern States, and many millions of board
feet of white pine have been cut from the forests of New York State
within the past century. It is still considered a very valuable tree, and
lumbermen are always glad when they can find any white pine to cut
because they know that it will bring a good price in the markets.

The white pine is a tall, straight-trunked tree, often reaching a height
of one hundred and twenty-five feet in the dense forests of the Adirondack
Mountains. When growing in the woods the trunk is frequently clear
of all branches for sixty or seventy feet, but when grown in the open,

125

where it has plenty of room, the crown is broad, with many limbs growing
to within fifteen or twenty feet of the ground, and under these conditions
the tree never grows very tall.. The lumberman likes best
of all the tall, straight trees of the forests, for these
will yield fine, straight-grained lumber with few knots.

The white pine can be distinguished from the other
pines of this State by the needles, which grow in clusters
of five. Examine the foliage of a pine tree; you will see
that the needles, instead of growing singly, grow in
bunches, or clusters. In the white pine there are always
five needles in a cluster. The individual needles are two
and one half to five inches long, slender, flexible, bluish
green, with a fine white streak. Let us now look for some
cones. We may find some growing on the tree, or we can
examine those that have fallen from the tree and are
now lying on the ground. The white pine cone is about
five inches in length, is usually slightly curved, and is
slender, rarely exceeding an inch in thickness. Let us
look a little more closely and see whether there are any

ten pine needle • • -, ,

cluster spines, or prickles, on

the cone. If we have
)icked up a dry cone the seeds have
loubtless been shed and scattered,
f we can find a fresh cone with
eeds in it, we can see how each seed
3 provided with a thin wing, which
nables the wind to blow it for long
listances.

Now let us consider the pitch pine,

/hich is probably the next most com-

lon pine tree of this State. It is

enerally found growing on very poor

oils, where only the hardiest trees

r shrubs will thrive. This tree can

row in these poor situations because

f its thick bark (often two inches

lick at the base of the tree) and

I Because it can resist fire much better

•jlian can the white pine. It is not

l| early so neat in appearance as the

fttiiM*.

'Pitch pine

]• hite pine; its branches are irregular, the trunk is not so tall and
Straight, and the old cones frequently hang on the tree for years. The

126

foliage is stiff and the needles are borne in clusters of three \ this at once
distinguishes it from the white pine. The needles are a dark yellow-
green instead of a blue-green. The cones are short and stout, about two
or three inches long and two inches thick, and the cone-scales are armed
with prickles. There is not the slightest resemblance between the white
pine and the pitch pine, either in the needles, cones, or bark; and if you
have an opportunity to look at the wood after the tree has been cut,
you will find that there is no more resemblance there. The wood of
the pitch pine is coarse-grained, full of pitch, and not adapted to the
fine work for which white pine is used. Indeed, the wood of pitch pine
is of little value except for coarse, rough lumber and for excelsior.

The red pine, or Norway pine, as it is frequently called, is a tree that
is not found in many parts of this State. It is common only in the
Adirondack region, where it grows on light, sandy soils and has plenty
of sunlight. It may be found occasionally, however, in other parts of
northern New York. It can be distinguished by its long, flexible needles
(four to six inches long), which are borne two in a cluster. The cones
are two to two and one half inches long and have no prickles. Taking
the cones and the needles together, there is no danger of confusing this
tree with the other two pines mentioned.

The red pine reaches a height of seventy-five or eighty feet. The wood
is harder than that of the white pine, yet, like white pine, it is not durable
in contact with the soil. Because of its hardness it is not so valuable a
timber as white pine, but the red pine possesses the great advantage of
being a tree that will grow well on land too poor to produce a satisfactory
crop of white pine. It rarely makes close forests, because it is a tree
that demands a great amount of light for its growth. Red pine trees are
never found in large numbers together, at least in this State, but are found
mixed with other trees, especially at the edge of lakes or in openings
throughout the sandy stretches of country that are common in the
Adirondack Mountains.

The jack, or scrub, pine is not frequently seen in this State except in
dry, sandy, barren soils in the northern part. It is usually a small, scrubby
tree, with irregular branches, and of such poor form that it is practically
worthless for lumber. The leaves are bluish green, covered with a gray
bloom, and about two inches in length. They are borne in clusters of
two, are twisted, and have a tendency to spread apart. The cones are
small (rarely more than two inches long) and are armed with small
prickles, which, however, may drop off.

The Jersey scrub pine is still more irregular and worthless as a lumber-
producing tree. It grows in poor, sandy soil and is found growing wild
only on Long Island. The needles are borne in clusters of two and the
cones have prickles.

127

THE MAPLES OF NEW YORK
JOHN BENTLEY, JR.

The maple family is a large one, containing many trees that are not
only useful but also ornamental. In fact, most of the maples are valued
chiefly because of their beauty of foliage. About thirteen kinds are con-

sidered native to
but by far the
of the maples are
and the islands
continent. Many
maples — some of
some shrubs —
in this country
in parks and gar-
streets; so that,
in the country or
are almost sure
Maples are
perhaps, because
Whether we con-
ual leaves of a
the whole mass
appears on a large
leaves are beauti-
tender leaves of
maple when they

the United States,
greatest number
native to Asia
bordering that
of these foreign
them trees, and
have been planted
and are common
dens or along city
whether we are
in the city, we
to see maple trees,
noticeable chiefly,
of their foliage,
sider the individ-
silver maple or
of foliage as it
sugar maple, the
ful. The little
the soft, or red,
burst from the

Sugar maple

buds in April are rich and warm in coloring; and what boy or girl who
has been in the country during the month of October does not know
the brilliant colors for which the maples are famous? The reds, golds,
and yellows seem to flood the autumn air with a warmth and light which
adds life to it.

Let us make a list of the maples that we may expect to find in New
York State, and then add a few descriptive notes regarding them:

1. Sugar, or hard, maple

2. Red, or soft, maple

3. Moosewood, or striped maple (a shrub or small tree)

4. Mountain maple (a shrub)

5. Silver maple

6. Box elder, or ash-leaved maple

7. Norway maple (not native, but commonly planted)
Sycamore maple (imported)

128

Sugar maple

Red maple Norway maple

Outline drawings for blackboard work

Moosewood maple Sycamore maple

Outline drawings for blackboard work

130

The sugar maple is the largest and finest of the family. In deep woods,
where it grows with the beech, birch, basswood, hemlock, ash, and other
trees, it often reaches a height of more than one hundred feet, and has
a trunk perhaps four feet in diameter which rises straight and full without
a limb for more than half the height of the tree. Such a tree is in great
contrast to those growing along the roadside, which are shorter and large-
crowned and which have so many branches that it is difficult to find any
one stem that seems to be the leader. Why does the maple tree growing
in the open, where it has plenty of room, form such a round-headed crown,
with no well-defined leader? Study the method of branching and see
whether you can find out.

The red maple can be distinguished from the sugar maple by its leaves
in summer and by its buds in winter. The two kinds are contrasted in
the drawings. Note that the lobes of the leaves (of which three are usually
very conspicuous) are separated by U-shaped depressions, or sinuses,
in the case of the sugar maple, and by V-shaped sinuses in the red maple.
The buds of the sugar maple are long, pointed, and of a brown color,
while those of the red maple are shorter, rounded, and red in color. These
marks will serve as a means of identification at any time of the year.
The red maple prefers a wet, swampy soil, while the hard maple thrives
in a rich, cool, well-drained soil.

The silver maple has a very beautiful leaf, by which it can always be
recognized in summer. Notice, in the drawing, how deeply and finely
the leaves are cut; this gives to the tree its peculiar delicacy and makes
it desirable for decorative purposes. In fact, the tree is of little use
except as an ornament ; the wood is soft, weak, and brittle when compared
with that of the sugar maple.

The mountain maple and the moosewood (or striped maple) are very
humble members of the maple family, rarely growing to be more than
shrubs ; but they add greatly to the beauty of the woods as we know them
in the North. Both these maples are common in the woods of New York,
especially in the Catskills, the Adirondacks, and other hilly parts of the
State. Favorite situations for these maples are steep, rocky slopes,
where there is plenty of moisture, as on the north side of hills or mountains.
The leaves are much like the leaves of other maple trees; those of the
mountain maple resemble those of the red maple, but the little veins
on the former are much more noticeable and the underside of the leaf
is covered with a whitish down, which is absent from the red maple.
Another character that will serve to distinguish this little maple from
the red maple is the seed. The flowers of the mountain maple appear
in clusters, which botanists call "racemes"; that is, there are several
flowers borne on a central axis and they begin to blossom at the bottom

first. The artist has come to our assistance again, and you will see in
the drawing of the seeds that the difference in the fruit is clearly brought
out. The red maple bears its seeds in clusters close to the stem.

The moosewood has a leaf that distinguishes it easily from other maples.
The leaf is large, with lobes only slightly cut, and is soft in texture.
Perhaps the most noticeable character of this tree — one by which the
boys will learn to recognize it — is the bark. This is reddish or greenish
brown marked with pale stripes running up and down, so that the name
" striped maple " is very appropriate. The flowers of this maple also
are borne in racemes, so that this feature, together with the striped bark,
will always serve to identify it.

The box elder, or ash-leaved maple, is the odd member of the family,
for it has leaves totally different from those of the other maples that we
know in this country. Instead of a single, simple leaf, this maple has
a compound leaf with three to five leaflets. If it were not for the fruit,
which is a true maple " key," we should feel more inclined to call it an
ash — a feeling that is shown in one of the common names for the tree.
The box elder has been used for planting in the treeless regions of the
Middle West because it will endure dry weather and will grow rapidly
even on relatively poor soils. But the wood is weak and perishable and
the tree almost always grows crooked, especially if it is exposed to
winds; so that altogether it is not to be considered very valuable.

The Norway maple, which has been planted extensively as a shade
tree because of its rapid growth and heavy foliage, is a native of Europe
but does very well in this climate. The leaves bear a general resemblance
to those of the hard maple, but are much darker in color, usually larger,
and thicker. If one is in doubt about the tree, the milky sap from a
freshly broken leaf stem will distinguish it. In winter the leaf buds are
very large and the bark is smooth and dark-colored.

The sycamore maple, another European tree, is also planted to some
extent in this country although it does not grow so well in our climate
as does the Norway maple. The leaves are conspicuously three-lobed,
and are very broad compared with those of the native hard maple. The
margins of the leaves are serrated, somewhat like those of the red maple.

The most valuable and useful of all the maples is the sugar maple.
The wood is heavy, hard, and close-grained. It is used for furniture, floor-
ing, and many small wooden articles. It also makes one of the best
fire woods that our forests produce. The custom of making sugar and
sirup from the sap of this tree is well known and needs no special men-
tion here.

Besides the maples mentioned above, it is likely that many Japanese
maples will be found in parks and gardens. These small maples, rarely
larger than bushes, are remarkable for the beauty of their leaves.
5

132

THE OAKS OF NEW YORK

JOHN BENTLEY, JR.

A brave old oak

There are nearly fifty different kinds of oaks in the United States, and
if we should include the several varieties, some of which are indistinct,
the list would be so long that it would be discouraging to try to learn
all of them. Fortunately we can learn to distinguish those that are
common in New York. Although there are some fifteen or sixteen kinds
of oaks reported as growing in this State, we shall describe but ten. The
others are rare or of very local occurrence. It will be necessary to have
not only the leaves, but the acorns and sometimes the twigs and the winter
buds, in order to distinguish all the oaks described.

In the first place, we can divide the oaks into two general groups:
those that have acorns maturing in one season, known as the white oaks;
and those that have acorns maturing in two seasons, known as the black
oaks. A further distinction between these two groups is that the black
oaks have leaves the lobes of which are tipped with bristles, while the lobes
of the leaves of the white oaks are smooth and rounded. Between the
lobes are indentations which botanists call " sinuses." These sinuses
are variable and are often a help in identifying the different species.
On pages 136 and 137 is given a key for identifying the different species
of oaks. Note the use of the term sinus in this key.

133

As a family the oaks are very useful; but there is a great difference
between the several species, especially as to rate of growth, hardness of
wood, and usefulness of wood. In general the white oaks are harder
and more durable than the black oaks, and when a carpenter or a wood-
worker wants a piece of very hard, heavy, durable wood that will hold
its shape without shrinking, warping, or checking, he will be likely to
choose a piece of white oak in preference to any other kind, of oak. In
the market, swamp white oak passes for white oak and sometimes a
small quantity of chestnut oak may be included with true white oak;
but the wood of chestnut oak is not so strong and good as that of true
white oak.

In form the oaks present a great variety. White oak growing in the
woods has a long, clear stem for perhaps fifty or sixty feet and reaches
a height of over one hundred feet. In the open fields, where it has plenty
of room to develop a big crown, the form is likely to be short and round-
headed, with a stout trunk and with little of it clear of branches. The
oak always presents an appearance of great strength and sturdiness;
the winds of winter have little effect on its tough, strong branches but
these are frequently gnarled and irregular as a result of exposure to storms.
The acorns of the white oak will germinate soon after falling in autumn
if the conditions are favorable; but because so many acorns are eaten
by squirrels, and because so many others do not find the right conditions
of soil and moisture, only a small number succeed in growing to a size
that will enable them to live over the first winter.

Although a widely distributed tree, the white oak is found most
commonly on good moist soil in rich bottom lands or in protected hollows.
In the country adjacent to the Ohio River valley the white oak finds
the best conditions of soil, climate, and rainfall. It will grow also on
rather dry, stony soil, but it never reaches such good size under these
conditions.

Of the black oaks, the common red oak is the most desirable because
of the rapidity of its growth and the general quality of its wood. Although
not nearly so strong as white oak, it is heavy and rather hard and will
be useful where great strength is not required. The grain of the wood
is rather coarse and it never seasons so well as does the white oak. In
form the red oak develops a very large, wide-spreading crown, with a
number of large branches; but it almost always has a well-formed stem,
making possible the cutting of good saw logs from it. The red oak grows
farther north than any of our native oaks, and is not nearly so particular
as the white oak as to quality of soil.

The common black oak is of relatively little importance. The tree
does not grow to such good proportions as the red oak and the wood is

134

Bur oak

Swamp oak

Post oak Chestnut oak

Outline drawings for blackboard work

Scrub white oak Pin oak

Outline drawings for blackboard work

136

poorer in quality. It is used for railroad ties and rough timbers, but
it is not so durable as the red oak.

The scarlet oak is a much smaller tree than either the red or the black
oak and it is almost always found growing on sandy or gravelly soils.
Its form is not good enough to make it an important timber tree.

The two scrub oaks, which are really little more than shrubs, cover
vast areas that have been burned over and are often the obstacle to having
better trees on this kind of land. It is better, however, to have them
growing on the land than to have nothing at all, for in the latter case the
soil might be washed away by heavy rains; and perhaps we shall be able
to start more desirable kinds of trees where the scrub oaks are now grow-
ing, taking advantage of the protection that they afford.

KEY TO THE COMMON OAKS OF NEW YORK

A. Acorns maturing in one season; leaves with rounded lobes and
rounded sinuses WHITE OAKS

1 . Margin of leaf merely wavy-toothed, not cut so deeply as to be

called lobed

(a) Margin finely wavy-toothed Chestnut oak

(b) Margin coarsely wavy-toothed, more pointed than in

(a) Swamp white oak

2. Margin of leaf distinctly lobed; one pair of broad sinuses

cutting nearly to the midrib of the leaf, so that the upper
part of the leaf is much heavier and broader-looking than the

lower part. Acorn with a mossy cup Bur oak, or

Mossy-cup oak

3. Margin of leaf distinctly lobed sometimes very deeply cut,

with broad, sinuses

(a) Lobes usually seven or nine in number; acorns pointed;

cup enclosing not more than one fourth of the
nut White oak

(b) Lobes usually five in number; acorns not so pointed, and

cup enclosing one third to one half of the nut . . Post oak
A A. Acorns maturing in two seasons; leaves with pointed, bristle-
tipped lobes and rounded sinuses BLACK OAKS

i. Leaves green on both sides

(a) Sinuses very broad, broader than the lobes between

them

(i) Acorn small and flat, the nut almost hemi-
spherical. Usually found growing in moist,
rich soil on the banks of streams or the borders
of swamps Pin oak

137

(ii) Acorn slightly larger and more nearly round.

Kernel whitish. Usually prefers dry soils on

ridges and well-drained situations . . Scarlet oak

(b) Sinuses usually not so broad as the lobes between

them

(i) Leaves thick and firm; dark green, lustrous
above; more or less fuzzy on the under-
side Black oak

(ii) Leaves thin and firm; dark, dull green above;
on the lower side usually smooth, or with

fuzzy hairs near the veins only Red oak

Or by their acorns these two oaks can be
distinguished as follows:

Cup very flat, saucer-shaped Red oak

Cup not so flat, enclosing nearly half the

nut Black oak

2. Leaves green above, gray-green or yellowish green and
scurfy on the lower side; usually with only three lobes.
(Found only on Long Island) Blackjack

" What does he plant who plants a tree?

He plants a friend of sun and sky ;
He plants the flag of breezes free;
The shafts of beauty towering high;
He plants a home to heaven anigh,
For song and mother-croon of bird
In hushed and happy twilight heard —
The treble of heaven's harmony —
These things he plants who plants a tree."

HENRY CUYLER BUNNER

' The cattle also are very glad of a great tree,
They chew the cud beneath it while the sun is burning,
And there the panting sheep lie down around their shepherd.

" He that planteth a tree is a servant of God,
He provideth a kindness for many generations,
And faces that he hath not seen shall bless him."

HENRY VAN DYKE

It is better to observe for five minutes and draw for one, than to
observe for one and draw for five.

We may make our drawing lesson more interesting by telling
the class something about the object which they are to draw,
involving in our story facts that will tend to impress upon their
minds some of the most salient characteristics of the object. We
should encourage the children to discuss the object, drawing out
facts from their own observation. Certain kinds of trees, like
certain races of people, have a general similarity, yet every single
tree has an individuality of its own.

Let us apply a few essential questions that will help us to
determine at least the kind of tree it is, the race to which it
belongs ; for first we must get its general character, seeing its
big proportions and shape ; and later must search for its
individualities.

Is it tall for it's greatest width ?

How far does the trunk extend before dividing?

At what height do the lowest branches begin ?

What is their general direction ?

Do they appear to radiate from the trunk ?

How do the main branches compare in size with the trunk ?

Are they crooked or straight ?

The manner of branch growth must be studied carefully.

We see in our elm (Fig. 34) that the trunk divides at
about a fourth of its height into several main branches, while in
the cases of the pepperidge (Fig. 29) the trunk extends to the
very top of the tree, the branches being small in proportion to
the trunk, not varying much in size, and taking an oblique
downward direction. Notice the weird expression of these trees
with their crookedly bent tops, one side of each trunk being
almost devoid of branches.

The trunk of the sassafras (Fig. 30) continues nearly to the
top of this tree, while the large branches, though unsymmetrical,
give it a well balanced appearance.

Again in our picture of the thorn-apple (Fig. 31), we are at
once impressed with its irregular form, the branches on the
left taking a more oblique direction than those of the other side,
the trunk dividing a little short of half the height of the tree.

35.

Blocking-in the elm tree ( Fig. 34). The first work which the artist
does when he draws the tree.

140

We may now take up our lesson. Our subject is an elm tree
(Fig. 34) ; our medium, lead pencil ; our drawing to be rendered
in outline.

Material. — Almost any good drawing paper, white or buff in
color, will answer our purpose : 9x12 is a good size. Our
pencil should be of medium grade lead (F. or HB. ) of any
standard make, Kohinoor preferred.

If procurable, we should have a light drawing board 17x22
inches (here is an opportunity for the carpenters) to place the
paper on, otherwise a very stiff piece of cardboard ; or a large
geography book might answer. It is best, however, to fasten
our paper, which we cannot do in using the book. For fastening
the paper we shall need four thumb tacks for the corners.

A Faber or multipex pencil eraser is needed ; also a sponge
eraser with which to remove the light lines and clean the draw-
ing before lining it in.

Our position. — Our point of view will depend upon our subject,
but it is not well to be so near as to necessitate raising the head
in order to see the top of the tree. If we take longer than one
sitting for our drawing (which I do not think advisable, as we
must not choose too complicated a subject) we must mark our posi-
tion in order to again obtain the same point of view.

Position of the drawing-board. — Our paper must be placed on
the board with its edges parallel to those of the board. The
drawing-board should be held perpendicular, or nearly so, to the
direction in which it is seen, for if the board is tilted far back-
ward, it will be fore-shortened and our tree probably will have
been drawn longer than it should be.

Hoiv to look. — The tendency of the beginner is to see and draw
too much in detail. It is most essential that we look first for the
large shapes, the greatest dimensions ; next for the smaller ones ;
last for detail. It is not well for the pupils to work too close to
their drawings. They should occasionally sit well back in their
seats or get up and stand behind their chairs in order to obtain
the general effect of their drawing, to see that the big shapes are
right and that the spirit of the tree has not been lost.

As an aid to placing our drawing so as to best fill the space it
has to occupy , we may use what the French call a ' ' cherche -motif, ' '
the English, a finder. This is nothing more than a small

36. Working in the details with sharp lines. The original pencil sketch is
not followed exactly.

142

piece of stiff paper or cardboard, about 5x8 inches, in which is
cut a small rectangular opening ^xi inch ; the size may vary
somewhat. We may look through this opening, the card acting
as a frame to our picture. This will help us to decide whether
our subject will look better placed the horizontal or vertical
way of the paper. We may include more or less in the finder
by varying its distance from the eye.

Now, I am sure we would not place ourselves within a dozen
yards of our tree if we wished to get its general effect ; there-
fore, we must have plenty of foreground in our drawing. We
must give the eye a chance to look, allowing plenty of space
between the lowest point of our drawing and the lower edge of
our paper. We must also avoid crowding it to the right or left.

As the height of tree we are to draw (Fig. 34) is greater than
its greatest width, we find that it will fill the space best if placed
the vertical way of the paper. After indicating the extreme
height and width by four light marks, before carrying the draw-
ing further we must test these proportions by comparing the
width with the height, always testing the shorter dimension
into the longer, viz.:

To test the drawing. — Close one eye. The pencil may be used
to test the drawing by holding it in front of one at arm's length
(as in Fig. 33) perpendicular to the direction in which the object
is seen ; also revolving it in a plane perpendicular to the direc-
tion in which the object is seen, in order to compare one dimen-
sion with another. For example, hold your pencil horizontally
at arm's length so that its blunt end covers the outermost left-
hand point of the elm. Slide your thumb along the pencil till
it covers the extreme right-hand point ; retain that measurement
(keeping the same position in your chair, pencil always at arm's
length) ; revolve the pencil in the same plane until it coincides
with the height of the elm, at the same time lowering it so that
the end of the thumb covers the lowest point of the tree ; note
carefully the point that the blunt end covers ; raise the pencil so
that the end of the thumb covers that point, noting again where
the blunt end occurs and notice how many times, and over, the width
goes into the height. In our elm (Fig. 34) we find that the width
goes about once and six-sevenths, into the height, or a little

37-

The outline drawing complete, and the first pencil marks erased.

144

short of twice. If the latter statement is preferred, we must
bear in mind the proportion left over.

Do not use the scale side of a ruler or marks on the pencil or
object used in order to test the proportions. A scale or other
mechanical means should not be used in free-hand drawing. The
teacher should have a spool of black thread and should give a
piece about 2 ft. 6 inches long to each pupil. An eraser, a knife,
or some small article may be attached to one end of the thread.
By holding the weighted thread as a plumb-line in front of us, we
have an absolutely vertical line ; so by having it intersect a
desired point of our tree we may obtain the relative positions of
other points to the right and left of this intersected point.

Blocking -in. — We may conceive of the general shape of our
elm by looking at it with half-closed eyes. It appears in sil-
houtte. Now imagine lines joining its outermost points ;
this will give the general mass or shape of our tree. Now if
we represent these outermost points contained in these lines, by
sketching lightly these " blocking-in " lines, as they are called,
we obtain the general shape of the elm (Fig. 35). We must
emphasize the fact that these blocking-in lines be sketched in
lightly by holding the pencil near the blunt end, using a free-arm
motion. Now before going farther we again test these new-
points to see if they occupy their right positions in relation to
the height and width. Do not, however, transfer the measure-
ments from the pencil to the paper. This test is only to
obtain the proportion of one dimension to another. Having
tested these smaller dimensions we may draw lightly the main
branches.

After having indicated their general direction and character of
growth, we may indicate some of the smaller branches and twigs
(Fig. 36). All this work should be carried out without erasing ;
all corrections should be made by slightly darker lines.

Let us now sharpen our pencils to a good point and go over
the drawing with a fine dark line, carefully studying the charac-
ter and spirit of the tree. Now erase the lighter and superflu-
ous lines, as the dark lines remain distinct enough to indicate
our drawing.

Lining-in. — We may now take our pencil nearer the point and

H5

proceed to line-in the drawing, going over it with a definite
consistent line. If desirable, we may accent and bring out certain
parts of the tree stronger than others by darker or shade lines
and short strong markings called accents. These are especially
effective at the junction and underside of branches, and where
one wishes to give the object a nearer appearance. We
should be cautious in using them, however ; but lack of space
does not permit further discussion of the subject of accented
outlines.

We should also allow the pupils to make short ten or fifteen
minute " time sketches " of trees. In these, it is the spirit and
general eifect of the tree that we must strive for. Above all, we
must allow our little draughtsman to give his own interpretation
of the tree. A helpful suggestion as to proportion, etc., would
be in place, but we must allow his individuality to have as much
play as possible.

The suggestions given on these pages are necessary for the
beginner. Some of them are hard facts; but it lies with the teacher
to develop the aesthetic and artistic qualities lying dormant in
the pupil, ready to be moulded and started in the right direction.
. If you have confined the pupils to the flat copy, break away
from it ; allow them to create. Let them see the beautiful things
all about them. They will respond. Let them draw from nature
and still life. Train them to observe.

The early summer days, just before school closes, with their
bright sunlight and strong shadows, make many subjects inter-
esting as light-and-shade drawings. Fall with its brilliant color-
ing gives us a chance to use the color-box, while the early winter
twilights will bring many an interesting silhouette before our
boys and girls, which next day during the drawing hour may be
carried out in pen and ink.

The most successful teacher will be the one of sympathetic
nature whose love reaches out to the boys and girls, as well as
to all things beautiful. The most successful teacher will be the
one who endeavors to place the children where they may view
nature sympathetically and with the most intimate relationship.

146

These leaflets are designed to suggest means and methods by which
teachers may interest children in nature-study. The ultimate object
of our work is to inculcate a love for country life, and this can best
be done by interesting the coming generation in country things.
The teacher will also find nature-study to be directly valuable as a
means of education, or training the mind of the child. We want
your full co-operation and your unreserved criticism. Any com-
munication which you may send to us will receive prompt and
direct attention :

The following leaflets have been issued to aid teachers in the public
schools in presenting nature-study subjects to the scholars at odd
times :

1. How a squash plant gets out of the seed.

2. How a candle burns.
j. Four apple twigs.

4.. A children" s garden. For the pupils.

5. Some tent-makers.

6. What is nature-study f

7. Hints on making collections of insects.

8. The leaves and acorns of our common oaks.

9. The life- history of the toad,
to. The birds and I.

TI. Life in an aquarium.

T2. How the trees look in winter.

Bulletin 159 gives a general review of the Cornell Agricultural
Extension Work.

These will be sent free to all engaged in teaching in the public
schools of the State of New York.
Address,

Bureau of Nature- Study,

College of Agriculture,

Ithaca, N. K

TEACHER'S LEAFLETS

FOR USE IN THE PUBLIC SCHOOLS

PREPARED BY

NO. 13,
FEBRUARY, 1899.

THE COLLEGE OF AGRICULTURE,
CORNEL UNIVERSITY,

Issued under Chapter 67
of the Laws of 1898.

ITHACA, N. Y.

I. P. ROBERTS, DIRECTOR.

Evergreens, and How They Shed
Their Leaves,

BY H. P. GOULD.

ONE-BEARING evergreens are familiar to
everyone ; yet this familiarity is usually
with the trees as entire objects. We da
not often stop to analyze a tree in order to
find out what gives it its characteristic
appearance or to see what makes it look
as it does.

We will often find, if we stop to look,
that much of the character of a tree, — that

is, its general appearance or the way in which it impresses us, — is
due to the leaves and to their arrangement on the branches.
This is true of many of the evergreen trees.

Note to the teacher. — This leaflet has two particular objects : to teach how
evergreens shed their leaves, and to enable you to distinguish a few of the
evergreens which are most commonly met. These studies (and those sug-
gested in Leaflet No. 12) should be the means of adding much cheer to the
winter. Encourage pupils to make collections of cones, to observe when
they shed their seeds,and how long ( how many seasons) they remain attached
to the branch. Remember that mere identification of the kinds of trees is
not the highest type of nature-study.

Cones are good subjects for free-hand drawing. Beginners should draw
them in outline, omitting the shading. Encourage pupils to draw* single leaf-
clusters of the different pines, cautioning them to get the right number of
leaves in each case.

148

Why are certain kinds of trees called evergreen, in distinction
from those which are said to be deciduous? The reason is
obvious. One kind is always green from the presence of foliage,
while the other sheds all of its leaves every season. The ever-
green trees, like the pines and the spruces and firs, always appear
to be well covered with foliage, so it does not often occur to us
that these trees shed their leaves. And yet perhaps we can
recall happy hours when we used to play beneath some large pine
tree where the ground was carpeted with pine ' ' needles. ' '

The falling of the leaves of the maple trees or the oaks is a

38. Shoot of the common white pine, one-third natural size.

familiar sight, but who has seen the spruce leaves fall, and who
can tell when the pine needles drop ?

That the evergreen trees do shed their foliage, as truly as the
maples and the elms do, we will not question, for we can see the
fallen leaves under any tree. Look up into the top of a spruce
or pine. See that the interior is bare of foliage. The leaves are
towards the ends of the branches, where they receive sunlight.
Yet the branches which are now on the interior once bore leaves,
for we can see the leaf-scars.

It will be interesting to find out something about the leaves of
our common evergreens. Let us look at some of them.

149

THE WHITE PINE.

In Fig. 38 is shown a white pine branch. Notice that the
leaves are borne in bunches or clusters of five. Each bunch of
leaves is produced in the axil (or angle) of a minute scale-like
body, but this scale cannot usually be found except on the very
young growth. It has been worn away or
broken from the older growth by the wind
and the rain and the other forces of nature.

Another strange fact should attract our
attention. The leaves of the maples and
other deciduous trees are borne only on the
present season's growth; but this is not
the case in the pines, and kindred trees.
If we trace back the growth of the past
two or three years, we shall find that there
are as many leaves on the wood that is two
years old as there are on the last season's
growth ; and in many cases we can find
leaves on the part of the branch that is
three years old. This means that the pine
leaves or needles are two and sometimes
three years old when they fall. The Fig.
38 shows the falling of the leaves from the
different years' growth. The part of the
branch between the tip and A is the last
season's growth ; between A and B it is two
years old ; the part between B and C is
three years old. The part that grew four
seasons ago — beyond C — has no leaves.

The different season's growth is not indicated by distinct
"rings" as in the case of deciduous trees (See Leaflet No. 3),
but by the branching. Each whorl of branches about a limb
represents the end of a season's growth. A young pine tree, or
the younger limbs of an old tree, show this character very plainly.

Do the leaves of the pines and of the other evergreen trees fall
at the end of the growing season, as the leaves of most of the
deciduous trees do? Or do they gradually become lifeless and fall
at any season, from the force of the wind and other forces of

39-

Cone of white pine. It
has shed its seeds. Half
natural size.

150

nature ? Tie a large sheet of cloth in the top of some evergreen
tree, in such a way as to form a receptacle to catch the leaves.
Do you catch leaves in winter as well as in summer ?

There are several different kinds of pines, so we must picture
carefully in our minds the foliage of the white pine, for it is dif-
ferent from that of any others. The leaves are soft and very
slender, and from three to four inches long. The base of each
cluster of leaves is at first surrounded by a small sheath-like

40. Shoot of common pitch pine. One -ha If natural size.
body, but this falls away when the leaves are still very young.
A scar is left when the leaves drop and these scars can often be
seen on parts of the branches that are eight or ten years old.
Do the leaves of other kinds of trees make a scar when they fall ?
The white pine cones, in which the seeds are borne, are con-
spicuous objects. They are five or six inches long and slightly
curved. It will be interesting to find out if the seeds ripen the
same year in which they are formed. Perhaps a cone still con-
taining seeds can be obtained. Carefully tear it apart and see
where the seeds are attached. Red squirrels sometimes eat the
pine seeds. A white pine cone, which has shed its seeds, is shown
in Fig. 39.

This kind of pine is found widely scattered in New England,
New York and westward to Minnesota and Iowa and along the
Allegheny Mountains as far south as Georgia ; also in some parts
of Canada. It is a valuable lumber tree.

THE PITCH PINE.

This kind of pine is very different, in many respects, from the
white pine. Let us find some of the differences. Instead of
having leaves in bunches of five, it has them in clusters of three,
and the base of each cluster is inclosed by a
scaly sheath which does not fall away as in
case of the white pine ; neither does the little
scale-like body upon the branch, in the axil of
which the leaf -cluster is borne, fall away, but
it may be found just below the leaf, and even
on branches that are several years old. Some-
times a sheath is found with only two leaves.
We shall want to know, too, how old the
leaves are when they fall. Do they remain on 41- Cone of pitch pine.

One-half natural size.

the tree longer than the white pine leaves do ?

Again, instead of being soft and slender as the white pine
leaves are, we shall find that these leaves are rigid and large in
comparison, and stand out straight from the branches. The
shape of the leaves is also distinct from the white pine needles.
See if you can find any other differences.

A pitch pine branch is shown in Fig. 40. The part between
the tip and A is the past season's growth. Observe the foliage
on the part that is two years old. Part of it has fallen. We
often find it on growth which is older than this ; but in this
specimen there are no leaves on the three-year wood.

The cone of the pitch pine is very unlike that of the white
pine. Fig. 41 gives a good idea of one which has shed its seeds.
Compare this with Fig. 39 ; or, better, examine the two kinds of
cones side by side. The pitch pine cones are sometimes borne in
clusters of two or more and they persist, — that is, remain on the
tree for several years after the seeds have ripened and scattered .

152

Notice how the new cones are borne with reference to last sea-
son's growth. Are they attached to the tip of a branchlet? Or
are they closely attached to the side of a branch ? Figs. 42 and
43 will help us answer this question. The little cones in Fig. 43,
near the tip of the twig, are just beginning to form.

The pitch pine
usually grows in
sandy or rocky
soil and is
found in the
United S tates
along the Atlan-
tic coast to Vir-
ginia, along the
mountains to
Georgia, west-
ward to Western
New York, East-
ern Ohio, Ken-
tucky and East-
ern Tennessee.
It has little value
as timber, be-
cause it does not
grow large
enough,

SCOTCH AND AUSTRIAN PINKS.

In the same manner, other pines may be studied. Fig. 44
shows a cone and bit of foliage of the Scotch pine, and Fig. 45
the Austrian pine. These cones grew the past season and are
not yet mature. After they ripen and shed the seeds which they
contain, they will look something like the cone in Fig. 41. The
Scotch pine has short and blue-green needles. The Austrian
pine is coarser, and has long dark-green needles.

There are but two leaves in a cluster on these kinds of pines
and we shall find that the sheath which incloses the base of the
leaf -cluster is more conspicuous than in either the white or pitch
pines. Do the leaves persist in the Scotch and Austrian pines

42. Pitch pine. One-third natural size.

43- Pitch pine, showing young cones. Half natural size.

I
44. Scotch pine. Half natural size.

154

longer than they do in the others we have examined ? Study

the cones of these and other pines.

The Scotch and Austrian pines are not native to this country,

but are much grown for ornament. They can be found in almost

any park, and in many other places where ornamental trees are

grown.

THE NORWAY SPRUCE.
The leaves of spruce trees are borne very differently from

those of the pines. Instead of being in clusters of two or more,

they are single
and without a
sheath at the
base; neither are
there scale-like
bodies on the
branches where
the leaves are
borne. Notice,
too, that the
leaves have a
very short stem
or petiole.

The leaves of
the Norway
spruce are about
one inch long,
although the
length varies
more or less in
different parts of
the tree and in
different trees.
They are rather
stiff and rigid
45. Austrian pine. One-third natural size. and sharp-

pointed. In a general way, the leaves are four-sided, though
indistinctly so.

It will be interesting to study the position which the leaves

155

take on the branches. A hasty glance might give us the impres-
sion that the leaves are not produced on the under side of the
branches ; but a more careful examination will convince us that
there are nearly as many on the under side as on the upper.
The leaves are all pointing outward from the branch and as
nearly upward as is possible. In other words, the leaves grow
toward the light.

We must not forget to see how long the leaves of the Norway
spruce persist and to find out when the leaf-scars disappear.
We can find leaves that must surely be six or seven years old

46. Twig of the common Norway spruce. Half natural size.
and sometimes we can find them even older than this. The leaf-
scars, too, remain along time. The falling of the leaves is illus-
trated in Fig. 46. It shows the extremities of a limb which is
eight years old. The part between the tip and A is last season's
growth ; between A and B it is two years old ; and beyond B is a
part that grew three seasons ago. The section beyond C is six
years old ; from C to D is seven years of age. The four years'
growth of this limb not shown in the drawing was as densely
covered with foliage as is the part shown in the upper figure ; but
there are not many leaves between C and D (seven years old) and
none on the eight-year-old wood (except those on the branchlets,
and these are younger.)

156

The cone of the Norway spruce is nearly as long as that of the
white pine, but it is not so rough and coarse as the white pine
cone is. The cones are usually borne on the tips of small branch-
lets, although occasionally one is found borne in the manner shown
in Fig. 47. The cones usually fall the first winter.

The Norway spruce is not a native of
this country, but, like the Scotch and
Austrian pines, it was introduced from
Europe and is grown very widely as an
ornamental tree. It is the commonest
evergreen in yards and parks.

THE BLACK SPRUCE AND ITS KIN.

There are several different kinds of
spruces which we find growing in
our forests and swamps, and sometimes
these are planted for ornament.

A sprig of foliage and a cone of one
of these, — the black spruce, — is shown in
Fig. 48. The foliage is not very unlike
that of the Norway spruce, but the cones
are very small in comparison. They are
about one inch long, though they vary
considerably in size. Before they open
they are oval or plum-shape, but when
mature and the scales of the cone have
expanded, they are nearly globular.
They are often borne in clusters, as well
as singly, and persist for many years
after the seeds have fallen. The posi-
tion of the cones will depend upon their age. When young,
they point upward, but they gradually turn downward.

The white spruce resembles the black very closely in general
appearance. The leaves of the white spruce have a whitish or
dusty looking tinge of color and when crushed or bruised, give
forth a peculiar disagreeable odor. The cones vary in length
from an inch to two inches, and in shape are more cylin-
drical or finger-shaped than the cone of the black spruce.

47. Cone of Norway spruce.
Half size.

157

The foliage of the red spruce lacks the whitish tinge of color
of the white spruce and the cones, which are from one inch to
two inches in length, are obovate in shape — that is, the
widest place is through the upper part of the cone, and from this
point it gradually tapers to the tip. They seldom persist longer
than the second summer.

The leaves of all these different kinds of spruces vary greatly
in length, thickness and sharpness of point, according to the part
of the tree on which they grow, and their surroundings. The
shedding of the leaves on these or other spruces can be determined
as easily as in the Norway spruce.

These three spruces like a cold climate and grow in many
sections of northern United States and Canada and farther

48. Black spruce. Half natural size.

south in the mountains. They are sometimes all found growing
together, but the black spruce likes best the damp, cold swamps,
while the others grow best on the drier and better drained
lands. The black spruce is commonest. The red spruce is
least known.

THK BALSAM FIR.

This is another evergreen tree which grows naturally in the
cold, damp grounds of the northern United States and Canada, and
to some extent in the eastern states as far south as West Virginia.

The foliage is borne in much the same manner as that of the
spruces ; yet there are interesting differences in the characters of
these two kinds of leaves. Perhaps the most noticeable difference
is in the shape ; and the color of the fir leaves will attract our atten-
tion because the under side is a silvery color, while the upper side is
green. What is the nature of the tip of the leaf? and how does

158

it compare with the pines and spruces in this respect ? Does the
leaf have a stem or petiole? or is it attached directly to the
branches without any stem? How are the leaves shed ?

The cones are about three inches long and present a rather
delicate appearance. It will be interesting to determine the
position of the cones, that is, the direction in which they point,
and to learn if it is the same when they are young that it is after
they have matured.

The grayish colored bark of the trunk and limbs bears many
*' blisters " from which Canada balsam is obtained.

THE HEMLOCK.

A hemlock twig is an interesting object. It may have many
characters in common with the spruce and fir, yet the impression
which we get from it, or from a large hemlock tree, is entirely
distinct. The arrangement of the leaves and the gracefulness of
the drooping branchlets are most pleasing. We are lead to
examine it more closely. We notice that the leaves appear to be
borne in two more or less regular rows, — one on each side of the
branch or twig ; but in reality they come from all sides of the
branch, and it is the position which the leaves assume that gives
this two-rowed appearance.

The leaves have a short petiole or stem, and this stem rests
along the side of the branchlet in such a direction that the leaves
are placed in single rows on either side of the branch. The
petioles of the leaves are nearly parallel with the branch while
the leaves often make a decided angle with the petiole. This
fact can best be brought out by carefully examining a small twig.

While we are noting the arrangement of the leaves on the
branchlets, we should also take notice of the points of similar-
ity and difference between these leaves and the spruces and firs.
We shall find that there is more in common, at least so far as
shape and color are concerned, between the hemlock and fir than
between the hemlock and spruce.

The small delicate cones, borne on the tips of the branchlets, will
also attract our attention (Fig. 49.) We may wonder at their small
size, for they are only about three-quarters of an inch long, and
very delicate, yet a second glance at the tree will impress us with

159

the number of cones which the tree bears : and we conclude that,
although the cones may be small, yet there are so many of them
that there will be no lack of seeds.

It is more difficult to trace the age of a hemlock limb than of
many other kinds of trees, yet we can easily determine that many
of the leaves are several years old when they fall.

The bark of the hemlock is used in tanning leather. The tree
is much used for lumber. Where does it grow ?

THK ARBOR-VIT.^.

One might almost wonder, at first sight, if the arbor-vitse
(often, but wrongly, called white cedar) has any leaves at all.

Spray of the hemlock. Two-thirds natural size.

It does possess them, however, but they are very different in size
and shape from any of the others which we have examined.
They are small scale-like bodies, closely pressed together
along the sides of the branchlets, in four rows. L,eaves pressed
to the branches in this manner are said to be "appressed."
The leaves of the arbor- vitae are so close together that they overlap
one another. The leaves are of two distinct shapes, sometimes
known as the surface leaves and the flank leaves. The former are
located on what appears to be the flattened surface of the branch-
lets, while the latter are on the sides or edges. See Fig. 50.
If we carefully look at the leaves, we shall notice a raised spot

i6o

near the point or tip. This is said to be a resin gland. This
gland can be seen more plainly on the surface leaves that are
two years old.

Most of the leaves persist for at least two and sometimes
three years ; but even older ones can be found. These older
leaves, however, do not exist as green active leaves, but merely as
dried up and lifeless scales. These lifeless leaves, are probably
detached from the branches by the forces of nature.

The Arbor-vitae. Nearly full size.

The cones are even smaller than the hemlock cones. They are
borne in the axils of the leaves in the same manner as the branch-
lets and are not conspicuous unless one is close to the tree.

The arbor- vitae is much planted for hedges and screens, as well
as for other ornamental purposes. There are many horticultural
varieties. The tree is abundant in a wild state in New York.

Summary on the Kinds of Common Evergreens.

The white pine (Pinus Strobus). — Leaves in clusters of five, soft
and slender ; cones five or six inches long, slightly curved ;
bark smooth except on the trunks and larger limbs of old
trees, where it is fissured.

The pitch pine (Pinus rigida). — Leaves in clusters of three, from
three to four inches long, rather rigid ; cones two to three
inches long, often in clusters of two or more but frequently
borne singly, persisting long after the seeds have been shed ;
bark more or less rough on the young growth and deeply
fissured on the trunks of old trees.

The Scotch pine (Pinus sylvestris). — Leaves usually in clusters of
two, from two to four inches long, rigid, of a bluish-green
hue when seen in a large mass on the tree ; cones two to three
inches long and the scales tipped with a beak or prickle.

The Austrian pine (Pinus Austriaca). — Leaves in clusters of two,
five or six inches long and somewhat rigid, dark green in
color and persisting for four or five years ; cones about three
inches long, conical in shape and scales not beaked or pointed
as in the Scotch pine.

The Norway spruce (Picea excelsa). — Leaves borne singly, about
one inch long, dark green, four sided ; cones about six inches
long, and composed of thin scales, and usually borne on the
tips of branchlets. The small branches mostly drooping.

The black spruce (Picea nigra). — In general appearance, this is
not very unlike the Norway spruce, but the small branches
stand out more horizontally and the cones are only one or
one and one-half inches long, recurving on short branches.
The cones persist for several years after shedding the seed.

71ie white spruce (Picea alba). — Leaves about one inch long,
having a glaucous or whitish tinge ; twigs stout and rigid,
of a pale greenish white color ; cones from one to two and one-
half inches long, more or less cylindrical or " finger-shape,"
and easily crushed when dry.

The red spruce (Picea rubra). — The foliage lacks the whitish
tinge of the white pruce and is of a dark or dark yellowish
color ; twigs stouter than those of the black spruce and not

162

so much inclined to droop ; cones about one inch long,
obovate and usually falling by second summer.

The hemlock (Tsuga Canadensis). — Leaves about one-half inch
long, flat with rounded point, green on the upper side, whit-
ish beneath, and borne on short appressed petioles ; cones
about three-quarters of an inch long, oval or egg-shape, and
borne on the ends of small branchlets and often persisting
for some time.

The balsam fir (Abies balsamea). — Leaves narrow, less than one
inch long, borne singly, very numerous and standing out from
the branchlets in much the way of the spruce ; cones about
three inches long, cylindrical, composed of thin scales and
standing upright on the branches, or recurved ; bark smooth,
light green with whitish tinge.

The arbor-vita (Thuya occidentalis) . — Leaves very small, scale-
like and over lapping one another in four rows, adher-
ing closely to the branchlets ; the cones oblong and small, — a
half inch or less in length, — and composed of but few scales.

For further information respecting nature-study, address,

Bureau of Nature- Study*

Cornell University,

Ithaca, N. Y.
Or,
I. P. Roberts,

Director College of Agriculture.
L. H. Bailey,

Chief of Bureau of Nature- Study and Reading -Course.
John W. Spencer,

Deputy Chief.

Bulletin 68. August, 1894.

Cornell University Agricultural Experiment Station.
HORTICULTURAL DIVISION.

The Cultivated Poplars;

WITH REMARKS UPON THE PLANTING
OF GROUNDS.

By L. H. BAILEY.

PUBLISHED BY THEC UNIVERSITY.

ITHACA, N. Y.

1894.

ORGANIZATION.

BOARD OF CONTROL:

THE TRUSTEES OF THE UNIVERSITY.

STATION COUNCIL.
President, JACOB GOULD SCHURMAN.

Hon. A. D. WHITE, - Trustee of the University.

Hon. JOHN B. BUTCHER, - President State Agricultural Society.

Professor I. P. ROBERTS, - Agriculture.

Professor G. C. CAUDWELL, - Chemistry.

Professor JAMES LAW, - Veterinary Science.

Professor A. N. PRENTISS, Botany.

Professor J. H. COMSTOCK, - Entomology.

Professor L. H. BAILEY, - Horticulture.

Professor H. H. WING, Dairy Husbandry.

Professor G. F. ATKINSON, Cryptogatnic Botany.

OFFICERS OF THE STATION.

I. P. ROBERTS, Director.

E. L. WILLIAMS, - - Treasurer.

H. W. SMITH, Clerk.

ASSISTANTS.

M. V. SLINGERLAND, Entomology.

GEO. C. WATSON, - Agriculture.

G. W. CAVANAUGH, - Chemistry.

E. G. LODEMAN, . ... Horticulture.

Office of the Director, 20 Morrill Hall.

Those desiring this Bulletin sent to friends will please send us the names
of the parties.

BULLETINS OF 1894.

62. The Japanese Plums in North America.

63. Co-operative Test of Sugar Beets.

64. On Certain Grass-Eating Insects.

65. Tuberculosis in Relation to Animal Industry and Public

Health.

66. Test of Cream Separators.

67. Some Recent Chinese Vegetables.

68. The Cultivated Poplars.

THE CULTIVATED POPLARS.

I. GENERAL REMARKS.

There has been little attempt in experiment station literature to
discuss matters of ornamental gardening. The so-called practical
problems connecting directly with bread-winning have necessarily
and properly absorbed the energies of investigators. But the
ornamentation of rural and suburban homes is quite as much
within the province of experiment station work ; and it should
also be remembered that the growing of plants is itself an indus-
try which enlists a vast amount of capital, and this nursery busi-
ness has received little direct and explicit aid from experiment
station publications. The present essay is undertaken for the
double purpose of explaining certain fundamental principles in
landscape gardening — a subject to which the poplars readily lend
themselves — and of unraveling a web of difficulties respecting the
species and varieties of poplars, into which the nursery catalogues
seem to have fallen. An investigation of the botanical and horti-
cultural features of the poplars has been assiduously prosecuted for
upwards of two years, and the writer has had the free use of var-
ious nurseries and plantations in Western New York and the aid
of botanists in many parts of the country. As a group, the pop-
lars possess comparatively small value in landscape planting, but
this very fact affords me the opportunity I seek to press home
the fallacy of certain common practices amongst planters.

At the outset, I must be allowed to explain that landscape gar-
dening is the embellishment of grounds in such fashion that they
shall possess landscape or nature-like effects. This definition at
once removes from our consideration all the formal effects of
flower-beds and sheared trees, which, while useful at times, bear
no closer relation to landscape gardening than a cup of paint bears
to the fine art of painting. In other words, a landscape garden —
and that should mean every country yard, however small or sim-
ple— should have in it the elements of a picture. It should appear
to have one thought or feeling running through it all, and this is

206 BULLETIN 68.

a condition which is impossible when trees or bushes or flower-
beds are scattered all over the place, for in such case one is at-
tracted by these individual and detached objects and is not
particularly impressed with the place as a whole or as a unit.
Such a yard is a nursery. An artist would not care to paint such
an area. If a yard is to be a picture, it must have a sense of
frame- work about it, — certain strong groups of bushes or trees
about the borders, and the central area should be a more or less
open greensward with very cautious planting. The different parts
are then in masses or in bold contrast, and the place has character.
At the same time, the partial shutting off of the surrounding
areas sets bounds to the place, defines it, and makes it to appear
personal, snug and home-like. One should learn that it is not
plants which make a place attractive, but the arrangement of
plants. In fact, many otherwise attractive places are ruined by
a wealth of good plants scattered without purpose over the lawn.

It is but a corollary of this discussion to say that plants which are
simply odd or grotesque or unusual should be used with the great-
est caution, for they introduce extraneous and jarring effects.
They are little in sympathy with a true landscape garden. An
artist would not care to paint an evergreen sheared into some gro-
tesque shape. It is too formal and it has no elements of true
beauty. It is simply curious, and shows what a man with plenty
of time and long pruning shears can accomplish.

This leads me to one of the proper subjects of this paper, the
planting of the Lombardy poplar. Fortunately, this tree is less
planted in New York than in many western states. Its chief
merits to the average planter are the quickness of its growth and
the readiness with which it multiplies by cuttings. But in the
north it is apt to be a short-lived tree and it suffers from storms,
and it has few really useful qualities. It may be used to some
advantage in windbreaks for peach orchards and other short-lived
plantations, as explained in Bulletin 9 of this station ; but after
a few years a screen of I^ombardies begins to fail and the habit of
suckering from the root adds to its undesirable features. For
shade, it has little merit, and for timber none. People like it
because it is striking, and this, in an artistic sense, is its gravest
fault. It is unlike anything else in our landscape, and doesjnot

THE CULTIVATED POPLARS.

207

fit into our scenery well. The Lombardy should rarely, if ever, be
seen as a single specimen ; and above all, its formality and stiffness
should not be emphasized by planting it in rows along country roads.
A row of lyombardies along a roadside is like a row of exclamation
points !

But the tree can often be used to good effect as one factor in a
group of trees, where its spire-like shape, towering above the sur-
rounding foliage, ^^^^^™
may lend a spirit-
ed charm to the
landscape. It
combines well in
such groups if it
stands in visual
nearness to ch im-
neys or other tall
formal objects.
Then it gives a
sort of architect-
ural finish and
spirit to a group
of trees ; but the
effect is general-
ly lessened, if
not altogether
spoiled, if more
than one Lom-
bardy is in view.
One or two speci-
mens may often
be used to give
vigor to heavy
plantations
about low build-
ings, and the ef-
fect is generally
best if they are
seen beyond or at the rear of the building. Now and then one

Attractive Group oj Lombardy Poplars.

208 BULLETIN 68.

sees a picturesque clump of L,ombardies standing alone, like that
shown upon page 207. Here the one original tree has given rise
to a varied progeny of sprouts, and the mass has a freeness of outline
which can never be obtained in a regularly planted clump of these
trees from which the suckers are continually removed. This partic-
ular clump is one of the most picturesque objects in a sweeping
landscape near Perry City, Schuyler County, N. Y., but its excel-
lence is purely accidental.

Another feature of common ornamental planting which is well
illustrated in the use of poplars, is the desire for plants simply
because they grow rapidly. A very rapid-growing tree nearly
always produces cheap effects. This is well illustrated in the
common planting of willows and poplars about summer places on
lake shores. Their effect is almost wholly one of cheapness and
temporariness. There is little that suggests strength or durability
in willows and poplars, and for this reason they should always be
used as minor or secondary features in ornamental or home
grounds. , Where quick results are desired, nothing is better to
plant than these trees, but better trees, like maples, oaks, or elms,
should be planted with them and the poplars and willows should
be removed as fast as the other species begin to afford protection.
When the plantation finally assumes its permanent characters, a
few of the remaining poplars and willows, judiciously left, may
afford very excellent effects ; but no one who has an artist's feel-
ing would be content to construct the frame work of his place of
these rapid-growing and soft- wooded trees.

I have said that the legitimate use of poplars in ornamental
grounds is the production of minor or secondary effects. As a
rule, they are less adapted to isolated planting as specimen trees
than to use in composition, — that is, as parts of general groups of
trees, where their characters will serve to break the monotony of
heavier foliage. The poplars are gay trees, as a rule, especially
those, like the aspens, which have a trembling foliage. Their
leaves are bright and the tops are thin. A few of them injudi-
cious positions give a place a sprightly air. I especially love the
common aspen or Populus tremuloides of our woods (Ffg. 14).
Its light dancing foliage and silver-gray limbs always cheer me,
and its autumn color is one of the purest golden-yellows of our land-

THE CULTIVATED POPLARS. 209

scapes. I like to see a tree of it standing out in front of a group
of maples or evergreens. Its whole attitude is then one of famir- -
iarity.

The cottonwood is perhaps the best of all our poplars as a single
specimen. It makes a noble tree, spreading its gray branches far
and wide. But like the aspen, it is cheerful and restive. One is
not moved to lie under it, as he is under a maple or an oak. Its
leaves rustle with the lightest movement of air. The ripple of
its foliage always recalls to my mind the play of wavelets upon a
pebbly shore. The day is never so dark, but the cottonwood
reflects a flood of light.

Some of the forms of the black poplar of Kurope are especially
satisfactory for the production of lively effects in planting. Of
these, I know of none better than the form known to nurserymen
as Populus elegans. It has a most pleasing light and tremulous
foliage, the effect of which is heightened by a twiggy character of
growth and a reddish cast to the leaf-stalks and young shoots. It
is an elegant tree, and well adapted to planting in front of heavier
foliage in the most conspicuous portion of the grounds.

Some of the silver or white-leaved poplars produce the most
striking contrasts of foliage, especially if set near darker trees.
Bolle's poplar {Populus Bolleana of the nurseries) is one of the best of
these trees. Its habit is something like that of the L,ombardy.
The upper surface of the deeply lobed leaves is dark dull green,
while the under surface is almost snowy white. Such emphatic
trees as this should generally be partially obscured, by planting
them in amongst other trees so that they appear to mix with the
other foliage, or else they should be seen at some distance. Other
varieties of the common white poplar or abele are occasionally
useful, although most of them sprout badly and may become a
nuisance. But the planting of these immodest trees is so likely to
be overdone that I scarcely dare recommend them, although,
when skilfully used, they may be made to produce most excellent
effects. If any reader has a particular fondness for trees of this
class (or any others with woolly-white foliage) and if he has only
an ordinary farm-yard to ornament, let him reduce his desires to
a single tree, and then if that tree is planted well on the inside of
a group of other trees, no harm can result !

2io BULLETIN 68.

There are various weeping and grotesque horticultural varieties
of the poplars, as of other trees. Concerning the use of these, I
need only say that they are curiosities and that they should not
be given prominent positions directly in front of the house. I
think that no one will care to dispute me if I say that a person
who fills his front yard with such specimens, has little apprecia-
tion of natural objects. A few grotesque specimens in positions
of secondary importance may be desirable, as in a side or back
yard, but one will find that the more he cultivates a love of nat-
ural scenery the less he cares for mere monstrosities.

I may seem to have placed myself in the position of writing a
bulletin upon a group of trees which, upon the whole, I should
be quite as willing to discourage as to augment ; but my object
has been rather more, as I intimated at the outset, to point out
certain common defects in habits of thinking about ornamental
trees, and to discourage the use of trees simply because they are
odd, quick-growing and cheap. I wish that there were fewer
L/ombardy poplars in many parts of the country, fewer of the
ugly white or silver poplars, and more of the American and
European aspens, of the large-toothed aspen, of the cottonwood,
and the Russian Certinensis poplar. Many of the species are
excellent for covering sand-hills — for which the white poplar is
well suited — or rough or waste places, and they are capable of
adding much light and cheer to a yard. But planters are too
prone to use certain ones over freely.

Poplars are often disagreeable upon the lawn because of the
abundance of down or wool which they give to every breeze in
May and June, when the seed-pods burst. There is really little
occasion for this annoyance, however. The poplars are dioecious,
— that is, the male and female flowers are upon different trees
(although bath sexes are rarely upon the same trees in the cot-
tonwood). Nurserymen, therefore, should grow only the male
specimens. The cuttings from a male tree — or one producing
no cottony seeds — will give progeny of the same character. Of
the L,ombardy, there is only the male sex in the country, the
female never having been introduced, or at least not distributed,
so far as I know ; while the weeping willow is represented only by
the female plant. Some of the speciesand varieties are worth plant-

THE CULTIVATED POPLARS. 211

ing for the catkins which are produced so freely in early spring.
The European aspen (Populus Tremula) is particularly desirable in
this respect (Fig. 13); and this species also has a most interesting
habit and foliage.

It should be said, in passing, that most of the poplars are
hardy trees and thrive in a great variety of trying situations.
This, together with the ease of propagation and their cheapness,
combined with free and rapid growth, makes them the best of
trees for nurse plantations, — that is, for temporary shelter for
other trees and bushes. In this respect the common aspen poplar
is one of the most valuable of all trees in the reforestation of
American lands. It springs up quickly in clearings, and during
its comparatively short life holds the soil and protects other vege-
tation and finally contributes its own substance to the mainten-
ance of the stronger forests. In this manner it has exerted a
most powerful effect upon the configuration of our forest areas
and upon the fertility of the land from remote time. The same
qualities make it valuable, in many instances, in extensive
ornamental plantings.

The recent introduction of Russian poplars has added consid-
erable confusion to nursery lists, and it was this fact which first
led me to take up this inquiry. The chief merit of the Russian trees
is for planting in the northwestern prairie states, but all of them
are worth attention for exposed localities in this state, as well as
for ornamental planting. I am convinced that the so-called
Populus Certinensis (properly P. laurifolia) is one of the very best
trees to plant where quick results are wanted and where some
feeling of strength and durability is also desired. The best dis-
cussion of these Russian poplars which I know is contained in
Bulletin No. 9 of the Minnesota Experiment Station by Professor
S. B. Green, published in 1889. The following is a more recent
sketch of these trees by the same author, prepared for this occa-
sion :

"Russian Poplars in the Northwest. — In the arboretum of the
Minnesota Experiment Station are 1 2 kinds of Russian poplars
that were received from the Iowa Agricultural College. Most of
them have been grown in our collection for seven years, and some
of them have been tried for a much longer period in other parts

212 BULLETIN 68.

of Minnesota, in Iowa and the Dakotas, but not long enough any-
where in this country to warrant final conclusions. Those who
live in locations naturally in timber can hardly understand the
importance of the genus, to which these trees belong, to the pio-
neers on the wind swept prairies. The ease with which many of
them are increased, their rapidity of growth, great hardiness
against extremes of heat and cold, excessive moisture, and pro-
longed drouth, make them widely sought as pioneer trees in
most severe locations, for the formation of wind-breaks and for
shade from the scorching sun.

"I would not be understood as recommending the general
planting of poplars where our finer deciduous trees readily suc-
ceed, but for a strong effect in the shortest time in severe locations
they have no rival except the large growing willows, which may
generally be used with them to advantage. Among the collec-
tion of poplars commonly referred to as of Russian origin, are
trees having a great variety in growth and foliage, so that by the
judicious use of them alone one can secure very good effects in
landscape planting. They are not, however, and never have
been, represented as new species, but as hardier forms of species
already introduced into this country, and in the following notes I
have- grouped the kinds under the several heads where they evi-
dently belong, using their nursery or horticultural names. Aside
from the few exceptions noted, they are all easily increased
from hard wood cuttings made in the fall or spring.

' ' ANGULATA CLASS — Young growth plainly marked with ridges
or angles.

Dudley's Popuhts [properly P. balsamifera, var. viminalis\.
Growth only moderate ; when young rather upright in habit, but
somewhat pendulous when old. Our older specimens have been
badly injured by leaf rust in dry summers, and on this account I
have ceased propagating it. The leaves are broadly lanceolate,
very wavy on the edges and the young branches very angular.

' ' P. betulifolia is probably the same species as P. nigra of the
eastern nurseries. It makes a tree that is rather open in habit,
inclining to a straight trunk with branches coming out at nearly
right angles. The foliage remains bright and fresh even in dry
sod land in severe seasons. It is not especially valuable for tim-

THE CULTIVATED POPLARS. 213

ber but 'is interesting and useful for contrasting with other trees ;
leaves very thick, very large and broadly deltoid, much larger
and broader than leaves of the cotton wood under like conditions.

' ' Wobsky Poplar. One of the most distinct of its class ; of
rapid growth and open regular habit. As a timber tree it is up-
right and valuable, but it seems to be more susceptible to the
work of the poplar borer than other kinds and it occasionally
loses its foliage in dry places. On account of these weaknesses
it will not be largely planted in this section, but occasional trees
may often be used to give variety. The leaves are large, ovate
heart-shaped, stiff and very flat, of a shiny blue-green color on
the upper and a light green on the lower side. Buds large and
sticky. The young growth is only slightly angular.

' ' P. Certinensis \P. laurifolia of botanists] was introduced into
this country and disseminated by Arnold Arboretum. It is per-
haps the best of the collection for general prairie and ornamental
planting in this section ; perfectly hardy even in the severest ex-
posures and rarely, if ever, affected with leaf rust which so often
checks the growth of the cotton wood. Its timber makes very
good siding for buildings and floors, and answers many of the
purposes for which pine is generally used. It does not warp or
crack like our native cottonwood. It is rather upright in form,
with thick leathery leaves and of very rapid growth. It does not
grow quite as fast as the native cottonwood nor resist the attacks
of the leaf beetle so successfully, but it is a much longer-lived
tree and stands close planting very much better. It is grown
readily from cuttings, which in our forest plantation made a
growth of a trifle aver 12 feet in three years from half-inch cut-
tings planted eight inches apart in rows eight feet asunder.
The leaves are thick and leathery with a wavy edge. The new
wood is strongly angular. [The form of leaf is shown in Figs.
7 and 8.]

"The Populus Petrovski so closely resembles P. Certinensis
that I think them one arid the same thing. Professor Budd ob-
taided this in Russia and thinks it different from the latter. If
this is true it does not show its characteristics until older than
any specimen we have.

214 BULLETIN 68.

" The poplar known as P. pyramidalis wc.fastigiata is evident-
ly the Russian form of the Lombardy, if not the same thing. It
has been introduced in the hope that it would prove hardier and
longer lived than the common form, but in our experience of
some seven years, young trees of either form have never been in-
jured in this vicinity. It may, however, prove to be a longer
lived tree than the common Lombardy, which is well known to
be quite hardy, even in somewhat severe locations, when young,
but to be very short lived on the dry prairies of the Northwest.
It is, however, interesting to know that while the common Lom-
bardy poplar is an almost worthless tree in most parts of Minne-
sota, yet near Duluth and along Lake Superior it is quite a success.

" BALSAMIPKRA CLASS. — With large sticky buds and young
gi owths free from ridges or angles.

11 Populus balsamifera of Asia, as we have it, is probably the type
of which P. laurifolia and P. Sibirica var. pyramidalis of
horticulturists are but variations. The lamented Chas. Gibb
said he saw in the botanical gardens at Kazan a specimen of this
two feet in diameter and 50 feet high, and although it resembled
P. Sibirica when young, it is quite different from it in form
when old. Hither of the next two kinds are preferable to it for
planting, as the leaves of this have an unpleasant way of curling
together.

"P. Sibirica var. pyramidalis [a form of P. balsamifera, var.
intermedia of botanists] , makes a fair growth and is desirable for
ornamental planting. I think the foliage will endure more hard-
ship than the P. balsamifera, to which it is similar in form.

" P. laurifolia [of horticulturists, but P. balsamifera, var.
intermedia of botanists] is the best of this class. It is little slower
growth than the P. Certinensis but like it healthy, vigorous and a
good timber tree, and much superior to the cottonwood for lum-
ber or fuel. Its thick leaves withstand the hottest, dryest air of
the West, either standing alone or in shelter belts. The leaves
are thick and leathery, oval in form, a smooth clear white on the
under side, and a bright clear green on the upper ; generally flat,
but sometimes a little folded.

' ' WHITE POPLAR CLASS. — The typical Russian form of this is
rather more upright than the common white poplar and does not

THE CULTIVATED POPLARS. 215

sprout so much. This latter quality will be considered desirable
by growers of occasional specimens. On the other hand, it is not
so easily propagated as the common form and is perhaps, no hard-
ier, so that it will not supplant it for forest plantations where the
beautiful white, fine-grained wood of this species is desired,
and where the habit of sprouting from the roots is no drawback.
' ' P. alba var. Bolleana is very different from the common white

I I i !

i. WINTER TWIGS OF POPLARS. — a, b, c, d, forms of Populus grandiden-
tata ; e, P. angustifolia ; f, P. nigra, var. elegans ; g, P. balsamifera,
var. latif olia (Nolestii] ; h, P. nigra (Eugenie] ; i, P. monilifera ; j,
P. laurifolia (Certinensis) ; k, P. balsamifera, var. viminalis ; 1, P.
nigra (form known as Canescens] ; m, P. alba, var. canescens ; n, P.
alba, var. nivea ; o, P. alba.

poplar, which it resembles in foliage and bark, but its leaves are
nearly as deeply lobed as those of the common silver maple ; on
the upper side they are of a rich dark green color, while on the
lower side they have a very heavy coat of white down. Its
growth when young is nearly as upright as the L,ombardy poplar
with a tendency to a globular formed head when old. It is, how-
ever, a long lived tree even in severely dry sections in the West,
where the Lombardy poplar is worthless. It is of rather moder-
ate or slow growth. I find it much more difficult to propagate
than most other poplars, but have had fairly good success with
cuttings taken off in the fall, and well callused before planting.

216

BULLETIN 68.

in the spring, in the same manner as practiced with grape cuttings
in the West. It grafts readily on several of our common poplars
and on strong growing kinds its growth is considerably increased.
"P. alba var. argentea closely resembles the species but has
heavier down on the underside, and is rather more spreading in
habit, and is more easily propagated from cuttings."

II. THE CULTIVATED SPECIES OF POPLARS.

The following catalogue attempts to refer the nursery and horti-
cultural names of pop-
lars to their proper
botanical species, and
it includes various
notes upon the horti-
cultural values of the
different types. The
genus appears to be
much confused
amongst nurserymen,
and the perplexity has been
increased by the arrival of the
Russian varieties. In the pre-
paration of this monographic list,
I have received the greatest aid
from the collection of EHwanger &
Barry, which has been freely placed at
my disposal. The winter twigs are often
useful in distinguishing the species, and I
have therefore inserted a photograph (Fig. i)
of some of them.

GROUP I. BALSAM POPLARS, or those with
resinous-sticky more or less elongated buds.

i. Populus angfustifolia (James, Long's
Exped. i-497). YELLOW or BLACK POPLAR of
the west. Fig. 2. A pyramidal small tree with
ovate-lanceolate willow-like leaves and cylindri-
cal twigs, native from South Dakota west and south. It is spar-
ingly cultivated. It is a tree of good habit and soft clear green

2. Populus angus-
tifolia. (% nat.
size. )

THE CULTIVATED POPLARS.

217

foliage, and is worth attention in the composition of groups.
May be confounded with Populusbalsamifera, var. viminalis, which
see. The slender, cylindrical winter twigs with small buds (e, fig.i)
are very different from the heavier and angled shoots, with coarse
buds, of the other (k, fig. i).

2. Populus balsamifera (Linnaeus, Sp. PI. 1034 (1753)-
BALSAM POPLAR, TACMAHAC. Fig. 3. A tall upright tree, with
a nairow straight top, growing in woods and along streams in the
Northernmost States, and also in Northern Europe and Asia.
Leaves thick and firm,
erect, whitened beneath,
usually smaller than in
most other poplars of this
Group : in shape ovate-
lanceolate or oval, taper-
ing towards the top and
sometimes at the base,
finely and obtusely
toothed. Young branches
nearly or quite cylindri-
cal.

The native form is
occasionally seen about
farm buildings and road-
sides, where it makes a
durable and pleasant

tree ; but it is most too stiff for the pleasantest effects and too
narrow for the best shade. The dull whiteness of the under
side of the leaves affords a pleasant variety and contrast in its
foliage, and the fragrance of the resinous buds in spring is pleas-
ant to most persons. It is a desirable tree for occasional plant-
ing, but, like the Lombardy, it generally appears to best advant-
age when placed amongst other trees. It is a hardier tree than
the Lombardy, and does not run quickly to such extravagant
heights. In cultivation from Russian sources, it is known as
Nos. 1 6 and 26 Voronesh and 32 Riga. Fig. 3 shows ordinary
foliage (16 Voronesh) about half size.

The balsam poplar is probably the most variable of poplars.

j. Fopulus balsamifera (16 Voronesh.}
nat. size.}

218

BULLETIN 68.

In cultivation in this country it is represented by no less than
three well marked botanical varieties, differing from the species
and from each other in the habit of growth, shape and color of
leaves and character of twigs.

P. balsamifera variety intermedia (Loudon, Encyc. of Trees
and Shrubs, 830 (1842). P. laurifolia of American horticulturists,
not of botanists. P. Sibirica pyramidalis, of horticulturists).

Fig. 4. A com-
paratively slow
growing tree of
close upright
habit, from
Northern Eur-
ope, where it is
used as a street
tree. The leaves
are very thick
and hard, finely
nat. serrate, oval in
outline, and

prominently whitened beneath, and they are commonly rather small
for this group. Twigs hard and cylindrical. It is considered to
be a valuable tree for hot and dry interior climates ; and it also
has distinct merit for ornamental planting. It eventually becomes
a large tree. The Populus laurifolia and P. Sibirica pyramidalis
of American nurserymen are, so far as I can determine, only minor
variations of one varietal type. All these trees are amongst
the recent introductions of Russian poplars.

P. balsamifera var. viminalis, (Loudon, Encyc. 830, t. 1510.
P. viminalis, L,odd. Cat. (1836). P. Lindleyana, Booth, Rev.
Hort. 1867, 380. P. salicifolia, P. crispa, P. Dudleyi, and P.
pyramidalis suaveolens of horticulturists. Also sometimes called
P. laurifolia]. Fig. 5. A tree of only moderate and rather slen-
der growth, with a partial weeping habit when old ; native to
northern Europe. It is at once distinguished from other forms of
Populus balsamifera by its sharply angled twigs (k, fig. i), and
broad-lanceolate willow-like leaves which are finely serrate and
often crinkled-margined.

balsamifera variety intermedia,
size.

THE CULTIVATED POPLARS.

219

I am inclined to regard this as a distinct species from the balsam
poplar. If it should be elevated to specific rank, it would be
difficult to determine a correct name for it. Its first specific name

is evidently L,oddige's, Populus
viminalis, but that was only a
catalogue name and therefore
could not hold under the recent
rules of botanical nomenclature.
Populus Lindleyana was regu-
larly published in 1867, but this
name appears to have been used
by horticulturists for a form of
the cotton wood. The other
names which it bears are used only
by gardeners and nurserymen.

4. Populus balsamifera var. viminalis. (}4 nat. size.}

But however much doubt may attach to the botanical position
of this small tree, it is valuable to planters if a tree of willow-
like aspect but with more pronounced color effects and greater
size and durability is desired. It is very like the native Populus
angustifolia, which it represents in Europe, but is readily distin-
guished by its angled or furrowed stems, and less tapering and

220

BULLETIN 68.

crisped leaves which are conspicuously finely reticulated and
whitened beneath. The color of its foliage is a grayish green,
and in this respect it affords a contrast to the native species. The
native seems to be rather the better tree of the two, although the
viminalis has a more striking appearance.

P. balsamifera, var.
latifolia (London, En-
cyc. 830. P. Nolestii and
P. Wobsky of horticultur-
ists). Fig. 6. — This var-
iety includes Asiatic
forms with ovate or cord-
ate-ovate rather blunt
pointed leaves, cylin-
drical twigs (or slightly
ridged on strong shoots)
(g, fig. i ) and the gen-
eral habit of the balsam
poplar. The leaves are
usually large and thick,
shining green above and
dull white beneath, in
shape and texture some-
what like the next species (P. candicans}. The Nolestii poplar is
now sold by Eastern nurserymen as an ornamental tree. Its
strong habit and dark foliage adapt it admirably to planting
near the rear borders of grounds. The Wobsky poplar is one
of the recent Russian introductions, with somewhat the habit of
a cherry tree, and is much prized in the northwest. The Rasu-
movskoe poplar appears to be of the same type.

3. Populus candicans(Aiton, Hort. Kew. iii. 406. P. bal-
samifera, var. candicans, Gray, Manual, 2nd ed. 419. P. Ontari en-
sis and P. macrophylla of European horticulturists). BALM OF
GILEAD. Fig. on title page. — A strong-growing spreading native
tree, frequently planted, and esteemed for its vigor and hardiness
and the resinous fragrance of its large buds in spring-time. The
leaves are broad and heart-shaped, green above and veiny and rusty-
white beneath, and the leaf-stalk is usually hairy and somewhat

6. Populus balsamifera var. latifolia.
not. size. )

THE CULTIVATED POPLARS. 221

flattened. It is very different from the balsam poplar in method
of growth, as it has none of the pyramidal or spire-like tendency
of that species, but usually makes a broad and irregularly spread-
ing top. While the tree is common in cultivation, it is rare wild.
In the early days, however, it was found in very large trees in
Michigan and other western states, and was used for sawing
timber ; and isolated natural groves of it are still occasionally
seen.* The balm of gilead makes a good street tree, and is per-
haps the best of the poplars for shade. Well grown trees have
the darkest and richest foliage of any common poplar, and this
character makes the tree valuable in heavy groups about the
borders of a place. The top is liable to become open and
broken with age, however, and the tree often sprouts profusely.
It is not well adapted to smoky and dusty locations, as
it soon becomes grimmy. It was used to good purpose in the
lagoon borders of the World's Fair, where its exuberant growth
and stiff heavy leaves gave a massive effect. The illustration
upon the title-page shows a spray of the balm of gilead, one-
third natural size.

4. Populus Simonii (Carriere, Rev. Hort. 1867, 360). —
A strong strict tree from China, whence it was introduced into
France about 1861 by M. E- Simon. It is now very sparingly
planted in this country, but its merits are scarcely known. In
foliage it is much like the next species (P. laurifolia). Its leaves
differ from those of the balm of gilead in having a rounded or
tapering base and much finer teeth, but otherwise they are much
alike. The shoots are reddish brown and spotted, and deeply
grooved. Professor Craig, of the Central Experimental Farm,
Ottawa, Ontario, who has had considerable experience with the
tree, writes as follows concerning it :

' ' The tree in nursery and on the lawn is a very strong
grower, with large ovate leaves, having the characteristic five-
sided shoots of these Russian poplars. It grows very rapidly,
making a growth of from six to ten feet per annum. I have not
known it to winter kill either here or in Manitoba. It can
hardly be termed strikingly ornamental, but is useful for planting

Botanical Gazette, v. 91.

222

BULLETIN 68.

7. Populus laurifolia (or P.
Certinensis). Slow-grow-
ing shoot. ( 2/T, nat. size. )

where wind-
breaks are de-
sired quickly.
Like the Car-
olina poplar,
it has a strong
upright habit
of growth."

5. Popu-
lus laurifo-
lia (lyedebour
Icones Planta-
rum Nov.
Ross. v. 23, t.
479 (1834).
P. balsami-
f era, \&r. laur-
ifolia, Wes-
mael, D. C.
Prodr. xvi. part ii.
330. P. Certinensis, P.
Petrovski and P. Bereolensis
of American horticulturists).
CERTINENSIS POPLAR, Figs. 7, 8 ; j.
fig. i. — This Siberian species is the most
important of the recently introduced
poplars. It is a very rapid-growing and
hardy tree, with a strong central leader,
and a very heavy dense foliage. It is
the Old World representative of our
cotton wood. The foliage upon the old
wood or upon slow-growing shoots (Fig.
7) is very unlike that upon the vigorous
branches, and it is almost identical with
that of the balsam poplar, being broadly
oval, with finely serrate margins, and
whitish beneath. The twigs, also, are
cylindrical. But the strong shoots are

THE CULTIVATED POPLARS. 223

strongly angled or grooved and the foliage is much like that of
the native cottonwood but darker ; and the growth is more close
and erect. The sketch in Fig. 8 distinguishes the leaves perfectly,
however :

P. laurifolia or Certinensis P. monilifera or Cottonwood
(upper leaf). Leaves broad-ovate (lower leaf). Leaves triangu-
in outline, with a rounded or lar-ovate in outline, with a
tapering base and rather short straight or truncate base and a
point at the apex ; the margin long point at the apex ; margin
rather closely toothed, wavy ; coarsely scallop-toothed, plane;
leaf-stalk comparatively short, leaf-stalk long, much flattened
only moderately flattened, gland- beneath the blade of the leaf,
less at the top ; stipules present and commonly bearing two or
and conspicuous. Bud long, three gland-like bodies at its
Shoots slightly hairy. top; stipules absent or minute

(falling early). Bud shorter.
Shoots glabrous.

I imagine that the similarity of the Certinensis poplar and cot-
tonwood has been the means of confusing them, for I have pop-
lars under the names of P. laurifolia and Riga No. 40, which are
cottonwoods. Whether these were really introduced from Russia
after having first been introduced there from America, or whether
the confusion is a mixing in our own plantations, I am unable to
say. The Certinensis poplar is a more rugged tree than the cot-
tonwood, with healthier foliage in the presence of leaf-rust, and
its wood is said to be valuable. It is now much planted in the
Northwest, and deserves to be more widely distributed.

Its effect in the landscape is considerably unlike that of the
cottonwood. Its leaves out stand more horizontally, while those of
the cottonwood hang loosely and often vertically and therefore
give the tree top a heavier look. The terminal spray of the two
is particularly distinguishable in this regard. The leaves of Cer-
tinensis upon the strong erect shoots stand almost squarely at
right angles with the shoot, and, at some distance, therefore pre-
sent only their ruffled edges to the eye, producing a most unique
and picturesque effect. But on the whole, at least for the present,
I should consider the cottonwood the better tree for ornamental
planting in this state.

224

68.

Professor Craig, of Ottawa, writes of the species : "I have
been sending out cuttings of these so-called Russian poplars to
Manitoba and the Northwest Territories for the past four years.

The species
which has given
best satisfaction
so far is one called
Populus Certi-
nensis. It resists
drouth and cold
remarkably well,
and is looked
upon by the
settlers of the
Northwest Ter-
ritories as one of
their most valu-
able shelter and
timber trees.' '

The Certinen-
sis poplar was
used in the la-
goon plantations

at the World's Fair, but because of its rapid growth in the direction
of its leader, it made a less picturesque small tree than either the
cotton wood or balm of gilead, which were similarly planted.

8. Certinensis poplar (above) , and Cottonwood (below}.
z nal. size.

THE CULTIVATED POPLARS.

225

The name laurifolia, or "laurel-leaved," is generally applied in
this country to another plant, — Populus balsamifera, var. inter-
media. The name originated with the Russian botanist L,edebour,
and he published a good illustration of the tree he had in mind
and it is an admirable portrait of the large and crinkly leaves of
the tree which in this country goes under the name of Populus
Certinensis, — a name which, so far as I can learn, is simply a
garden or nursery name. No. 39 Riga, as I have it, is the same.
Neither am I able to distinguish
the tree grown in this country
as Populus Bereolensis. Koch*
mentions a Populus hybrida
Berolinensis as being a hybrid
between P. balsamifera and the
Italian poplar (or Lombardy),
but his tree is probably not
the same as the one grown in
this country.

6. Populus monilifera
(Aiton, Hort. Kew. iii. 406
(1789). P. angulata, Aiton,
Hort. Kew. iii. 407. P. Caro-
Imensis, Moench,
Verzeichniss
Weissenstein, 81
(1785 : Catalogue
name). P.glandu-
losa, Moench, Meth-
odus, 339 (1794)-
P. Canadensis,
Michx. f. Hist.
Arb. Am. iii. 302,
t. 12. P. Carolina
of nurserymen). 9' p°Pulusmonilifera^unu^^lform. (% nat.size.}

COTTONWOOD, CAROLINA and CANADIAN POPLAR. Fig. 8, 9; i,
fig. i . A strong growing handsome tree of large size, ranging from

Dendrologie. ii. iA, 497.

226 BULLETIN 68

western New England to Florida and the Rocky Mountains. Its
leaf characters are sufficiently outlined above (under P. laurifolia) ,
but it is variable in shape and color of leaves. Some of the forms
are fairly distinct in foliage and aspect, and they appear to be
associated with particular horticultural names, in the nurseries.
Fig. 9 shows a form with very long-pointed and round-based leaves;
but it usually bears, also, the typical triangular foliage. Some of
the most ornamental specimens of cottonwood are those which have
reddish leaf-stalks and midribs.

Taking all things into consideration, the cottonwood is prob-
ably the best of the poplars for general ornamental planting. It
grows rapidly and in almost every soil, and yet it possesses an air
of strength and durability which most of the poplars lack. Its
foliage is always bright and glossy, and the constant movement of
the broad rich green leaves gives it an air of cheeriness which few
trees possess. The tree has been much used upon the western
prairies and in western towns, much too abundantly for good
landscape effects. The rapid growth of the tree gives a feeling of
luxuriance to plantations, even when most other trees appear to
be weak or starved. The cottonwood thrives best upon rather
low lands, and yet it is generally an admirable tree upon high and
dry areas.

The so-called Carolina poplar is only a very luxuriant cultivated
form of the cottonwood. As sold by the New York nurserymen
it does not differ otherwise from the wild Popuhis monilifera of
our woods and creek borders.

There is a golden-leaved form of the cottonwood known as var-
iety Van Geertii or var. aurea. It is one of the best of yellow-
leaved trees, and generally holds its color throughout the season.
Like all trees of this unusual character, it should be used
cautiously, and the best effects are obtained when it is planted
against a group of trees so as to appear as if naturally projecting
from the other foliage.

7. Populus nigra (Linn. Sp. PI. 1034 (i753). P. Hudsonica,
Michx. f. Hist. Arb. Amer. iii. t. 10. P. beiulifolia, Pursh, Fl.
Amer. Sept. ii. 619. P. Eugenie of nurserymen). BLACK POP-
LAR, h and 1, fig. i . A European tree of medium to large size,
with leaves somewhat resembling those of the cottonwood, but

THK CULTIVATED POPLARS. 227

generally smaller and much less deeply toothed, shorter in propor-
tion to their width and often with a tapering or rounded base.
The tree usually has a pyramidal habit of growth and a dark cast
to the foliage. The leaf-stalk is flattened, so that the foliage
moves freely in the wind. It is a less lustrous tree than the cot-
tonwood and grows more slowly. Specimens were found escaped
along the Hudson by Michaux, who thought it an American
species and published it early in the century as Populus Hudsonica.
Pursh in 1814 published it again as the " birch-leaved poplar, "
Populus betulifolia , from trees found upon Lake Ontario. Although
is was found half wild in New York about a century ago, it does
not seem to have increased itself in America, for it is rarely seen,
even in cultivated ground. The tree known in the West as Pop-
ulus betulifolia is only a robust form of the European P. nigra.

The black poplar runs into many perplexing forms. The best
which I know is var. elegans {Populus elegans of nurserymen,
f, fig. i). It is a tree of pronounced strict or pyramidal habit,
but considerably broader than the Lombardy. The foliage is
small and light colored and very versatile in a breeze, with a
handsome reddish tint to the leaf-stalks and young shoots. It is
worth growing in every well kept place, especially if placed
against a planting of heavier foliage. Popidus canescens of some
American nurserymen is very like this, although it has less color
and brightness.

P. nigra, var. Italica (Du Roi, Harbkesche Baumz. ii. 141
(1772). Var. pyramidalis, Spach, Ann. Sci. Nat. 2nd ser. xv. 31
(1841). P. Italica, Moench, Verzeichness Weissenstein, 79 (1785).
P. dilatata, Aiton, Hort. Kew. iii. 406 (1789). P.fastigiata, Desf.
Hist. Arb. ii. 265 (1809). P. pyramidalis, Rozier, Diet. d'Agric.
vii. 619. P. pyramidata, P. Pannonica, P. Polonica of horticul-
turists). LOMBARDY or ITALIAN POPLAR. This tree is too
familiar to need description. It differs from the typical black
poplar (P. nigra} in its tall narrow growth, glabrous young
shoots, a confirmed habit of suckering from the root and generally
a more tapering base to the leaves. It is one of the characteristic
trees of parts of Italy, and it is from one of the Italian provinces,
Lombardy, that its common name is derived. The tree is prob-
ably native in Asia, however.

228

BULLETIN 68.

The L/ombardy poplar was much prized in this country a hun-
dred years ago. John Kenrick established a commercial nursery
of ornamental trees in Newton, Massachussetts, in 1797, and two
acres were ' ' devoted to the cultivation of the L,ombary poplar,
which was about the only ornamental tree for which there was
any demand in those days."* It is probable that very few, if
any, of the trees sold by Kenrick are still living, even in locali-
ties where the climate is not
severe ; and this is evidence
that the tree is short lived — a
fact which all careful observers
must have noticed.

A hardy type of the Lom-
bardy is grown in the North-
west. Professor Budd gives
the following account of it.f

''In the summer of 1882
Mr. Gibb and the writer were
surprised to find the Lombard y
poplar in perfect health in
central Russia, where our
locust, hon-
other trees

killed down each winter as
does the common peach in
north Iowa. Our surprise came from the fact that L,oudon in-
clined to the belief that Populus dilatata [one name for the L,om-
bardy Poplar] was native to the valley of the Po in L,ombardy,
from whence it came to England and America. But Russian bot-
anists soon assured us that its home was in the east and that its
hardiness varied like other species, and hence depended on the
region from whence it was obtained. Under the name of Populus
dilatata we imported the hardy kind from Voronesh, in central
Russia. As this is 300 miles north of the sea of Azoff, from
whence came the Russian Mennonites of Minnesota, I suspect

*Garden and Forest, i. 302:
fRural Life, Aug. 31, 1893, p. 12.

10. Lombardy Pop-
lar. (% nat. size.}

American black
ey locust and

THE CULTIVATED POPLARS. 229

that our importation is hardier than the one seen around St. Paul.
We call it the Russian Lombardy. It is a much nobler tree than
the variety from the Po valley, as its top is not so thin and spiry,
and its foliage is thicker and darker. We have not talked about
this poplar for the reason that its timber has no relative value.
Yet it fills a place in landscape gardening not taken by any other
tree."

The various merits of the Lombardy poplar — which is the most
familiar tree of the genus — have been already discussed. It has
been planted too freely, but it is gradually dying out in the east,
and time will no doubt eliminate its offensiveness in the landscape.
There is said to be a form of the Lombardy with variegated leaves,
but I hope that it will not find its way into this country. A tree
which is already over-bold would be impertinent with a painted
foliage. " Planted as it was a hundred, or even fifty years ago,
in all possible situations, without regard to its surroundings or to
the positions in which it was placed, it did more, perhaps," says
Garden and Forest, ' • than any tree which has ever been planted,
especially in some parts of Europe, to disfigure the landscape.
There is no tree, however, which can take its place, or which can
so quickly send up a tall, slender shaft to break a low or monot-
onous sky line. It became an unpleasant feature in the landscape
only when it was used without judgment and without discretion."

GROUP II. ASPENS and WHITE POPLARS, with short non-glu-
tinous often pubescent buds.

8. Populus Tremula (lyinnaeus, Sp. PI. 1034). EUROPEAN
ASPEN. Figs, n, 13. — An open-headed, light-leaved tree,
common throughout Europe, and occasionally cultivated in this
country, especially in its weeping form. Leaves small and thin
round-oval, more or less whitened beneath, especially when
young, bordered with deep and rounded incurved teeth. Leaf
buds small. The leaf-stalks are long and slender and flattened,
giving a restless motion to the foliage.

The weeping form of the European aspen is perhaps the best
weeping tree amongst the poplars. The spray is light, airy, and
fountain-like, quite unlike the more common weeping forms of
our native Populus grandidentata, which present a stiff weeping
aspect, a combination which is rarely pleasing. The lightness

230

BULLETIN 68.

of the foliage
of the Euro-
pean aspen
has been re-
tti arked by
writers from
the earliest
times. Ger-
arde, in 1597,
remarks that
the tree ' 'may
also be called
Tremble, after
the French
name, consid-
n. Populus Tremula (2/3 nat. size]. ering it is the

matter whereof womens tongues were made, (as the Poets and
some others report) which seldome cease wagging. ' '

A characteristic interest attaching to this tree is the profusion
of very long catkins which appear in earliest spring, even before
our native poplars
are in bloom. They
appear at Ithaca
late in March or the
first of April. The
staminate or male
catkins are particu-

larly pleasing, and \ ^ >^^-XM ///

planters should se-
lect that sex, if pos-
sible. The illustra-
tion on the next page
shows these inter-
esting flower-clus-
ters nearly full size.

9. Populus
grandidentata
(Michaux,Fl.Bor.-

12. Populus grandidentata.

nat. size.}

232 BULLETIN 68.

Am. ii . 243 ( 1 803) . P. Graca pendula , P. nigra pendula and Parasol
de St. Julien of nurserymen). lyARGE-TooTHED ASPEN. Fig. 12 ;
•a, b, c, d, fig. i. — This is a common native tree from Nova Scotia
to North Carolina. It is distinguished from the European aspen,
above, by much larger and thicker leaves which are bluish or
rusty- white beneath, more ovate in outline, with larger and more
spreading teeth, stouter leaf-stalks and larger leaf-buds. In its

14. Populus tremuloides (% nat. size).

normal or erect form, it is rarely cultivated, but the weeping va-
rieties, under a variety of names, are frequently seen. Most, and
perhaps all of these varieties originated in Europe, where the tree,
like the cottonwood and the common aspen, were early introduced.
The habit of the tree is too stiff and the foliage most too heavy
to make the best weeping subjects, however. One of the best of
these weeping forms is that known as Parasol de St. Julien. The
characteristic weak or zigzag winter twigs of the weeping varie-
ties of this species are shown in Fig. i . A is the form sold as
P. grandidentata pendula ; b is Parasol de St. Julien, and this
twig shows a flower-bud midway. These two forms, it will be
seen, have a stiffer or straighter habit than the two following. C
is the form sold as P. Gr&ca pendula, and d the one called P. nigra
pendula.

THE CULTIVATED POPLARS.

233

10. Populus tremuloides (Michaux, Fl. Bor.-Am. ii. 243
(1803). P. trepida, Willd. Sp. PI. iv. 803. P. Graca and
P. Atheniensis of horticulturists). COMMON ASPEN or POPPLE.
Fig. 14. — This is the commonest of the American poplars, and it
ranges from Labrador to Kentucky, New Mexico and California.
It is the species

which springs up
in recent clear-
ings. In aspect
it is much like the
European Aspen
(P. Tremula}, but
the leaves lack en-
tirely the deep teeth
of that species and
they are green on
the under side. The
catkins are also
smaller, and there
are other botanical
differences. There
are no horticultural
varieties of this
species, so far as I
kno w ; but the
plant is worthy at-
tention from plant- 75. Populus Sieboldi (% nat. size],
ers, as already indicated (page 208).

11. Populus Sieboldi (Miquel, Ann. Mus. Bot. Lugd. iii.
29. P. rotundifolia of American nurserymen). Fig. 15. A
Japanese species with foliage somewhat like the last only much
larger and whitish below. Professor Sargent says* that "this
tree is not rare in southern Yezzo, where it grows to the height of
twenty or thirty feet, springing up in considerable numbers on
dry, gravelly soil." The species is little known in this country.
It makes a tree of spreading habit, with rather dark and heavy
foliage. It appears to be hardy in western New York.

*Garden and Forest, vi. 404.

234 BULLETIN 68.

12. Populus alba (Linnaeus, Sp. PI. 1034 ( 1753)- WHITE
POPLAR, ABELE. A common European tree frequently planted
in this country. Leaves much like those of Populus grandiden-
tata, but smaller, usually thicker and more angular, the under
surface — especially early in the season — woolly white. The
straight, strong cylindrical winter shoots of this species and its

varieties, with the very
small buds, are shown at
o, n, and m, in fig. i.

The typical form of
Populus alba is less
grown here than the var-
ieties with lobed and very
white-bottomed (and
occasionally variegated)
leaves.

P. alba, var. nivea
(Wesmael, DC. Prodr.
xvi. 2d part, 324. P. nivea,
Willd. P. argentea of
nurserymen). This is
the commonest form of

white poplar in this coun-
nat. size}. . »*.••< 1,1

try. It is known by the

snow-white under surfaces of its foliage and the three or five
lobed maple-like leaves. It is far too frequent about old yards,
where its inveterate brood of suckers make it a perpetual nuisance.
It is sometimes called Silver maple, from the resemblance of its
foliage to that of the maple. The tree is so obtrusive in its char-
acter that it can rarely be used with good effect in home
grounds. As a street tree in cities it is particularly offensive for
the cottony covering of the under side of the leaves and of the
shoots holds soot and dust, and it looks repulsively dirty. It is a
misfortune that the tree were ever brought into the country, for
few people appear to know how to make a considerate use of it.

P. alba, var. canescens (Loudon, Encyc. 820). Fig. 16.
Leaves broad or nearly circular in general outline, prominently
notched but not lobed, the under surfaces and the young shoots

Populm alba var. canescens

THE CULTIVATED POPLARS.

235

very white- woolly. This tree is met with occasionally. Its hor-
ticultural value is not greatly different from that of var. nivea,

P. alba, var. Bol-
*leana (Lauche, Woch-
enschrift der Deutsche
Garten, No. 32, Aug. 10,
1878. P. B o lie ana ,
Lauche, 1. c.). BOLLES'
POPLAR. Fig. 17. A
very tall and narrow-
topped tree, with cottony
leaves rather more deeply
lobed than those of the
var. nivea. The tree
was introduced into Eu-
rope in 1875 from Turk-
estan, and it was named for Dr. C.
Bolle, an arboriculturist. The tree
bears about the same relation to Popu-
lus alba that the L,ombardy poplar
bears to Populus nigra. Its fastigiate
habit combined with the white foliage
and shoots, make it a most emphatic
tree and there is great danger of planting it too freely.

Populus alba var. Bolle-
ana (% nat. size).

INDEX TO SYNONYMS.
Populus angulata = P. monilifera.
Populus argentea = P. alba, var. nivea.
Populus Atheniensis = P. tremuloides.
Populus Bereolensis = P. laurifolia.
Populus betulifolia = P. nigra.
Populus Bolleana = P. alba, var. Bolleana.
Populus Canadensis = P. monilifera.
Populus canescens of some = P. alba, var. canescens.
Populus canescens of some = P. nigra, var.
Populus Carolina = P. monilifera.
Populus Carolinensis = P. monilifera.
Populus Certinensis = P. laurifolia.
Populus crispa == P. balsamifera, var. vimiualis.

236 BULLETIN 68.

Populus dilatata = P. nigra, var. Italica.

Populus Dudleyi = P. balsamifera, var. viminalis.

Populus elegans = P. nigra, var. elegans.

Populus Eugenie = P. nigra.

Populus fastigiata = P. nigra, var. Italica.

Populus glandulosa = P. monilifera.

Populus Grceca = P. tremuloides.

Populus Grcsca pendula = P. grandideutata.

Populus Hudsonica = P. nigra.

Populus Italica = P. nigra. var. Italica.

Populus laurijolia of some = P. balsamifera, var. intermedia.

Populus laurifolia of some = P. balsamifera, var. viminalis.

Populus Lindleyana = P. balsamifera, var. viminalis.

Populus macrophylla = P. candicans.

Populus nigra pendula = P. grandidentata.

Populus nivea = P. alba, var. nivea.

Populus Nolestii = P. balsamifera, var. latifolia.

Populus Ontariensis = P. candicans.

Populus Pannonica = P. nigra, var. Italica.

Populus Petrovski = P. laurifolia.

Populus Polonica = P. nigra, var. Italica.

Populus pyramidalis = P. nigra, var. Italica.

Populus pyramidalis suaveolens = P. balsamifera, var. viminalis.

Populus pyramidata = P. nigra, var. Italica.

Populus rotundifolia = P. Sieboldi.

Populus salicifolia = P. balsamifera, var. viminalis.

Populus Sibirica pyramidalis = P. balsamifera, var. intermedia.

Populus trepida = P. tremuloides.

Populus Van Geertii — P. monilifera.

Populus viminalis = P. balsamifera, var. viminalis.

Populus Wobsky = P. balsamifera, var. latifolia.

COMPENDIUM.

Landscape gardening is the embellishment of grounds in such
manner as to secure landscape or nature-like effects. The style
of planting, therefore, should be free and easy, devoid of all for-
malisms and unusual or forced effects. There should be broad
open spaces of greensward and heavy masses, or groups, of trees
and bushes ; and the heaviest plantings should be about the bor-
ders of the place. Scattered planting of individual trees and
bushes is fatal to good effects. Trees which are simply odd or

THE CULTIVATED POPLARS. 237

curious introduce irrelevant and jarring effects, and they should
never be made emphatic or prominent features of a place. Trees
of very unusual or striking character, as the lyombar cly and Bolle
poplars, must, likewise, be used with the greatest caution, and, •
above all, their formality" and strangeness should not be enforced
by planting them in rows, in rural places.

The poplars are examples of trees which should be used only
for secondary or incidental effects in landscape gardening, and
never to construct the body or main features of the planting.
Cheap trees produce cheap effects.

The L/ombardy poplar may be used to advantage now and then
in a group of trees to add spirit and vigor ; but it should rarely
be seen as an isolated specimen. The tree is used indiscriminately,
because it grows rapidly in all situations and because its oddity
pleases many people. It is so much abused that its legitimate
value is obscured.

The varieties of the white poplar or abele are, in general, even
less desirable than the lyOmbardy. As ordinarily planted, they
are immodest and ugly trees, especially the whitest varieties, and
their use in farm yards, country cemeteries and all small places
should be discouraged.

Poplars which should be encouraged for ornamental planting
are the common cottonwood, the common wild aspen, the normal
or erect form of the large-toothed aspen, the Certinensis poplar,
Populus elegans of the nurseries, and the European aspen.

Poplars of particular value for shelter belts and timber are the
Certinensis, cottonwood, balm of gilead, and possibly Populus
Simonii.

Species of rather heavy and dark foliage and strong growth,
and which may be used for groups or masses, are the balm of
gilead, Nolestii, and probably Populus Sieboldi and P. Simonii.

Among the species and varieties which are interesting because
of natural peculiarities and which may be used for incidental
effects or as single specimens, are Populus angustifolia, various
forms of the balsam poplar (especially the variety viminalis) , and
forms of the European black poplar.

Weeping varieties are found in several species. The best is
probably the drooping form of Populus Tremula, the European

238 BULLETIN 68.

aspen. There are good weeping forms of the large-toothed aspen
(Populus grandidentata), but they are apt to be too stiff for the
best effects fn a drooping tree. There are yellow-leaved or varie-
gated forms of some species, of which the best is the variety of
the cotton wood known as Van Geert's golden poplar.

The best single species of poplar for general planting in
New York, is probably the common cottonwood or Carolina pop-
lar (Populus monilifera). The second choice is the new Russian
species known as Populus Certinensis (properly P. laurifolia).

L,. H. BAILEY.

Bulletin 205. September, 1902.

Cornell University Agricultural Experiment Station,

ITHACA, N. Y.

BOTANICAL

SHADE TREES

By W. A. MURRILL.

PUBLISHED BY THE UNIVERSITY

ITHACA, N. Y.

A48.

OROANIZATION

OF THE CORNELL UNIVERSITY AGRICULTURAL EXPERIMENT

STATION.

BOARD OF CONTROL
THE TRUSTEES OF THE UNIVERSITY.

THE AGRICULTURAL COLLEGE AND STATION COUNCIL.

JACOB GOULD SCHURMAN, President of the University.

FRANKLIN C. CORNELL, Trustee of the University.

ISAAC P. ROBERTS, Director of the College and Experiment Station.

EMMONS L. WILLIAMS, Treasurer of the University.

LIBERTY H. BAILEY, Professor of Horticulture.

JOHN H. COMSTOCK, Professor of Entomology.

STATION AND UNIVERSITY EXTENSION STAFF,

I. P. ROBERTS, Agriculture.

G. C. CALDWELL, Chemistry.

JAMES LAW, Veterinary Science.

J. H. COMSTOCK, Entomology.

L. H. BAILEY, Horticulture, Nature-Study.

H. H. WING, Dairy Husbandry.

G. F. ATKINSON, Botany.

M. V. SLINGERLAND, Entomology.

G. W. CAVANAUGH, Chemistry.

L. A. CLINTON, Agriculture.

JOHN CRAIG, Extension Teaching.

J. W. SPENCER, Extension Work.

J. L. STONE, Extension Work.

MARY ROGERS MILLER, Nature-Study.

MRS. A. B. COMSTOCK, Nature-Study.

C. E. HUNN, Gardening.

J. A. FOORD, Dairy Husbandry.

G. W. TAILBY, Farm Foreman.

O. F. HUNZIKER, Dairy Bacteriology.

ALICE G. McCLOSKEY, Nature-Study.

J. M. VAN HOOK, Botany.

OFFICERS OF THE STATION.

I. P. ROBERTS, Director.

E. L. WILLIAMS, Treasurer.

EDWARD A. BUTLER, Clerk and Accountant.

Office of the Director, 20 Morrill Hall.

The regular bulletins of the Station are sent free to persons in the State
who request them.

CORNELL UNIVERSITY, ITHACA, N. Y., Sept. i, 1902.
THE HONORABLE COMMISSIONER OF AGRICULTURE,

ALBANY, N. Y.

Sir : — I have the honor to submit for publication under Chap-
ter 430 of the Laws of 1899 a bulletin on "Shade Trees in Cities' '
prepared under the direction of Professor G. F. Atkinson by Dr.
W. A. Murrill, who a few years ago was Assistant Cryptogamic
Botanist of this station. The work was begun by careful study
of the shade trees in Ithaca during one year, and was then con-
tinued by Dr. Murrill in some other cities in this country and in
some of the capitals of Hurope.

The matter of the bulletin is of general interest, but is of more
special interest to persons living in villages and cities. The con-
ditions of environment for trees, especially in cities, is so
different from their natural environment, that there often
result certain injuries which are difficult to determine. Mr.
Murrill has discussed these matters as well as the general care of
the shade trees, the selection of suitable varieties, and methods
of planting, pruning and protection.

There is just at present a widespread interest in the matter of
village and city improvement, and I believe that this bulletin
will contribute matter of interest and value to those who are
seeking information concerning the uses of trees in villages and
cities and the methods for their successful propagation and pro-
tection.

Very respectfully yours,

I. P. ROBERTS.

SHADE TREES.

BY WILLIAM A. MURRILL, A.M., PH.D.

One of the most obvious facts of the present day is the
gathering of agricultural populations into towns and cities.
Connected with this fact is the problem of municipal govern-
ment and the amelioration of the conditions of city life. The
object of this bulletin is to increase the growing interest in
shade trees as material aids to the healthfulness and attractive-
ness of cities and towns and to consider the principles under-
lying their selection and care. It is hoped that an intelligent
appreciation of the requirements of city trees will thus be
awakened in this country such as exists in the older cities of
Europe.

In the treatment of the subject, a discussion of the value of
shade trees with some account of the kinds found in various
cities has received first attention. The merits of different trees
in common use are next considered and lists made of those
which have been found by experience to be best fitted for street
plantings and those which have failed in greater or less degree to
fulfill the rigid requirements demanded. Lastly, the work of
planting, pruning, protecting, caring for wounds, and other
operations connected with the general care of street trees are
discussed at some length.

The illustrations are made from photographs by the author,
with the exception of those representing leaf-blight of the
maple, which were photographed by Miss A. V. Luther.

THE VALUE OF SHADE TREES IN CITIES.

The cultivation of trees in cities is beneficial in many ways.
In the first place, they add to the healthfulness of a city by cool-
ing and purifying the air. Besides cutting off the direct and
reflected rays of the sun, foliage exercises a marked effect on the
temperature by evaporating large quantities of water from its
surface, and the reduction of the temperature in this way is
greatest on dry, hot days when it is most needed. Leaves also

6 BULLETIN 205.

absorb impure and hurtful gases and manufacture the oxygen
needed by animals for respiration. Circulation of the air, due
to unequal temperature, is likewise promoted by trees properly
pruned and arranged ; while the air of basements and cellars is
rendered less humid by the removal of surplus water from the
surrounding soil through the medium of roots and foliage.

Secondly, trees add materially to the comforts of a city life. In
New York, where the streets are narrow and the houses high,
shade, may not ordinarily be considered a matter of prime impor-
tance as regards health, but it is a matter of public comfort, and
when the heat becomes intense as it has during the past two sum-
mers, it may be of great importance in protecting life. Deciduous
trees seem specially designed to shield our sidewalks from the
glare of the sun in summer and to expose them to its warmth
in winter. In many cities, especially in those of Europe, trees
are used during the summer as canopies for courts and restau-
rants, and the broad shaded sidewalks are often furnished with
lunch tables, which are much more attractive than those indoors.
Living thus in the open air not only contributes largely to com-
fort, but also to health.

In the third place, trees give pleasure. They soften the hard
lines and add attractive forms and colors to the monotony of
buildings. Their bright green foliage is eagerly watched for in
the spring and the changing colors are a constant source of pleas-
ure in autumn. The most attractive cities are those in which
well-shaded streets and beautiful parks are most abundant.
Lastly, trees add greatly to the value of property and draw men
and money to a city. The cities of the future will have wide
streets planted with trees as a matter of business. In such cities
people will remain far into the summer, when the streets and
shops of treeless cities are deserted ; and the business men will
reap the profits. During the controversy last summer over the
passage of tramcars across Unter den Linden, Emperor William
not only objected to the trams, but expressed his intention of
planting two additional rows of trees along the sidewalks on this
avenue ; and, when some one hinted that the shopkeepers might
object, he replied : " Oh, no. People prefer shade to sun in sum-
mer, therefore more people would pass through a shady street.
Consequently it would be better for the shopkeepers. "

SHADE TREES.

THE MERITS OF VARIOUS TREES DISCUSSED.

Experiments thus far made do not give a correct idea of what trees will
do in cities when properly cared for ; but certain facts have been deter-
mined with regard to many species which should be considered in making
up a list for use in cities. Without this discussion of the merits of each
tree, a list would neither be understood nor appreciated. I therefore give
below some of the points for and against the most commonly cultivated
shade trees, following their order in the list, which order is substantially
according to merit.

OAK.

So far as experiments have shown, oaks are the best shade trees for
cities. They are strong, durable, and beautiful, and have few enemies.
Owing to a popular notion that oaks grow slowly, they have heretofore been
little planted on streets, but several cities are now beginning to make use
of them. The oldest oaks are to be seen in Hamburg, where the city has
encroached upon the ancient forest. An avenue of this same species (Q.
pedunculatd] has been recently planted in Cologne, which, so far as I have
observed, is the only city in Europe that has made use of the oak for street
planting. In this country, the oldest oaks may be seen in Washington,
where the red oak and pin oak in
particular have been very success-
fully grown. Red oaks have also
been recently planted in Boston
between Franklin Park and Hunt-
ington Avenue. The best species
of oak are, probably, the red oak,
the pin oak, and the scarlet oak ;
but there are several other species
almost as good as these, though
none of quite so rapid growth as
the red oak. The white oak is
somewhat objectionable on account
of its slow growth and because its
leaves remain upon the tree after
they are dead. The number of oaks
given in the list might be much
increased. Those selected are of
various sizes and have been given

FIG. 15. — Avenue of pin oaks east

of the White House, Washington.
SYCAMORE. fo £

The sycamore is an excellent

shade producer, the leaves appearing at the proper time in this latitude and
remaining on the tree as long as could be desired, when they give place to
the persistent and graceful fruit. With a little protection it passes the

8 BULLETIN 205.

northern winters uninjured and develops rapidly into a splendid and shapely
tree large enough for the widest avenues or capable of being adapted by
pruning, to which it most readily submits, to very narrow streets. Such is
the activity of its young wood and bark that the stem is at times completely
girdled without appreciable injury, and the outer layers of its cortex are
annually sloughed off during late summer and autumn, leaving the new
layers beneath entirely free from soot and dirt accumulated during the
summer. It is partly due to this, perhaps, that it enjoys with the ailan-
thus the distinction of being best adapted to parts of cities where smoke
and dust abound.

The only serious enemy of the sycamore is a fungus which attacks its
shoots and young leaves in early summer, greatly disfiguring the tree. In
some cities of southern Europe complaint is made of the thick hairy cover-
ing which becomes detached from the young leaves and twigs and gets into
the nose and mouth producing an inflammation known as the "sycamore
cough." This tree is, however, most widely and abundantly employed in
the cities of India, Persia, and Europe, while in America it is deservedly
growing more popular as a street tree every year. In London, it is con-
sidered by many to be the only tree that will thrive in the dirt and smoke
of so large a city.

Of the two common species of sycamore, the eastern is smaller and of
closer growth than our native species, though less hardy and less beautiful
in form. It was for some time thought, also, that the eastern species was
less subject to attack by the sycamore fungus, but this is probably not the
case. In this country, the oriental sycamore is usually preferred, while in
Paris the western species is used exclusively, since it seems to conform
better to the style of pruning adopted in that city.

AILANTHUS.

The ailanthus is another importation from the orient, less common than
the oriental sycamore, and, on account of some especially objectionable
qualities, very unpopular withithe public. Some of these qualities, however,
are not serious faults and may be entirely corrected with proper care. For
example, the unpleasant odor at blossoming time is confined to the male
flowers, and trees bearing these flowers need not be cultivated. The habit
of sprouting profusely at the roots, though dangerous to pavements, ren-
ders the propagation of the ailanthus extremely easy, and also make it pos-
sible to select only the desirable trees. Those who object to the odor of the
male flowers for two or three days, however, must endure the sight of the
ugly brown fruit -clusters which often hang upon the tree throughout the
winter. A fault which cannot be remedied is the early maturity and disfig-
urement accompanying rapid growth. When young, the ailanthus is vig-
orous and shapely, if property trained, and its large leaves are green until
frost, but most of the old trees I have seen, present a very scraggly and
unsightly appearance. There are fine avenues of this tree in Paris, where it

SHADE TREES. 9

is unrivalled for vigor and general thriftiness. When these trees show
signs of failing, they will be cut down and the avenues replanted.

The qualities which make the ailanthus especially desirable as a shade
tree are its ability to grow in even the most barren soil and to thrive in
the midst of smoke and dust and other adverse surroundings peculiar to city
streets. When the question is not what tree would be the most ornamental,
but what tree would live and grow in a particular locality, then the ailan-
thus should certainly be considered.

NORWAY MAPLE.

The Norway maple appears to be the best maple we have for street use,
though most of the trees I have seen are still comparatively young. Care
must be taken to prevent its heading too low and making too dense a shade,
but this can be easily done by timely and skillful pruning. Like the sugar
maple, it suffers from dust and smoke, though not to the same extent,
while it endures other street conditions much better, as may be seen by
comparing the two species in any of our cities. After the first two or three
years it makes a strong and rapid growth, and develops into a shapely tree
well adapted to street use and free from any serious pests.

GlNKGO.

The ginkgo is a new and very promising tree from Japan. There is a
fine avenue of them in Washington and they seem to stand the winter as
far north as Boston, where several young trees have recently been planted.
At Rochester, the extremities of the lower limbs are often winter-killed,
and in northern Germany it cannot be successfully cultivated on account
of the severe cold and injury to its branches from snow. This tree is in
many ways an ideal street-tree, and is without enemies of any kind. One
must wait many years for shade, however, and the form of the tree must be
adapted to street-use by careful pruning.

The indications are that the ginkgo will make a valuable addition to our
list of shade trees ; but experiment alone will definitely determine its value.
A new tree often has many advantages in the way of soil and attention
which would work wonders if bestowed to an equal degree on some ordi-
nary and less esteemed species ; while it might be difficult to say just what
effect the vigorous conditions under which many of our city trees exist
would have upon the species newly introduced. It is to be hoped that the
ginkgo will not have to suffer all that some other trees have borne.

ASH.

The ash is a rapid grower and practically free from insects and diseases.
Its foliage does not appear so early as to exclude the sun from the soil in
spring-time. The wood is strong and valuable, but the branches are badly
deformed by the wind. As its roots lie near the surface, it is adapted to

io BULLETIN 205.

low soils. Thus far, the ash has not been very much used in cities. Of
the various species of this tree, the white ash is much the best.

HACKBERRY.

The hackberry is another of our common native trees which deserves to be
more frequently planted. It is shapely, not choice as to soil, grows rapidly,
resists drought, is easily grown from the seed and easily transplanted, and
is free from any serious diseases. Various leaf- eaters and gall insects attack
its foliage, and its branches are often disfigured by distortions attributed
to a gall-mite and a powdery mildew, but none of these troubles seriously
injure its value as a shade producer nor endanger its life. It is said to be
frequently used for shade in the west.

SWEET-GUM.

The sweet-gum develops rapidly and well in a great variety of soils and
is practically free from insects and fungus attacks. The beauty of its foli-
age in autumn more than offsets the extra care required in transplanting
and the litter caused by its fruits.

KENTUCKY COFFEE-TREE.

This tree can be grown only in rich damp soil. I have seen it very rarely
in cities, but the specimens I have observed were very handsome and I
think it deserves a trial in soils to which it is adapted.

Bui.

The merits of this most popular shade tree are so well known that I need
not record them here. It should not be planted however, to any great
extent in the large cities of the East, unless provision is made for regular
and thorough spraying and other precautions taken to hold in check its
various insect enemies, among which the leopard moth and the imported
leaf-beetle are the most destructive. The elm is adapted to wide streets
and requires deep moist soil. Its condition in many of our cities is far from
satisfactory, and its use as a street-tree is in many localities attended with
considerable risk. In towns and villages where the leaf-beetle is as yet
unknown, the elm is grown with great success.

Other species of elm are occasionally planted in our cities, but none are
equal to the American elm in general fitness for street use. The slippery
elm, for example, cannot be used on account of its mucilaginous bark, which
is relished by the small boy as a substitute for chewing gum ; and the
English elm, which does well in Berlin and Hamburg, is so greedily attacked
by the elm leaf-beetle when planted here that it is not only useless for pur-
poses of shade, but forms a centre from which this insect easily spreads to
neighboring trees of our own species. Incidentally, the English elm is
sometimes used as a trap tree in working against the elm leaf-beetle.

SILVER MAPLE.

The silver maple is a graceful tree of very rapid growth and possesses
many qualities of an ideal street tree ; but it is especially subject to injuri-

SHADE TREES.

ii

ous scales, and is often killed by borers, while its branches are liable to be
broken by the wind. There are twenty-five thousand trees of this species
in Washington, many of which bear injuries received during wind storms.
Many also have been headed back on account of their extensive growth and
are now diseased and unsightly. The silver maple endures city life very
well and, if it escapes its various enemies, develops into a fine though not
a durable tree ; and its cultivation is always attended with risk.

HORSE-CHESTNUT.

In the Spring, the horse-chestnut is an object of great beauty, but in late
summer or autumn, when the red spider and mildew have completed their
ravages, it seems unfit for
the streets of any city.
It is exceedingly tena-
cious of life ; few other
trees have suffered so
much and survived the
shock. In the deep good
soil of Bonn, the horse-
chestnut is a large and
splendid tree. In Paris,
it is abundantly and suc-
cessfully used for plant-
ing places and borders.
But on the streets of most
cities it loses its foliage
too early because of
drought and the effects of
its numerous enemies, so

aw I nil

FIG. 1 6. — A canopy of horse-chestnuts. Jardin
des Tuileries, Paris.

that it cannot be recom-
mended for general street planting.

HONEY LOCUST.

The honey locust is a fine tree with many good points, but too thorny for
city use and often killed by locust borers. The side branches also have a
troublesome way of going into the windows of houses and the pods are
somewhat objectionable.

SUGAR MAPI.E.

The sugar maple grows more slowly than the silver maple and its
branches are not subject to injury from storms. It is likewise free from
most insect pests, is easily transplanted, and capable of enduring our
severest winters. Unfortunately, however, this beautiful tree does not
thrive in cities. Its requirements as to soil and water are unusually exact-
ing and its foliage is very sensitive to dust and smoke, especially during
periods of drought. I have examined the sugar maple in many cities, but
have not found one in which it was cultivated with uniform success.

12

BULLETIN 205.

LINDEN.

The linden requires an abundance of deep rich soil and suffers much from
gas, from drought, and from insect attacks. It does fairly well in Wash-
ington, but is little planted now because of the extra care it requires as
regards soil and water. In Berlin, Frankfurt, Hamburg, and Paris, the
leaves of most varieties of linden fall prematurely on account of insect and
fungus attacks. In Philadelphia a few years ago all the large lindens were
killed by borers. A further objection to this tree is the litter made by its
blossoms and fruit.

TULIP-TREE.

The tulip-tree is too large except for the widest avenues and park borders,
where there is a quantity of rich deep soil and abundance of room. It is
likewise difficult to transplant, the branches are very brittle, and the leaves
are continually dropping throughout the season. It is, however, prac-
tically free from enemies.

BLACK LOCUST.

The black locust is a rapid grower, hardy, easily propagated and trans-
planted, and does well in poor soil.
It is successfully cultivated in
Paris, where the top is kept small
and spherical and the branches
thickly clustered. Its hard and
durable wood is beginning to be
used in Paris for paving the streets.
On the other hand, the tree is
scraggly and angular in form, its
branches brittle, its foliage short-
lived, its pods unsightly, and its
roots badly given to sprouting.
The locust borer often kills the
black locust, as well as the honey
locust, and has been known to

FIG. 17. — Black locusts near Pere
Le Chaise, Paris.

spread from these trees to certain species of oaks.

WILLOW.

The weeping willow is the only
species used on streets, and its
occurrence is rare. It grows
rapidly and when perfect makes a
fine appearance, but the wood is
tender and is often attacked by
fungi, while the tussock moth and
other leaf-eating insects frequently
destroy its foliage. The white
willow is excellent for windbreaks
and for planting along the banks
of streams, railroads, and other
embankments. Fine rows of this

FIG. 18. — Old while willows along
Cascadilla Creek, Ithaca, planted
to preserve the banks of the stream.

PI<ATE II— THE PROTECTION OF SHADE TREES.

III. — THE PROTECTION OF SHADE TREES.

DESCRIPTION OF PLATES.

PI.ATK II. The Protection of Shade Trees.

A. A tree protected with thorns.

B. Basaltic pillars about horse-chestnuts at Bonn.

C. Wicker protectors about lindens at Frankfurt a. Main.

D. Light iron guard about young maple near Prospect Park, Brooklyn.

E. Jackets of pine poles west of Brandenburger Thor, Berlin.

F. Box-guard about young red oak, Washington.

G. Wire netting on older tree, Washington.

H. Iron guard about Sycamore on Pennsylvania Avenue, Washington.
/. Two forms of iron protectors, Primrose Hill, London.

III. The Protection of Shade Tree.

A. Young sycamore in full coat of mail, consisting of support, guard,
and grill. Place de la Bastille, Paris.

B. Iron guard, about English field elm in front of the Antwerp cathe-
dral.

C. Protector and circular iron bench around sycamore on Mile End
Road, London.

A form of protector used in Frankfurt a. Main.

Young linden with wooden support, iron guard, and hexagonal

iron grill, Potsdamerstrasse, Berlin.

F. Linden with iron guard, Heidelberg.

G. Grill used alone about base of ailanthus one foot in diameter on
boulevard Montparnasse, Paris.

H. Older Sycamore with grill and guard, Place de la Bastille, Paris.

i4 BULLETIN 205.

tree may be seen in Ithaca along the streams that descend from the surround-
ing gorges and are subject to overflow from the melting of ice. It is also
used along the Thames in the western part of London to prevent erosion of
the banks during the ebb and flow of the tide.

TREES RECOMMENDED FOR GENERAL STREET PLANTINGS.

Oak, Red (Quercus rubra L. )

Pin ( " palustris Du Roi.)

Scarlet ( " coccinea Wang.)

Black ( " velutina Lam. )

Shingle ( '• imbricaria Michx. )

Willow ( " Phellos L.)
Sycamore, Oriental (Platanus orientalis L. )

American ( " occidentalis L.)
Ailanthus (Ailanthus glandulosa Desf.)
Maple, Norway (Acer platanoides L.)

TREES RECOMMENDED FOR FURTHER TRIAL.

Ginkgo (Ginkgo biloba L.)

Ash, American (Fraxinus Americana L. )

Hackberry (Celtis occidentalis L.)

Sweet Gum (Liquidambar Styraciflua L.)

Kentucky Coffee-tree (Gymnocladus dioica (L.) Koch.)

TREES WHOSE CULTIVATION ON THE STREETS OF LARGE
CITIES is ATTENDED WITH CONSIDERABLE RISK.*

Elm, American (Ulnms Americana L-.)
Maple, Silver (Acer Saccharinum L.)
Horse-chestnut (Aesculus Hippocastanum L.)
Locust, Honey (Gleditsia triacanthos L.)
Maple, Sugar (Acer Saccharum Marsh.)
Linden, American (Tilia Americana L.)
Tulip-tree (Liriodendron Tulipifera L.)
Locust, Black (Robinia pseudacacia L.)
Willow, Weeping (Salix Babylonica L.)

*Many of these trees thrive well in villages and towns. After reading the previous dis-
cussion, several excellent trees might be selected from this list for a given locality.

SHADE TREES. 15

THE PROTECTION OF SHADE TREES.

Protectors are of three kinds. The young tree needs a sup-
port to hold its trunk erect and its roots in place against the soil;
it also needs a guard to shield it from the bites of horses and
other injuries to its stem ; and it often needs a grill to prevent the
trampling of the earth about its base and the consequent injury
to its roots.

The support is usually a straight pole or joint ten to twenty
feet long made of chestnut, spruce, oak or other wood, set
firmly in the ground next to the tree either on the south
side, where it shields the stem from the sun, or in line with the
row of trees, where it is least conspicuous. The tree is attached
to its support in several places by means of iron, leather or cloth
bands padded with cushions of wool, rushes, or other soft
material to prevent abrasion. The support is removed at the
end of the third or fourth year after planting, or when the tree
is fully able to support itself.

The most primitive guard I have seen in use is a handful of
branches from a thorn bush arranged somewhat loosely about
the tree trunk. These I saw on the streets of Fontainebleau,
and I am told that they are not infrequently used along country
roads and in small villages throughout France. The next in
order of simplicity, perhaps, is the jacket of .pine poles seen
often in Berlin. These poles are fastened together by means of
wire and may easily be removed when desired. They are cheap
and efficient, and not so conspicuous as the wooden box so well
known in America. In Frankfurt, jacket guards for young
trees on retired streets are made of willow branches woven into
tall tapering basket -like forms quite unique in appearance. In
Bonn, the fine old horse-chestnut trees of Poppelsdorf Alice are
protected in situations exposed to passing vehicles with shafts of
stone planted about the tree at a little distance from its base.
These shafts. are columns of basalt brought from the north bank
of the Rhine.

In Washington and many other cities, the most common tree
guard is an elongated box made of narrow boards which encloses
the stem of the tree up to a distance of five feet or more from
the ground. The box guard is easily made and very efficient,

1 6 BULLETIN 205.

but clumsy and unsightly and affords an excellent retreat for
insects. Wire netting is a cheap and excellent protector for
trees and is now extensively used in America for the purpose.
In the case of young trees, it may be passed around the stem
and nailed to the support ; while on older trees it is usually
attached to wire nails driven into the trunk. In Washington,
the young trees are generally protected with box guards and the
older ones covered with loose wire netting. In the parks of
London, the young trees are protected with wire netting, which
is removed as the trees become older, except in the case of those
having tender bark ; and on London streets where iron guards
are used the trunk often has the additional protection of a wire
covering. Wire netting is also frequently seen in Frankfurt,
but has not yet been introduced into Paris and Berlin, and many
other cities on the continent.

The best guards are made of iron, and, although somewhat
expensive, are widely used, especially in Europe. In Paris and
London, they are generally employed ; in Frankfurt and Berlin,
they are used on the busier streets ; while in Antwerp, Bonn and
Cologne, they are being introduced with the trees recently
planted. Unless city trees are under municipal control, the
styles of iron guards are likely to be very varied and often cheap
and inefficient. In Paris, they are contracted for by weight as
well as measurement and are very strong and durable. The
Paris guard is about seven feet high, cylindrical in form, and
constructed in two parts, the iron slats being riveted to semi-cir-
cles of iron. It is fastened to the tree support at the top and to
the grill at its base, or, in the absence of the grill, it is loosely
fixed in the earth. This style of guard has been adopted in many
parts of Europe.

In America, combinations of iron rods and heavy wire netting
are frequently seen, while it is not uncommon to use rather low
iron guards and cover the trunk above the guard with ordinary
wire netting. In Frankfurt, the base of the tree is often pro-
tected by a perforated cylinder of sheet-iron set on short legs and
above this is rather stout closely woven wire.

All guards of whatever kind should be fastened securely to
the tree in such a way that no injury will result from rubbing ;

"KiSfJjl

rriTTTTrnTfTiCiiaiQoi .„_ .,„

- f^OMK* *

.. , ; -,-.«,»j«»«

'.»l*-:l

I

»

Nil

PI,ATK IV. — SOME FUNGI WHICH ATTACK SHADE TREES.

SHADE TREES. 17

and, as the trees grow larger, care should be taken to loosen and
enlarge the guards as the trees require. Neglect in this matter
has occasioned the death of quite a number of shade trees.

Grills are designed to prevent the trampling of the soil about
the base of the tree and are especially desirable on street corners
and other places where many people pass. On paved sidewalks
where the traffic is large and the amount of exposed earth at a
minimum, some such means of keeping the soil light and porous
may be considered a necessity. Grills also afford an excellent
means of watering trees during periods of drought. The con-

DESCRIPTION OF PLATE.

PIRATE IV. Some Fungi which attack Shade Trees. The Trees mentioned
are living, unless the contrary is stated.

A. White Oak on the campus of Cornell University attacked by Poly-
POTUS applanatus.

B. Polyporus hispidus on Sycamore at Wiesbaden, Germany.

C. Polyporus on black locust, Falls Church, Virginia.

D. Silver maple in Washington which has been headed back, seriously
attacked by Polyporus obtusus.

E. Polvporus sulphureus on black oak, Palisades Park, New Jersey.

F. Polyporus squamosus on English field elm, Tower of London.

G. Upper surface of same.

H. Daedalea quercina on white oak, Palisades Park, New Jersey.

/. Fruit bodies of Pleurotus ulmarius appearing on the roots of a dying
sugar maple which had been uncovered in the process of lowering
the street. Eddy Street near Cascadilla Place, Ithaca.

J. Pholiota adiposa on red maple, Palisades Park, New Jersey.

K. Polyporus Beatiei found at the base of a large black oak tree near
Blacksburg, Virginia. Related to Polyporus frondosus.

struction of the grill may be readily determined by examining
the accompanying illustrations. It is made of sections of iron
grating which fit together about the tree in a circular, rectan-
gular, or hexagonal form and are supported on wooden pegs
driven into the ground. A special form of grill is sometimes
used on very busy streets, which extends outward beneath the
sidewalk leaving considerable space about the tree, while, being
covered with pavement, it permits free use of the sidewalk up to
within a foot of the tree trunk. Grills are regularly used with
the iron guards in Paris, Berlin, and London in places where they

1 8 BULLETIN 205.

are needed . Their use in many other cities would greatly improve
the general condition of street trees.

PRUNING AND CARING FOR WOUNDS.

The natural forms of shade trees should be preserved as far as
possible ; but since trees are rarely adapted to the requirements
of a city street, more or less pruning usually becomes a necessity.
Pruning should, however, be indulged in as little as possible,
and no branch should be removed from a tree without a good
reason. The cutting of trees into various artificial shapes can-
not be justified on any reasonable ground whatsoever.

If a street tree has been properly trained in the nursery, very
little pruning is needed, and this only for the first few years
after planting, during which time the original form is preserved
by trimming the fast growing limbs, removing the crooked ones,
and shortening those that droop as they become larger and
heavier. When one must use an untrained tree, steps should be
taken at once to elevate the trunk and encourage the growth of
a straight central stem with subordinate branches. The lower
limbs of a tree should never interfere with the street lights or
with passing vehicles. In Paris, the height of the trunk is
required to be fifteen feet. The top of a tree should not be
allowed to become so dense as to exclude the sun from the soil
beneath or from buildings near-by. The foliage is also more
uniform and better developed when light and air are admitted
to the interior of a tree, and this increase in leaf surface adds
materially to its healthful effect.

It often happens that trees have been neglected until very
large. To bring them into shape requires considerable care, but
it should be undertaken if they interfere with the proper use of
the street. Trees that have been trained and are simply over-
grown can be easily brought back within bounds by thinning out
or shortening the overgrown branches. Old and failing trees
may often be stimulated to new growth by judicious pruning.
When branches are injured by accident or broken by wind or
snow, pruning becomes a necessity. It is also wise to remove
all dead branches as soon as they are discovered.

The best time for general pruning in New York State is in the

SHADE TREES.

spring before growth begins, or from the middle of February to
the middle of April. Sap-running trees are best pruned from
the middle of May to the middle of June. In case fall pruning
is preferred, trees that run
sap should be finished be-
fore the middle of October
and other trees after this
time. Injured or dead limbs
should be removed when
observed. The latter are
best seen before the leaves
fall. Dead branches are un-
sightly and dangerous to
passers-by and to children
playing beneath them, while
they also endanger the life
of the tree by carrying decay
into its trunk. A hollow
trunk often has its begin-
ning in a neglected dead
branch. Dead branches also
absorb sap and afford breed-
ing places for injurious in-
sects and fungi.

Pruning is the removal of
some branches and the
shortening of others. The

smaller the branches when cut, the better it is for the tree. While
in the nursery, branches are best removed in the bud stage and
best shortened by having their tips pinched off. If disbudding
and pinching is carefully attended to, the work of pruning in
after years is greatly lessened, while the form and vitality of the
tree is greatly improved.

When trees are planted from the nursery with a full height of
stem and with the top already formed, it is necessary only to
preserve this form by encouraging the leader and checking the
growth of ambitious side branches by cutting their tips. When
trees with low stems and unformed tops are planted, the stem

FIG. 21. — Sugar maple on South Hill,
Ithaca. A hollow trunk often has
its beginning in a neglected, dead
branch.

20

BULLETIN 205.

should be gradually elevated by cutting back the lower branches
to one-half or two-thirds their length each year for two or three
years and then removing them entirely. In case several spring
from the same point on the trunk, one or two should be cut at a

time, the others being kept
very short while the earlier
wounds are healing. In shap-
ing the top, select a leader and
make it as vigorous as possible
by trimming all strong shoots
near it and cutting back the
more vigorous side branches.
The proper form is best deter-
mined b*y the use of the den-
droscope with a dendrometer.
As the tree grows older, a few
more of the lower branches
will have to be removed and
possibly some of the upper
ones taken out to keep the top
from becoming too large or
too dense.

The removal of large bran-
ches is always attended with
a certain amount of risk and
this risk is largely increased
when more than one or two are removed during the same season ;
but if the wounds are carefully dressed and borers kept out, decay
may usually be avoided, though the loss of food cannot be replaced.
An overgrown top should usually be corrected by thinning out
some of the longer branches. This is better than heading them
back, because the effect of the latter process is to destroy the
beauty of the tree and to produce a dense objectionable cluster
of branches as well as to open a sure road for the entrance of
disease. The cut end of a large branch rarely heals over, the
adjacent parts die, and decay gradually extends to the trunk.

Certain large and vigorous trees that stand pruning particu-
larly well, such as the elms, lindens and sycamores, may best

FIG. 22. — Silver maple in Ithaca
" headed back."

SHADE TREES.

21

be headed back, each limb being cut to one-half or one-third its
length. From these cut ends new branches arise, which grow
out vigorously and uniformly, soon obliterating the more con-
spicuous effects of this style of pruning. By pruning the
healthy limbs of old and failing trees,
new vigor is imparted to them. Such
pruning should usually be accom-
panied by the improvement of the
soil. Very old elms in the L,ondon
parks have responded to this method
of treatment with remarkable vigor.
All misshapen and injured limbs
should be trimmed or entirely removed.
The sprouts that may appear about
the wounds for a few seasons after
pruning should be cut off during the
latter part of summer. Epicormic
branches induced by the entrance
of too much light into the tree are
unsightly and intercept the rising sap;
they should be removed with the
sprouts above mentioned.

The wqrk of pruning should be begun at the top of the tree
and completed at the bottom. In this way the desired form can
be better secured, and there is less danger of accident. The
men employed should be careful not to do more damage by
breaking and bruising than they do good by pruning. A rope
properly adjusted about the waist and fastened to a stout limb
above the workman is an excellent means of sustaining the
principal weight of the body while moving about through the
tree. The form and direction of the cut when removing
branches depends upon the position of the branch on the tree
and upon whether it is to be simply shortened or entirely
removed. Erect branches are shortened by cutting them at an
angle, thus preventing the undue entrance of water ; while side
branches are cut perpendicularly for the same reason. The sap-
lifter or small branch left near the cut, should always be on the
under side of the shortened branch, since if left on the top it

FIG. 23. — Branch cut even
with the trunk.

22

BULLETIN 205.

grows erect and injures the symmetry of the tree. Branches to be
removed should be cut off even with the trunk. This rule should
be invariably followed with all trees, the conifers not excepted,
even though the labor be increased five-fold. When large

branches are shortened or re-
moved, splitting and tearing
may be prevented by making
two cuts, the one beneath the
branch being made first and
followed by another above and
about a foot farther from the
trunk. A dead limb should
be cut back even with the
shoulder at its base.

The work of pruning is by
no means complete until the
wounds are carefully smoothed
down and properly dressed.
This treatment enables the
healing tissue to cover the
wounds in the shortest possi-
ble time and prevents the
decay of the wood while heal-
ing is taking place. Exposed
wood gradually loses water

and cracks are produced in which dust and moisture col-
lect and form a substratum for the growth of bacteria and
moulds. Later the spores of larger fungi enter and by develop-
ing in this mass of decayed wood become sufficiently vigorous to
attack the heart-wood and thus pass into the trunk of the tree.
If some substance is applied to the wound which will prevent
the evaporation of water and the consequent checking, decay may
be avoided. Various mixtures have been used for this purpose,
of which lead paint and coal, tar are probably the best. Both
are antiseptic as well as protective, if applied in thick layers.
In the case of large wounds, which require several years to heal,
it is well to put on a second coat after two or three years. Thin
coal tar is not suitable for this purpose as it does not prevent

FIG. 24. — Pruning properly done,
but wound not dressed.

SHADE TREES.

the evaporation of water. It may be thickened by burning in
an iron kettle. Coal tar does not injure the tissues to any appre-
ciable extent, since only the surface of the wood is cauterized by
it and there is no vital connection between this wood and the
callus which covers it. When used
on the elm, it is prevented from ad-
hering at times by water blisters pecul-
iar to this tree, In these cases, it should
be rubbed off and another coat applied.
Wounds made by accident may be
treated similarly to those made in
pruning, after the injured tissues have
been removed. Split trees should be
joined with a bolt instead of a band.
Bruised, loosened, or dead bark should
be entirely cut away, since it can never
aid in repairing the injury, but on the
contrary, encourages decay and pre-
vents the growth of new bark.
Decayed wood should be removed
and the cavity painted with coal tar,
then plugged with dry oak wood and
this smoothed on the outside even
with the trunk and coated with tar;
If the hole is too large to plug, a
board is sometimes nailed in it and

painted with tar or covered with zinc to keep borers away. At
Wiesbaden, large holes are filled with cement, probably because
cement is so abundant in that region and so easily used. I
noticed cement also used on trees in St. James' Park, London.
At Bonn, they make use of a heavy tarred felt for covering
large cavities in the trunks of trees. Sheet iron is often
employed for this purpose in America, and to a limited extent in
Europe. If the cavity is not made thoroughly antiseptic, how-
ever, the use of any of these coverings is of doubtful advan-
tage, since the exclusion of dry air and light tends rather to
encourage than to prevent decay. In case the tree is hopelessly
diseased, anything that will strengthen the trunk or conceal an

FIG. 25. — Large elm in
Jthaca covered on one
side with sheet-iron.

24 BULLETIN 205.

unsightly wound may be considered advantageous, unless it pre-
vents proper inspection of the tree and in this way becomes
dangerous.

(Walter Mulford

Bulletin 193. June, 1901.

&

Cornell University Agricultural Experiment

ITHACA, N. Y.

BOTANICAL DIVISION.

Studies of Some Shade Tree

AND

Timber Destroying Fungi.

By QEO. F. ATKINSON.

A 8.

PUBLISHED BY THE UNIVERSITY,

[THACA, N. Y.

I9OI.

ORGANIZATION.

OF THE CORNELL UNIVERSITY AGL. EXP. STA.

BOARD OF CONTROL
THE TRUSTEES OF THE UNIVERSITY.

THE AGRICULTURAL COLLEGE AND STATION COUNCIL

JACOB GOULD SCHURMAN, President of the University.

FRANKLIN C. CORNELL, Trustee of the University.

ISAAC P. ROBERTS, Director of the College and Experiment Station

EMMONS L. WILLIAMS, Treasurer of the University.

LIBERTY H. BAILEY, Professor of Horticulture.

JOHN H. COMSTOCK, Professor of Entomology.

STATION AND UNIVERSITY EXTENSION 3TAFF

I. P. ROBERTS, Agriculture.

G. C. CALDWELL, Chemistry

JAMES LAW, Veterinary Science.

J. H. COMSTOCK, Entomology.

L. H. BAILEY, Horticulture, Nature-Study.

H. H. WING, Dairy Husbandry.

G. F. ATKINSON, Botany.

M. V. SLINGERLAND, Entomology.

G. W. CAVANAUGH, Chemistry.

L. A. CLINTON, Agriculture.

B. M. DUGGAR, Botany.

JOHN CRAIG, Extension Teaching.

J. W. SPENCER, Extension Work.

J. L. STONE, Extension Work.

MARY ROGERS MILLER, Nature-Study

C. E. HUNN, Gardening.

A. R. WARD, Dairy Bacteriology.
J. A» FOORD, Dairy Husbandry.
MRS. A. B. COMSTOCK, Nature-Study.
ALICE G. McCLOSKEY, Nature-Study.

OFFICERS OF THE STATION

I. P. ROBERTS, Director.

E. L. WILLIAMS, Treasurer

EDWARD A. BUTLER, Clerk and Accountant.

Office of the Director, 20 Morrill Hall.

The regular bulletins of the Station are sent free to persons residing in
New York State who request them.

STUDIES OF SOME SHADE TREE AND
TIMBER DESTROYING FUNGI.*

BY GKO. F. ATKINSON.

A great deal of attention has been given in the past to the
study of injuries to trees caused by the microscopic fungi, but
comparatively little study has been made of the relation of the
larger fungi to the destruction of trees and timber. The most
notable work which has been accomplished in this direction
is that of Robert Hartigof Miinchen, Germany, whose contribu-
tions have appeared in the publications of the * ' Forstlische
Versuchsanstalt," in his book on the Diseases of Trees,
and in other places. During the past two years there have
appeared several excellent bulletins from the Missouri Botanical
Garden and from the U. S. Dept. of Agr., giving in detail the
results of some work by H. vonSchrenk, of Washington Uni-
versity, St. Louis.

About five years ago the writer began studying the injuries
which some of the higher fungi produce upon shade trees and
timber trees. Very little of this work has as yet been published.
Use has been made however of some of the studies and photo-
graphs accumulated in the progress of the work, in the author's
"Mushrooms', Edible, Poisonous, Etc" (1900), and in other
places ; while a short article was published on ' ' Some Wood
Destroying Fungi," as special report No. 9 in the Geological
Survey of Louisiana, Feb. 1900. It has been my plan as far as
possible to select one or more individual cases and then endeavor
to trace the history of the relation of the fungus and its host.
This would include a study of the present conditions, and an
effort to determine, by examination, the time in the past when
the fungus entered, the mode of its entrance and progress, as
well as the probable cause of the wound which provided the
ranee court for the tree enemy. In a number of cases these

Pi

e principal facts in this paper were presented before the Mass. Hort.
Boston, Mar. 1901.

200

BULLETIN 193.

have been worked out quite satisfactorily. The studies have
been made in New York State, chiefly at Ithaca and in the
forests of the Adirondack Mountains.

A word might be said at the outset in regard to the relation of
these wood destroying fungi to others, as well as in regard to
their structure. They are among the higher fungi and belong
to the larger group known as the Hymenomycetes to which the
mushroom also belongs. In fact it is becoming customary with

some to apply the
term " mushroom "
to all of the Hymen-
omycetes. However
widely these plants
differ in their form
and structure they all
agree in the general
character of their
fruiting surface. It
forms a thin layer or
"membrane," cover-
ing definite parts of
the fruit body, and
consisting of innum-
e r a b 1 e club-shaped
cells standing side by
side. Each one of
these club-shaped
cells is called a basid-
ium, and usually
bears four spores.

There are several
large families, or
orders in the group.
I will call attention to
a very* 'few in each
family in order to show more definitely the form and general
character of the species examined here. In one of these families
the fruit body is often spread over the surface of the wood in

56. — Polyporus borealis. Fruit bodies growing
from wound on hemlock spruce.

SHADE TREK AND TIMBER DESTROYING FUNGI. 201

thin smooth patches, or some forms are shelving, when the under-
side is smooth and is the fruiting surface. These belong to the
family Thelephoracea . A few of its members are very destructive
to wood and some are parasites on trees. In another family the
members are known as "coral fungi," or " fairy clubs " a large
number of them belonging to the well known genus Clavaria,
from which the family name Clavariacea is derived. The fruit-
ing surface is distributed all over the surface of the plant. To
a third family, Hydnacea belong the "hedgehog fungi," with
the fruiting surface on spines, a few species of which are well
known. A number of
the members of the two
last named families
grow on wood, but often
appear in late stages of
decay. A few species
like Hydnum septentri-
onale on maple, and H.
schiedermayeri on apple,
are destructive.

The two largest fami-
lies are known as the
Agaricacece, to which the
common mushroom be-
longs, and the Polypor-
ace&. In the latter the
fruiting surface is in the
form of a honey-comb 57. — Polyporus borealis, section of fruit body.
on the under side of the

fruit body. It is to this last named family that the species belong
which are treated of here.

The gross characters, those which are quite easily made out
without the aid of a mieroscope, are chiefly the ones presented
here, since a detailed account of microscopic structures and
changes brought about in the wood by the action of the
ingus, are rather too technical for full treatment in this paper.

202

193.
POLYPORUS BOREAUS.

Polyporus borealis occurs on pines, spruces, the hemlock, etc.,
and is widely distributed over the North Temperate Zone. It
occurs on living or dead trees. It is a "wound" parasite,
entering through broken branches, through wounds caused by
impact of falling timber, or where the cambium has been
scorched by fire. The fruit bodies are entirely white. When

: * :M^££M^K<-& Vv 'I'^j*1;

-:

58. — Polyporus borealis, Hymenium with sinuous pores.

old or dry they often take on a pale yellowish tinge. They are
shelving, the cap attached directly to the tree, broad at the free
end and tapering somewhat in a wedge-shaped manner toward
the base. They are rarely single, and sometimes scattered over
the trunk. They usually occur, several close together overlap-
ping in an imbricated fashion, and joined at the base in a common
trunk at the exit from the tree.

SHADE TREE AND TIMBER DESTROYING FUNGI. 203

The fruit bodies are rather soft and spongy. They last only
for the season. They are 10 to 20 cm. (4 to 8 inches) long by 6
to 15 cm. broad. They form larger masses where several are
joined. The upper surface is rough with coarse tufts of
mycelium giving it a very shaggy or sodden appearance. The
honey-combed surface is below. The hymenium consists of
quite regular pores with rounded openings in some specimens,
or irregular, elongated and
sinuous pores in other
specimens, resembling the
pores of Dadalea. But
they are evenly sunk in
the substance of the cap
and therefore lack the
essential character of that
genus. The walls of the
pores are thin, and the
edges often irregular and
jagged.

There are two cases of
its occurrence on living
coniferous trees which I
have carefully studied.
One case is that of a
hemlock spruce ( Tsuga
canadensis} . The other
is that of a red spruce
(Picea rubra) , the common
timber spruce of the
Adirondack region.

The hemlock spruce
was a large tree, 60 cm.

(2 ft.) in diameter, on a steep slope in one of the deep gorges
(Fall Creek) at Ithaca, N. Y.

This example was observed in the autumn of 1899. The
fruit body of the fungus was situated at a large wound on the
trunk near the base. It consisted of several caps closely joined
at their origin from the trunk of the tree. This is well shown

59- — Polyporus borealis, Hymenium with
rounded pores.

204 BULLETIN 193.

in the several photographs. A section through the entire fruit
body (Fig. 57) shows the radiating lines formed by the general
direction of the mycelium in the caps from their common origin
in the tree trunk.

One of the photographs gives us a clue to the manner in which
the mycelium of the fungus entered this particular tree. The
log, lying in the foreground, close by the trunk of the affected
tree, tells the tale. This tree in its descent, years ago, struck
the slightly projecting base of the standing hemlock, and
knocked off a large area of the bark and cambium, or growing
region, at this spot. This wound was too large and the tissues

60. —Polyporus borealis. Disintegration of wood.

too much bruised to permit rapid healing over. It offered there-
fore a sure infection court through which the mycelium entered.

This also shows that the healing has been going on for a long
time from the margin of the wound. But the wound is so large,
it is yet far from being healed. Had it later healed over, it
could not, of course, save the tree from destruction because the
wound parasite was already permanently established in the
interior, or heart, wood. Thus the wound which gave entrance
to the fungus mycelium also offers a place for its exit in the
formation of the fruit body.

From the time the mycelium entered the trunk at this wound,
which must have been from 25 to 40 years ago, the mycelium
gradually made its way into the heart, and from there grew
downward into the roots and upward through the heart to the

SHADE TREE AND TIMBER DESTROYING FUNGI. 205

top of the tree. Its presence on the roots was determined by
the occurrence of the fruit bodies from
a few places on exposed parts of the
large roots, while external evidence of
its having reached the top of the tree
was shown by a number of dead limbs
in the top, some of which had fallen.
Evidence of its having reached the top
was also found on cutting down the tree,
and taking out sections at different points
in the trunk. Here was found an abund-
ance of mycelium and the heart wood
was in an advanced stage of decay.

The mycelium advances in certain
definite directions in the wood of the
tree. This is probably due to the struc-
ture of the wood. It grows in three
different directions : parallel with the
axis of the tree trunk, i. <?. up and down ;
radially, from the center toward the
periphery ; and tangentially. At one
stage of development the mycelium may
be very profuse and abundant. It then
is present in the form of cords or strands
which lie radially or tangentially in the
channels which have been dissolved by
the action of the fungus ferment on the
wood. These strands lie quite close
together and are parallel. After being
developed in considerable abundance
the strands of mycelium largely dis-
appear having burrowed open channels 6i.—Red spruce affected
and furrows through the wood in the with Polyporus borealis.
radial and tangential directions.

Shrinkage of the wood occurs at the same time because of the
disappearance of a considerable content of the water and of the
wood substance. This shrinking results in checking the wood
into numerous minute cuboidal blocks, marked off primarily by

206

BULLETIN 193.

the position, and solvent action, of the mycelium. This becomes
more pronounced if the wood dries, if the tree is cut or if blocks

of the wood are cut from the trunk
and allowed to dry. In the early
infection of the wood, and the
early stages in the advance of the
mycelium, before the larger strands
have become established, the open-
ings made by the mycelium are
very minute. They take the same
directions as the larger openings.
In fact the mycelium, instead of
making a general attack upon the
tissues, begins its advance at cer-
tain regularly separated points,
and then extends along in parallel
lines. If the wood is cut out at
this early stage, one can see these
minute perforations thickly scat-
tered over the exposed surface.
Sometimes, even in this early
stage, shrinkage of the wood will
have taken place. If not very
marked when freshly cut from the
wood, the shrinkage of the wood
on drying, marks it off in a beauti-
ful manner, by fine lines and holes
into cuboidal areas.

In many of these cases of the
heart rot of trees, after the heart
wood is well affected, the mycelium
being well established and vigor-
ous, gradually encroaches on the
cambium or living area beneath
the bark. In this way, many of
the branches in the top of the tree

62. — Effect on wood of red
spruce by the mycelium of
Polyporus borealis.

die, and in some cases later the cambium of the trunk may be
so destroyed as to kill the tree outright.

SHADE TREE AND TIMBER 'DESTROYING FUNGI. 207

The red spruce example, in the Adirondack woods, was a tree
of handsome proportions near Pearcefield Falls, in the Raquette
River, left by the lumberman a few years prior to 1896, the
season when I observed the tree. At some distance there was
no indication that the tree was diseased and I enquired of my
guide, who had at one time some experience in cutting timber,
why the tree was left. ' That tree ain't no good," he replied.
As we ap-
proached
nearer, he
said, "don't
you see the
gum running
from all the
knot holes?"
This he ex-
plained was
regarded as a
sure sign of
" heart rot."
Furthermore
the tree was
"checked"
on one side,
the crack be-
ing quite
large and
extending for
some d i s-

tance. The check was probably caused by a wrench given the
weakened tree during a heavy wind. There was no other exter-
nal evidence that the tree was diseased, and to satisfy myself that
the tree suffered from ' ' heart rot, ' ' I had my guide cut out a
few blocks of the wood from the trunk. Two inches beneath the
bark, the wood was found in a '" dozed " condition. The heart
was not in a very advanced stage of decay though the area was
very extensive. The mycelium visible to the eye was very
scanty. Still the wood showed numerous fine perforations, and

63. — Fruit bodies of Polyporus borealis, showing
shaggy cap.

208

BULLETIN 193.

as some shrinkage had taken place, it presented the very fine
divisions into minute blocks described above. I then searched
more carefully for some fruit form of the fungus and found at
the ground level, buried under leaves, a fruit body of the Polyp-
orus borealis between two buttresses of the base of the trunk.
The tree was not felled, and -consequently there was no oppor-
tunity of ascertaining the special mode of infection in this case.

POLYPORUS SULPHUREUS.

The sulphur polyporus has a very wide distribution and occurs

on a great variety of broad
leaved trees as well as on certain
of the conifers. It is known on
the apple, walnut, butternut,
locust, oak, ash, pine, hemlock
spruce, and other trees. It
occurs on living trees, the fruit
bodies growing from knot holes
or wounds from the mycelium in
the heart of the tree ; or the
fruit bodies arise from portions
of the trunk killed by the fun-
gus. It is also a very common
fungus on dead and decaying
logs, stumps and roots.

The plant is easily recognized
by the yellowish color of the caps
which are of the shelving form,
sometimes scattered, but more
often closely overlapping.
Sometimes the caps are so
closely crowded as to form a large tubercle 20 to 25 cm. or more
in diameter. The upper surface of the cap is a bright orange red,
while the lower surface, the honey-combed fruit surface, is sul-
phur yellow. The fruit bodies are rather soft, the color soon
fades, they are quickly attacked by insects, or decay after sev-
eral weeks. They are short lived therefore, while the mycelium
within the trunk is perennial, or at least lives from year to year
without an annual infection.

64. — Polyporus sulphureus.
Large tubercular fruit body
on oak.

SHADK TRKK AND TIMBER DESTROYING FUNGI. 209

OAK TREE KILLED BY POLYPORUS SULPHUREUS.

A scarlet oak tree (Quercus cocdnea} growing near the grounds

of Cornell University
was under observa-
tion for several years.
The tree was stand-
ing on the edge of the
Fall Creek gorge, not
far from the F i s k
McGraw mansion and
opposite the present
electric power plant
of the Ithaca Street
Railway . It was first
observed in 1897. At
this time the mycel-
ium of the sulphur

65. — Polyporus sulphureus. Scattered fruit , , ,

bodies on living oak. polyporus had ad-

vanced so far from

the heart wood into the sap wood, that the latter, as well as the
cambium layer, on one side
of the trunk near the base,
had been killed. This gave an
opportunity for the exit of the
fungus and the formation of
the fruit bodies on the out-
side. Fig. 65 is from a pho-
tograph taken in 1897. They
are fine specimens, but are
much more scattered than is
usual with this species. The
fruit bodies appeared during
the succeeding seasons of 1898

and 1899. During the latter

66. — " Punk " in cracks on oak log.
season the tree died from the

injuries of the mycelium in its advance on the cambium or living
portion of the trunk. It was felled, and several sections cut
out from the trunk for observation.

210

BULLETIN 193.

The decay of the heart wood had reached an advanced stage so
that it was quite soft, and the moisture content was much less
than in healthy trees. The lessening of the water content of the
heart wood during the growth and spread of the mycelium caused
a shrinkage in the wood. This produced several radial checks
into which the mycelium had grown forming sheets of pure
mycelium, sometimes called "punk."

POLYPORUS SULPHUREUS IMPRISONED IN A WHITE OAK.

A white oak tree about 40 years old was growing quite close
by the side of a larger tree on the grounds of Cornell University.

The tree leaned
slightly away from
the larger one and
there was a one
sided development
of the branches
induced by strong-
er illumination
from that side.

' The tree was
felled in order to
see if there was a
correspo n d i n g
asymmetry in 4he
annual growth of

the trunk which

67.— Section of living oak with imprisoned . ,, , „:*-«.

mycelium of the sulphur polyporus. might be mamtest

in the excentric

position of the annual rings. Before cutting the tree down there
was no evidence that it was diseased. The trunk to all external
appearance was sound. There were no broken limbs, no wounds,
visible. On cutting the trunk into sections to study the annual
rings, the heart wood through a large part of the trunk pre-
sented unmistakable evidences of partial decay following many
of the annual rings and along by the medullary rays. The
wood in these areas was being disorganized by the mycelium,
and the latter forming the incipient stages of punk.

SHADE TREE AND TIMBER DESTROYING FUNGI. 211

The case'was an interesting one since the question arose as to
how the fungus, now completely imprisoned, gained entrance to
the trunk. The butt was sound so the fungus could not have
entered through the roots.
Perhaps it entered at a large
branch broken a number of
years ago and now completely
healed over.

All of the sections showed
more or less decay at the
central core of the heart wood
where some of the wood was
so badly decayed in some sec-
tions as to break out or crum-
ble from the friction of the
saw. One of the sections not
far from the base of the trunk
presented on the lower end,
and near the periphery, a cir-
cular black area, resembling
the dead remnant of a branch
which might have broken off
years ago, and healed over.
On the surface of the same
side of this section was a prom-
inent enlargement in the
trunk, resulting from the
healing process. But the evi-
dence of a wound here was
largely obliterated because the
old bark had formed over the
surface. There was only a
minute opening, very obscure
which was not completely healed over.

By examining successive sections of the trunk below this one
it was observed that this black "core" representing the broken
portion of the young tree gradually came to lie exactly in the
central core of the trunk. This indicates quite clearly that the

68. — Section of oak showing
decay at center.

212

BULLETIN 193.

injury occurred to the tree in the sapling stage, and that the
sapling was broken off instead of one of the branches. One of
the upper branches
then became the
' ' leader ' ' and in course
of time the broken end
of the sapling was en-
closed by the healing
tissue.

This section of the
trunk was then sawed
through lengthwise and
in such a direction as to
split the core of the
dead sapling radially
from the center of the
new trunk. A view of
one-half of this section
is shown in Fig. 70. It
shows the origin of the
branch which became

69. — Section of oak showing dead sapling
stage near center.

the new " leader" of the tree; as well as the large and irregular
__^ end of the broken sap-
ling covered over by
the healing tissue.

The cross section
shows that this in-
jury occurred more
than 30 years ago,
very near 'the time
that Cornell Univer-
sity was founded.
Some accident, the
cause of which we can-

70. — Section of oak showing slivered end of not now determine,
broken sapling. befell thig Uee in Ug

youth and the sapling was broken off, while one of the topmost
remaining branches in time replaced the main trunk.

SHADE TREE AND TIMBER DESTROYING FUNGI. 213

An injury resulting from this kind of fractures leaves a long
and slivered end some distance from the point where healing
takes place. It must be a number of years then before the
healing process can advance so far as to cover the fracture. In

this instance over thirty years
elapsed. The broken and
slivered end of the sapling offered
the most favorable lodgement
place for spores of fungi, and
for the accumulation of detritis
resulting from the constant
weathering of the exposed sur-
face. In these places moisture
is also conserved. The condi-
tions presented are favorable for
the germination of the spores
and entrance of the mycelial
threads. No more favorable
infection court could be pro-
vided whereby the fungus is
enabled to enter the heart wood.

From this point of infection the mycelium spreads both ways
down the old trunk of the sapling, and upward in the branch

71 . — Polyporus igniarius, tongue
form of fruit body on beech.

72. — Polyporus igniarius. Hoof form on beech.

which forms the newly established leader. The progress of the
fungus is comparatively slow, and the disorganization of the
wood accompanies it. The slow growth of the mycelium is

214 BULLETIN 193.

probably due to several causes, the resistance which it meets
from the wood, the action of tannic acids in the heart wood, as
well as to the small amount of air in the interior of the tree.
When sections of the trunk were cut, and piled together, the
mycelium at the cut surfaces grew very rapidly. The mycelium
here had access to air, and the moisture was conserved by the
cut surfaces being in contact. In this way it was easy to demon-
strate the presence of the mycelium in parts of the wood which

73. — Polyporus igniarius,from maple.

to the eye appeared sound. The mycelium grew out from the
wood into the moist air, along the concentric annual rings, and
the medullary rays, so that within 24 hours the location of the
mycelium at these points was plainly demonstrated and photo-
graphs taken at this time marked the location of the mycelium
in the infected areas. In several days time, however, the
mycelium spread out between the cut surface forming thin sheets
of " punk."

POLYPORUS IGNIARIUS.

This species occurs on broad leaved trees. It is known on the
apple, oak, alder, beech, birch, maple and other species. The
fruit bodies are hoof-shaped, very hard, almost stony, the upper
surface black, while the lower surface, the fruiting surface, is
brownish. The upper surface is marked by concentric furrows

SHADE TREE AND TIMBER DESTROYING FUNGI. 215

and ridges which mark off the annual layers. The fungus is
thus perennial.

It is very generally distributed through hardwood forests. It
is especially abundant in certain hardwoods in the Adirondacks.
In some sections a large percentage of the beech, birch and
maple is affected. A quantity of the wood of affected trees was
collected both at Childwood, St. Lawrence Co., in 1896, and at
Clearwater, Herkimer Co., in 1898. At the latter place, the
second flag station north of Fulton Chain, on the N. Y. C. R. R.,
there were excellent opportunities for studying it on the maple,

and for determining

the conditions which
favor the entrance of
the fungus into the
heart of the tree.
Since the mycelium
cannot enter through
the living cambium of
the tree, an "infec-
tion court " must first
be provided. ' These
infection areas are
provided in a variety
of ways, in general
their origin being the
same as for other tim-
ber destroying fungi
which enter through
wounds.

The conditions pre-
vailing in a large portion of the mixed forests of the Adirondack
region are such that a very common point for entrance is provided
by the falling of the lower limbs. In the mixed forests the
spruces :and pines tower so far above the hardwood as to cut off
much of the light. The hardwoods are thus so shaded that the
area of foliage is considerably lessened, many of the trees having
few limbs, and then bearing few leaves compared with trees in
the open, or even in a hardwood forest where all the trees have
an equal chance for light.

74. — Section of fruit body of Polyporus
igniarius.

216

BULLETIN 193,

A maple tree about 20 cin. (eight inches) in diameter in the
mixed forest at Clearwater had been affected by the Polyporus
igniarius for a number of years. The fruit body was several
years old, of a triangular shelving form, and 15 cm. broad.
Several entire sections of the trunk, one of them bearing the
fruit body of the fungus, were collected and shipped to Ithaca.
Cross sections of the tree present a very characteristic and
often beautiful marking of the wood due to the different stages
of decay and the coloration of the wood. The more advanced
stages of decay lie at the centre, the less advanced ones toward
the periphery. The sound wood at the periphery is limited

from the decayed area
toward the centre by
a broad and irregular
discolored area. The
discolored area is of a
light brown color, and
this is farther sharply
defined from the pale
yellowish white area
outlined by a narrow
black line. The more
advanced stages of
decay, in this maple
tree advanced toward
the periphery in
separated columns,
showing on cross sec-
tion a radiating or
digitate figure. The
radiations or "fin-
gers," alternate with
dark areas which ex-
tend inward from the

75. — Section nf maple tree showing effect of
mycelium of Polyporus igniarius.

periphery as shown in the photograph. Sometimes this figure
is quite regular around a portion of the margin, while other
portions are very irregular. The decay of the wood seems to
proceed in waves from the centre toward the periphery, so that

SHADE TREE AND TIMBER DESTROYING FUNGI. 217

there appear several different stages. The outer one is marked
by the dark discolored area, the next is pale yellowish white, the
wood being quite soft, and an older and more advanced area at
the centre of the heart. These different stages in the process
of decay from the centre to the periphery are usually limited by
the black line, which is bordered by a more or less well defined
corona of color darker than the area upon which it is advancing.

76.— Young trunk of maple nearly killed by Polyporus
igniarius.

In many cases these areas of decay progress very irregularly,
and the figure becomes complicated and confused, especially in
the later stages of the decay of a tree, so that dark lines extend
very irregularly.

An examination of several maple trees bearing the Polyporus
igniarius gave evidence that the peculiar discoloration of the
wood, accompanied the mycelium of this species of fungus, and
might perhaps be sufficient to identify the species even where no
fruit form of the fungus was present. An examination of the

218

BULLETIN 193.

trunks of the beech bearing the Polyporus igniarius collected^at
Childwood, N.Y., in 1896, presented the same characteristic col-
oration and marking. The maple is said by some lumberman to
be troubled by a disease which they term " black heart." It
would be interesting to know if the coloration produced in the
heart by the action of the mycelium of Polyporus igniarius is
identical with this "black heart " disease.

It now becomes a matter of interest to determine the mode of
entrance of the mycelium of this fungus into the tree. The
fruit bodies were found to be situated at wounds. These
wounds, or places of exit for the fruit form of the fungus, were
" knot " holes formed by the dying away of the lower limbs, and
the failure of the healing tissue to close the wound thus formed.
The fruit form can make its exit through quite a small opening,

77. — Effect of mycelium of Polyporus igniarius on
wood of beech.

and usually does, growing to larger dimensions outside as it
ages. The first year's growth of the fruit form may then be
quite small, as in Fig. 79 where it is but a small protuberance i
to 2 cm. in diameter and showing no fruiting surface. This
often increases in size each year, slowly, until 4 to 5 cm. in
diameter, when it may increase more rapidly and each year form
a new fruiting surface beneath.

The young fruit form shown in the photograph is on a trunk
of a maple 10 cm. in diameter. This was the only evidence
that the tree was diseased, all the other wounds at fallen limbs

SHADE TREE AND TIMBER DESTROYING FUNGI. 219

having healed over. A section of the
trunk shows that the heart rot had be-
gun. It is in the first stages of
the disease and confined to a limited
area, that directly at the centre of the
heart. There is present here only the
discolored area which is characteristic of
the other and younger area in older
stages of the disease, described above.
It is quite likely that the fungus enters
at these slow healing wounds where the
lower limbs have fallen, and that in some
cases the wounds might entirely heal over
and imprison the mycelium before the
fruit bodies had an opportunity to form.
That there was abundant opportunity for
the mycelium of the fungus to enter at
these wounds is shown by the evidence
of a large proportion of the young maple
trees in the mixed forest at Clearwater.
I have already called attention to the
deep shade in the spruce woods where the
tall spruces overtop the broad leaved
trees, and of the effect which this shade
has in checking foliage development on
the younger maples. Even on the young
and middle aged maples there are com-
paratively few branches and these near
the top of the tree, the lower branches
having died and dropped off. The same
can be said of the beeches, birches and
other broad leaved trees. Even on these
topmost branches there are compara-
tively few leaves, because of the low
light reaction. This means then that a
comparatively small amount of the car-
bohydrates necessary in the formation

78.— Ulcers on trunk of
mafile.

22O

BULLETIN 193.

of cell walls and woody tissue is manufactured. Consequently
growth and the formation of wood goes on slowly. This inter-
feres in a striking way with the healing processes needed to cover
up the wounds caused by the falling limbs.

When there is an abundance of foliage and light, carbohy-
drates are formed in sufficient abundance to heal at a rapid rate.
The healing tissue is firmer than the normal wood, and working

from within and close to the
branch, soon heals over and
excludes the myceliutn of the
timber destroying fungi. On
the other hand, when there
are few leaves and a small
amount of starch is formed
the healing process goes on
slowly, and before the open-
ing caused by the falling limb
can be closed, the portion of
the branch exposed undergoes
first weathering, and later the
mycelium lays hold and enters,
reaching the heart of the tree
before the barrier of healing
tissue is formed. From obser-
vations during several seasons
it seems that this is a very
common mode of entrance for
the timber destroying fungi in the broad leaved trees.

A number of cases observed at Clearwater offer striking exam-
ples of the slowness with which the healing process goes on at
branch wounds. The healing tissue formed slowly and did not
close up against the base of the branch because of the small per-
centage of newly formed plant substance. Then for a series of
years the healing would cease and an area around the knot
would die back. Then for another series of years the healing
would begin and advance over a portion of this dead area, when
another period would intervene during which a still greater
area would die back. In this way large and ugly, open ulcers

79. — Very young p-uit body of Poly -
porus igniartus forming at a
branch wound.

SHADE TREE AND TIMBER DESTROYING FUNGI. 221

are formed, in which the wood within is exposed. This condi-
tion is shown in photographs from young maples. On a number
of these examples there were no fungus fruit bodies, but a sec-
tion of the trunk shows all the character of the heart rot caused
by the mycelium of Polyporus igniarius.

The Polyporus igniarius has been known for a long time to
inhabit fruit trees, especially the apple, peach, etc., under certain
conditions. During August, 1900, I observed an apple tree by the

80. — Fruit bodies of Polyporus pinicola on red spruce.

roadside a few miles south of Cortland, N. Y., with fruit bodies
of this polyporuson it. A number of years ago the tree had
been pruned, by cutting several large limbs near the trunk, and
others out some distance from the trunk. The tree was probably
diseased at that time, and perhaps these limbs were dead or
dying. This may have led to their amputation.

In all cases the fruit bodies of the fungus were formed at
these cut surfaces, there being no other place of exit. The tree
was probably seriously wounded when young, and the mycelium
entering had spread all through the heart of the trunk and

222

BULLETIN 193.

branches, but was unable to form the fruit bodies until the larger
limbs were pruned.

Several of the branches of this apple, bearing fruit bodies,
were taken for examination. The character of the heart rot is
in all essential respects the same as that observed in the maple
and beech.

POLYPORUS PINICOLA.

The pine destroying polyporus is widely distributed in the
United States and other north temperate regions. It occurs on

81. — Section of fruit body of Polyporus pinicola, shozving strata of tubes.

various conifers, on the pines, spruces, balsams, larches, etc.

The fruit bodies are shelving, hard and firm, though not so
hard as those of Polyporus igniarius. They are perennial and
therefore single specimens increase in size from year to year,
usually becoming broader below and of course thicker from each
annual accretion layer.

The fruit body is marked on the upper surface by prominent
concentric ridges and furrows. The marginal ridge is the one
representing the latest year's growth The color of the fruit
body is from dark brown to nearly black at the base, varying to
a reddish brown near the margin. The marginal zone represent-

SHADE TREE AND TIMBER DESTROYING FUNGI. 223

ing the latest growth varies in color according to the time of col-
lection. When the marginal zone is young it is whitish or
yellowish in color, becoming reddish yellow or red later in the
season and having then a shining polished surface. The under
surface is yellowish white, and on bruising, the yellow color is
often more distinct. The pores of the under surface are just visi-
ble to the naked eye. On sectioning the fruit body the annual
layers seem quite distinct.

82. — Section of fruit body of Poly poms app/anatus, showing tube strata,

The size and distinctness of these concentric elevations or
zones on the upper surface of the fruit body vary according to
the rapidity of growth. Where the growth is rapid the zones
are large and prominent on the fruit body, increasing rapidly in
size each year. One fine specimen collected on a hemlock spruce
in the vicinity of Ithaca is 40 cm. broad by 25 cm. long, and is
only six or eight years old, there being apparently two imperfect
zones which may represent years of very slow and imperfect
growth. Of the six annual marginal accretions which are very
prominent the measurements are as follows: First, 4 cm.;
second, 6cm.; third, 3 cm.; fourth, 2.5 cm.; fifth, 3.5 cm.;
sixth,. 4 cm. The usual size of the annual zone is from 2 to 3

224 BULLETIN 193.

cm. Sometimes, however, they are much smaller, from 4 to 8
mm., and then they are not very prominent. In such cases
however, the color character of the different zones and the char-
acter of the under surface make it possible to distinguish the
plant from others.

83. — Fruit bodies of Trametes abietis, shelving form.

In this and some other forms where the zones are not very
distinct it is occasionally difficult to separate the species from
forms of Polyporus applanatus. In the latter species the tube
surface is sometimes yellowish. In the fresh condition, if a
bruise or scratch occurs on the tube surface of Polyporus applan-
atus the exposed parts at once change to a dark brown or black-
ish color. When dry, however, this test will not yield the

SHADE TREE AND TIMBER DESTROYING FUNGI. 225

results desired, but section the plant through the middle perpen-

dicularly and compare the color and structure of the tube strata.

In Polyporus applanatus the strata are deeper and very clearly

differentiated. They are also

of a dark gray, or hair-brown

color, while the tube strata of

Polyporus pinicola are whitish

or yellowish-brown, and while

clearly differentiated are not

so distinctly so as in Polyporus

applanatus.

The fruit bodies of Poly-
porus pinicola are sometimes
found on the trunks of living
trees but much more fre-
quently they do not appear
until the tree is dead. They
are quite common on dead
standing trunks and stumps
and on fallen logs. They
continue to grow after 'the
tree is dead and in quite an
advanced stage of decay.

In wood which is in quite
an advanced stage of decay,
extensive sheets of mycelium
forming "punk" are often
in the crevices formed by the
checking of the wood. These
sheets of punk are very simi-
lar to those formed by Poly-
porus sulphureus in deciduous 84. — "Dozed " place in butt oj red

°f *"*'

as well as in coniferous trees.

In the large number of cases

in which I have found these sheets of punk in rotten

logs or decaying tree trunks of conifers in the Adirondack

mountains, I have not found any fruit bodies of the Polypovus

sulphureus. Since these sheets of punk found in conifers'are

226

BULLETIN 193.

usually ascribed to this species, I searched diligently for speci-
mens on the trees. In no case in the Adirondacks have I yet
found Polyporus sulphureus on conifers, although it probably
does occur on them. This suggested that the sheets of punk in
the conifers examined were connected with Polyporus pinicola,
and many examples were studied in an endeavor to trace the

connection of the sheets of punk in
the trunk with the fruit bodies on
the exterior.

The direct connection was diffi-
cult to trace although in most
examples it was not difficult to trace
the punk through the log radially
to the bark, but at this point in
splitting the bark radially the direct
connection of the punk was not seen.
The most favorable examples for
study were those in which the fruit
body was just originating as a tuber-
cle 4 to 6 cm. in thickness on the
outside of the bark. In splitting
several of these from the tree a cir-
cular patch of the punk was found
on the inner surface of the bark
and looked very much as if the
mycelium issuing from the tree and
connected with the fruit body had
been riveted on the inner surface of
the bark, but on splitting such
structures radially no evidence of
the connection of the bark with the fruiting body was presented.
However, on splitting the bark tangentially successive sheets of
punk were found between the inner sheet and the fruit body.
These sheets at certain points extended obliquely and connected
so that they formed a zig-zag connection. The firm layers of
the bark prevented the direct radial exit of the mycelium, but
by working in a zig-zag fashion between the bark layers it was
enabled to make its exit. Having discovered this, it then became

85. — Dead stub oj red spruce
iv here the mycelium entered.

SHADE TREE AND TIMBER DESTROYING FUNGI. 227

an easy matter to trace the connection of the punk in the log
with the fruiting body in all cases.

POLYPORUS PINICOLA ON BROAD-LEAVED TREES.

I have not found any record of Poly poms pinicola on broad -
leaved trees. I have, however, found it on three different
species in the Adirondack Mountains, on the beech {Fagusferru-
gined], the birch (Betula lento), and the maple (Acer saccharum).

TRAMETES ABIETIS.

This plant is common on spruces and balsams. It is a shelving
form, and much smaller than the species of polyporus just

86. — Fruit body of Tramates abietis spread out on surface of -limb.

described. The caps stand out from the wood 2 to 5 cm., are
somewhat triangular in side view, and broader than long. The
base is usually spread out where it is attached to the tree, and
often the entire plant is spread over the surface of the wood.
In this case no shelf form is developed. The upper surface of
the shelf is marked by concentric furrows and ridges, and is
more or less velvety or hairy. When young the fruit bodies are
tawny in color, but in age they become a darker brown, especially
above, while the fruiting surface is a yellowish brown.

228

BULLETIN 193.

TRA.METES ABIETIS ON THE RED SPRUCE.

An interesting example of a red spruce (Picea rubra) was
examined during September, 1898 in the Adirondack mountains.
This was near Nehasena, Herkimer Co., on the tract owned by
Dr. Seward Webb. Through the courtesy of Prof. C. S Graves,
who then had the supervision of the forestry operations on this
tract, I had the privilege of following the lumberman for two
days to inspect trees, or portions of trees, which were discarded
after they had been felled.

In this particular case the entire tree had been discarded,
although two logs had been
cut from the trunk. On
approaching the tree I first
came upon the stump, and
searched here for some evi-
dence of the reason for reject-
ing the timber. Near the
periphery of the stump, in
the older sap wood near its
junction with the heart wood
was a crescent shaped area in
cross section about 3 cm. broad
and 15 cm. long. This was
distinctly marked off from the
surrounding portion by the
coarser fractures of the
wood by the cross cut saw used
in felling the tree. This indicated that the wood was here
slightly l< dozed." The remainder of the stump was sound.
This small area showing such a slight alteration in the wood
probably would not have been considered objectionable.

On examining the cut made for the first log, 16 feet above,
the entire heart proved to be badly decayed. A large part of
the sap wood was also invaded, and the cambium was being
encroached upon. There remained only a thick shell of living
and unaffected tissue underneath the bark. The heart wood
was so soft that the fracture from the saw teeth was irregular,
roughly cut and partially ' ' ironed ' ' down by friction from the

87.-

-Pockets of decayed tissue in
limb of red spruce.

SHADE TREE AND TIMBER DESTROYING FUNGI. 229

saw blade. Still another log above this one had been cut off by
the woodmen in the hope that the heart would be sound, and
that a good log could be obtained near the top. This cut, how-
ever, pre-
sented a con-
dition similar
to the fi r s t
one, the heart
and sap wood
were badly
decayed. This
condition was
sufficient t o
cause the
abandonment
of the entire
tree. There
were no evi-
dences on the
trunk, below
the branches,
of the fruit
bodies of any
fungus, nor
of any injury
which might
have afforded 88' — Pockets of decayed tissue in trunk of red spruce.

an entrance for the fungus. The cut ends of timber were so badly
roughed up by the saw that no structural characters in the
diseased timber which might aid in the determination of the
species of fungus could be seen. The next step was to deter-
mine the fungus and the place where it entered the tree.

Since the decay at the stump was so slight, and the diseased
area so small in comparison with the extensive injuries farther
up in the trunk it was quite evident the fungus had not entered
from below. Upon searching in the top of the fallen tree, it
was found that the " leader " of the tree when about 5 cm. (2
inches) in diameter had been broken off, possibly by a falling

230 BULLETIN 193.

tree, 30 or 40 years ago. This leader, as a dead, decorticated
object still projected 15 to 20 cm. above the point where the
healing process was going on (Fig. 85). One of the upper
branches at this point had become the leader.

This old fracture of the main trunk years ago very probably
provided an opportunity for the entrance of the fungus. Most
conifers are provided with a quantity of free resin in the young
branches or shoots, or the growing portion of the trunk. As is
well known this resin flows freely from fresh wounds, and often
continues for some time from old ones. The presence of this

89. — Cross section of red spruce showing pockets from end view.

resin and its free exudation from wounds is nature's most effect-
ive method of blocking the way to the entrance of timber
destroying fungi in the conifers. When the wound is small, or
the broken branch or shoot is young, the amount of resin forms
an effectual barrier against the entrance of this class of fungi.
Where the wound is larger, or the shoot is older, the process of
healing over requires many years, and the older portions of the
wood do not yield so great an amount of free resin.

The broken shoot in this example was 5 cm. (2 inches) in
diameter. Healing began 20 to 30 cm. below the broken end.
After 30 or 40 years the dead prong still projected 15 to 20 cm.
above the healing surface, and probably never would have healed

SHADK TREK AND TIMBER DESTROYING FUNGI. 231

over. During this long time the fungus mycelium had an oppor-
tunity to enter, travel down the heart wood of the trunk and
reach the butt. It is interesting to observe that while the fun-
gus mycelium gained entrance through the broken area of the
leader in the top of the tree, and traveled downward, the greater
injury to the trunk was some distance below. This is probably
due to the greater amount of free resin in the younger portion
of the trunk above. While the mycelium traveled downward
through this, it did not spread rapidly here nor bring about
such a complete
disintegra t i o n of
the tissue. Sec-
tions of the trunk
just below the
point where the
fungus entered,
and for some dis-
tance below, show
the heart wood is
finer and harder
though invaded by
the mycelium. The
wood is also very
m uch stained,
brown irregular
areas often marked
off by black lines,
or divided up into smaller areas by black lines. The mycelium
also traveled upward in the newly established leader of the tree.
From the trunk it had invaded many of the branches in the
same way. As is usual in such cases a number of the branches
had been killed. These dead branches then yielded readily to
the disintegrating action of the fungus.

On a few of the limbs fruit bodies of Tramctes abietis were
found. A branch bearing a fruit body and broken at this point
shows the gross structural characters of the wood affected by the
mycelium of this species. This is shown in the photograph.
At one stage in the decay of the wood there are numerous areas

90. — Rotten section front rotted log of red spruce.

232

BULLETIN 193.

in which the process of disintegration is localized, or where it
proceeds much more rapidly than in the surrounding wood.
These isolated centres are quite evenly
distributed. The wood is broken down
completely, and largely consumed, leaving
a partial skeleton, or nearly all of it hav-
ing disappeared. The remnant, as well as
a thin layer of the bordering tissue, is
bleached and white. It is thus in strong
contrast with the reddish color of the sur-
rounding wood where the decay has been
checked or has proceeded more slowly.
This rapid local disintegration, then, forms
numerous small ' ' pockets ' ' distributed
through the affected wood at a certain stage
in the progress of the disease. They are
plainly visible because of the bleached
tissue.

These pockets are a characteristic feat-
ure in one stage of the heart rot of the
spruce from the mycelium of Trametes
abietis. If they are found in the heart
wood of the trunk of this individual
spruce it would be quite conclusive evi-
dence that the heart rot here was caused
by this fungus, and that the infection
having occurred at the broken trunk in the
top of the tree many years ago had gradu-
ally spread down the trunk to the base
and out into numerous branches, some of
which have been killed as result. Sections
of the trunk of this tree were cut out at
different places and shipped to Ithaca for
study.

On splitting sections of the trunk cut
from the discarded logs, these characteristic
pockets were found to be present, and Fig.
88 is from a photograph of a small block.

91.— Badly pruned oak
tree.

These occur in the

SHADE TREE AND TIMBER DESTROYING FUNGI. 233

portions of the trunk where decay has made considerable ^pro-
gress, the entire heart being invaded, and the fungus encroach-
ing on the " sap " wood. When cut with the cross-cut saw, or
even with a finer saw, the ends of the blocks
do not show the pockets, since the soft wood is
so readily fractured by the teeth of the saw.
But when the end of a block is planed off smooth
the pockets in transection are quite distinctly
brought to view. They are shown in the photo-
graph. From a side and end view shown in the
photographs the pockets are seen to be oblong
in side view and cylindrical in cross section.
They are 2 to 3 mm. broad and 4 to 6 mm. long.
In the younger portions of the trunk, some dis-
tance above the size where logs were cut, and
below the point of
entrance of the fungus,
and thus nearer it, the
pockets were not yet
formed. This is prob-
ably due to the fact that
while the mycelium first
penetrated the heart
wood here, the latter
being younger was more
resistant, and the pro-
cess of disintegration
proceeded less rapidly.
The pockets appearing
on certain of the branches
is accounted for by the
fact that these branches
had been killed for some
time, and were consequently in a less
condition.

The formation of pockets by the rapid disintegration of the
tissues at many centers recalls the ' ' peckiness ' ' of cypress wood
caused by the mycelium of a fungus yet unknown. The pockets

92. — Result of bad

/runing of
i c k or y, the
limbs have rot-
ted out allowing
entrance of fun-
gus mycelium.

93. — Proper way to prune,
wounds healing up
properly.

resistant

234

193.

in the cypress wood are much larger, however, and the structural
character of the affected wood is quite different. In the case of
the cypress trunks affected with this disease known as ' ' pecki-
ness," it is believed that the fungus, while developing at the
centres, excretes an enzyme or "ferment," which permeates
the surrounding wood and acts as an antiseptic which prevents
the further disintegration. It is possible that this is to some
extent the case in the formation of the
pockets in the spruce timber, that is, that
the wood intervening between the centers
of rapid disintegration, becomes permeated
with an enzyme excreted by the mycelium
which renders it immune for a time, or at
least retards the disintegration of the wood.
But if this is the case, the effect of the
antiseptic is not lasting. In the case of
fallen logs affected by the Trametes abietis
the decay continues until all parts of the
wood are in a much decayed condition.
Still, in such logs, it is quite evident that
the progress of the disintegration has been
intermittent, certain centres having first
decayed, and in time spreading from these
pockets to surrounding areas until all the
wood is brought under complete contribu-
tion to the mycelium. In such decayed
spruce wood, there are further evidences
that the decay has spread from numer-
ous centers which have been extended until
they finally met. This is shown in the
varying coloration of the wood, and especi-
ally by black boundary or limiting lines.
(Fig. 90.)

It is evident from these and similar studies
that there is no cure for the diseases caused by wound parasites
after once the fungus has entered through the wound into the
interior of the tree. For a few years there may be no apparent
injury but with the lapse of time the tree becomes badly injured

94. — Shade tree used as a
hitching post.

SHADE TREE AND TIMBER DESTROYING FUNGI. 235

if not destroyed. The trees may live for years, or even a cen-
tury or more with the fungus inside still growing. They may
be so weakened that they are broken down or uprooted during
strong winds. Shade trees may be rendered unsightly, and
lacking in density of foliage. Fruit trees may be rendered less
fruitful if not ultimately killed. Timber trees in a very few
years may be so injured as to be worthless for the market.

In their relation to forestry these studies emphasize the
desirability of careful and economical methods in the felling of
timber to protect the young stand from injury, in the supply of
light to the forest floor, and in the protection from fire. For
while many forest fires may not be so severe as to kill the trees
outright the fire often scorches exposed roots, or the base of
trunks, where the leaves are thick, or by a dead and dry log or
stump, thus affording an entrance for these wound parasites.

In the handling of fruit and shade trees there should be the
greatest care from the nursery stock to the fruiting tree to pre-
vent wounds. In pruning operations especially should there be
care in pruning smooth and close to the trunk, followed by the
use of some antiseptic wash, or lead paint.

THE FOLLOWING BULLETINS ARK AVAILABLE FOR DISTRIBUTION TO

PERSONS LIVING IN NEW YORK STATE.

40 Removing Tassels from Corn, 9 pp.

71 Apricot Growing inWestern New York,

26pp.

72 The Cultivation of Orchards, 22 pp.

74 Impressions of the Peach Industry in

N. Y., 28 pp.
76 Some Grape Troubles in Western N.Y.

116 pp.

79 Varieties of Strawberry Leaf Blight, 26

pp.

80 The Quince in Western N. Y., 27 pp.
87 Dwarf Lima Beans, 24 pp.

93 Cigar-Case-Bearer, 20 pp.
97 Entomogenous Fungi, 42 pp.

101 The Spraying of Trees and the Canker

Worm, 24 pp.

102 General Observations in Care of Fruit

Trees, 26 pp,

103 Soil Depletion in Respect to the Care

of Fruit Trees, 21 pp.
109 Geological History of the Chautauqua

Grape Belt, 36 pp.

Extension Work in Horticulture, 42 pp
Spraying Calendar.
Dwarf Apples, 31 pp.

no
114
116
117
119
1 20

Fruit Brevities, 50 pp.
Texture of the Soil, 8 pp.

Moisture of the Soil and Its Conser-
vation, 24 pp.

121 Suggestions for Planting Shrubbery.

122 Second Report upon Extension Work

in Horticulture, 36 pp.

123 Green Fruit Worms, 1 7 pp.

124 The Pistol-Case-Bearer in Western

New York, 18 pp.

126 The Currant-Stem Girdler and the
Raspberry-Cane Maggot, 22 pp.

129 How to Conduct Field Experiments

with Fertilizers, u pp.

130 Potato Culture, 15 pp.

131 Notes upon Plums for Western New

York, 31 pp.

134 Strawberries under Glass, 10 pp.

135 Forage Crops, 28 pp.

136 Chrysanthemums, 24 pp.

137 Agricultural Extension Work, sketch

of its Origin and Progress, n pp.

138. Studies and Illustrations of Mush-

rooms : I. 32 pp.

139. Third Report upon Japanese Plums

16 pp.

140 Second Report on Potato Culture, 24 pp.

141 Powdered Soap as a Cause of Death

Among Swill-Fed Hogs.

142 The Codling-Moth.

143 Sugar Beet Investigations, 88 pp.

144 Suggestions on Spraying and on the

San Jose Scale.

145 Some Important Pear Diseases.

146 Fourth Report of Progress on Exten-

sion Work, 26pp.

147 Fourth Report upon Chrysanthemums,

36pp.

148 Quince Curculio, 26 pp.

149 Some Spraying Mixtures.

150 Tuberculosis in Cattle and its Control.

151 Gravity or Dilution Separators.

152 Studies in Milk Secretion,

153 Impressions of Fruit-Growing Indus-

tries.

154 Table for Computing Rations for

Farm Animals.

155 Second Report on the San Jose Scale.

156 Third Report on Potato Culture.

157 Grape-vine Flea-beetle.

158 Source of Gas and Taint Producing

Bacteria in Cheese Curd.

159 An Effort to Help the Farmer.

160 Hints on Rural School Grounds.

161 Annual Flowers.

162 The Period of Gestation in Cows.

163 Three Important Fungous Diseases ol

the Sugar Beet.

164 Peach Leaf-Curl.

165 Ropiness in Milk and Cream.

166 Sugar Beet Investigations for 1898.

167 The Construction of the Stave Silo.

168 Studies and Illustrations of Mush-

rooms ; II.

169 Studies in Milk Secretion.

170 Tent Caterpillars.

171 Concerning Patents on Gravity or

Dilution Separators.

172. The Cherry Fruit-Fly :- A New Cherry

Pest.

173. The Relation of Food to Milk- Fat.

174. The Problem of Impoverished Lands.

175. Fourth Report on Japanese Plums.

176. The Peach-Tree Borer.

177. Spraying Notes.

178. The Invasion of the Udder by Bacteria.

179. Field Experiments with Fertilizers.

180. The Prevention of Peach-Leaf Curl.

181. Pollination in Orchards.

182. Sugar Beet Investigations for 1899.

Bulletins Issued Since the Close of the Fiscal Year, June 30, 1900.

183. Sugar Beet Pulp as a Food for Cows.

184. The Grape Root-Worm ; New Grape Pest in New York.

185. The Common European Praying Mantis ; A New Beneficial Insect

in America.

186. The Sterile Fungus Rhizoctonia.

187. The Palmer Worm.

188. Spray Calendar.

189. Oswego Strawberries.

i9g. Three Unusual Strawberry Pests and a Greenhouse Pest.

191. Tillage Experiments with Potatoes.

192. Further Experiments against the Peach Tree Borer.

193. Shade Tree and Timber Destroying Fungi.

STATE OF NEW YORK
DEPARTMENT OF AGRICULTURE

RAYMOND A. PEARSON, Commissioner

EMERGENCY BULLETIN

ON THE

BLISTER RUST OF PINES

AND THE

EUROPEAN CURRANT RUST

HORTICULTURAL BULLETIN No. 2

Prepared by

GEORGE G. ATWOOD

July, 1909

ALBANY

J. B. LYON COMPANY, STATE PRINTERS
1909

BLISTER RUST OF PINES (Peridermium stroll)
EUROPEAN CURRANT RUST (Cronartium ribcola)

/—""Blister rust of pine has recently been found in this and other
near-by States on a few white pine seedlings imported from Ger-
many. Acting under authority of the State law and with the
co-operation of all persons interested, this Department hopes to
eradicate the disease promptly. The white pine (Pinus strobus),
native to America is recognized as one of the most beautiful of
trees and its value for timber is enormous. Judging by the experi-
ence of other countries where the blister rust disease prevails, it
may be said that the American white pine is in grave danger so
long as this disease exists in our country. Some foreign nursery-
men have abandoned the business of white pine growing because
of the losses on this account.

The recently increased interest in the subject of reforesting
astareas_pf our lands not adapted for farming purposes has led
to a demand for coniferous seedlings far in excess of the supply.
Millions of these seedlings have been imported from nurseries in
other countries where the climatic conditions and cheap labor favor
such production. A large proportion of these trees are grown
from seeds of the pine which are annually exported from the
United States. Young trees are suitable for forest planting when
from two to three years old.

The disease has been found upon a number of the three-year
seedlings imported in the spring of 1909. Unfortunately the
presence of the fungus is not apparent at or before planting time.
Tt develops sufficiently in June to be identified by the spore forma-
tions. The prominent character of the disease quickly disappears
and by the first of July it can hardly be found even by the closest
expert examination. The same appearances recur the following
year. It is known that when the fungus once becomes fixed in a
pine tree it will remain until finally the tissues of the tree are so
involved as to kill it. Affected three-year seedlings are likely to
die the first year of planting, but this is not an invariable rule.
Two-year seedlings may be infected and not develop spores until
they are three years old. Such seedlings imported from abroad
should be very carefully inspected next May and June and all
suspicious plants removed and burned as described below. The
stages of growth of this fungus are complex and not generally
understood. It does not spend the full cycle of its life on the in-

3

dividual tree which it infects and it does not spread directly from
one pine tree to another.

The spores scatter in the early spring months and take lodgment
on Ribes (currants and gooseberries). In the month of Septem-
ber an orange red rust appears on the under side of the leaves of
the Ribes. The spores of this fungus then spread to pine trees
where they develop in eighteen months as the blister rust of the
pine. The fungus form found on Ribes (Cronartium ribicola)
was first described fifty years ago and named by Dietrich. The
form of fungus found on pine trees was first described and named
by Klebahn in 1887 as a distinct species and by him named Peri-
dermium strobi. Subsequently, through inoculation experiments,
it was conclusively proven that Cronartium ribicola on the cur-
rant and Peridermium strobi on the pine are not separate species
but only different stages of one and the same fungus. With this
knowledge it is self evident that, as the disease cannot spread from
one pine tree to another and can only be spread from the pine to
the currant and from the currant to the pine, the disease can be
suppressed if not entirely eradicated by burning all the infected
pines and all the Ribes growing in proximity. If, therefore, we
have suspected disease in valuable pines it is best to destroy the
less valuable Ribes before they become diseased or show the fungi
on their foliage. This procedure is specially urged where the pine
plantings are important and where the Ribes are growing wild
and are actually worthless.

Once before — in 1006 — this disease appeared in New York
State. It was found by Prof. F. C. Stewart upon the grounds of
the New York State Experiment Station at Geneva and prompt
and radical treatment was resorted to, which is believed to have
completely eradicated the disease. The report upon this outbreak
and procedure was issued as Technical Bulletin No. 2 of the New
York Agricultural Experiment Station, and owing to the fact that
the edition is exhausted a large part of this bulletin is reprinted
as an appendix to this circular.

BLISTER RUST or WHITE PIXE.

Prof. Stewart has given careful attention to the present appear-
ance of the disease and the following statement was prepared by
him:

" Blister rust is a fungus disease affecting the trunks and

4

branches of white pine trees. Trees of all ages are attacked.
Small trees are often killed outright. On large trees many of the
branches die. The disease is especially troublesome in nurseries.
In Holland and northwestern Germany it has caused much dam-
age. Diseased trees are recognized by the conspicuous yellow spore
masses which break through the bark about June 1. The affected
bark or branch is usually abnormally enlarged at the point of
attack.

" In another stage of its life cycle the blister rust fungus at-
tacks plants of the Kibes group (currants and gooseberries both
wild and cultivated), producing a conspicuous red rust on the
under surface of the leaves during August and September.
Neither currants nor gooseberries are seriously injured.

" Fortunately, the disease cannot spread from one pine tree to
another. It must first go from pines to Ribes (in May or June)
and from Ribes back to pines (in August or September). In the
trunks of pine trees the fungus is perennial, but on Ribes it affects
only the leaves and cannot live over winter. In order that the
disease may spread it is necessary to have both white pines and
Ribes growing near together. Accordingly the best method of pro-
tecting pine trees against the disease consists in destroying all
currants and gooseberries in the vicinity."

When the blister rust was found a few weeks ago in one of the
Lake Clear nurseries of the State of New York, and reported by
Mr. C. R. Pettis, a State forester, after identification had been
verified by Dr. Perley Spaulding of the United States Department
of Agriculture, Forest, Fish and Game Commissioner Whipple
immediately called a conference of foresters and other officials of
this and adjacent States, including also officials of the National
Department of Agriculture. The following persons attended:

Mr. W. 0. Filley, State Forester, New Haven, Conn.
A. F. Hawes, State Forester, Burlington, Vt.
Alfred Gaskill, State Forester, Trenton, N. J.
F. W. Rane, State Forester, Boston, Mass.
€. R. Pettis, State Forester, Albany, N. Y.
Dr. Perley Spaulding, Bureau of Plant Industry, Washing-
ton, D. C.

Dr. Harvey Metcalf, Bureau of Plant Industry, Washington,D.C.
Raphael Zon, Forest Service, Washington, D. C.
Hon. R. A. Pearson, Commissioner of Agriculture, Albany, N. Y.

5

Hon. J. 8. Whipple, Forest, Fish and Game Commissioner,
Albany, N. Y.

Austin Gary, Superintendent of State Forests, Albany, N. Y.

G. G. Atwood, Chief Nursery Inspector, Department of Agri-
culture, State of New York.

Prof. J. W. Tourney, Yale Forestry School, New Haven Conn.

H. R. Bristol, Superintendent of Woodlots, D. & H. Railroad,
Plattsburg, N. Y.

Hon. George Aiken, Forest Commissioner, Woodstock, Vt.

John Foley, Assistant Forester, Pennsylvania Railroad Co.,
Philadelphia, Pa.

Prof. F. C. Stewart, State Agricultural Experiment Station,
Geneva, N. Y.

S. N. Spring, Consulting Forester, New Haven, Conn.

Prof. C. C. Curtis, Professor of Botany, Columbia University.

Hon. R. P. Bass, Forest Commissioner, Peterboro, N. H.

It was unanimously agreed that no serious damage should result
if prompt and efficient action is taken at once by all of the States
concerned to eradicate all danger caused by the appearance of the
disease at the few places where it has been found. Several of the
northeastern states besides New York have imported large quanti-
ties of white pine seedlings for reforesting lands and a consider-
able number of private parties have also made importations. Thus
far the trees positively known to be affected are believed to have
come from a single nursery in Germany. Every effort is being
made to trace all shipments from the nursery concerned, as well
as to carefully examine other foreign importations. Valuable
assistance is being given by the Federal Department of Agricul-
ture. All persons in this State who have planted pine tree seed-
lings are urged to carefully study and carry out the recommenda-
tions below and to communicate with the Commissioner of Agri-
culture at once if suspicious symptoms are found. To succeed
quickly in preventing danger from the disease it will be necessary
to have the co-operation of all concerned. Operations have been
started in other states. It is a disease that cannot be discovered
until it has developed for a year and for that reason any inspec-
tion at the docks on arrival of trees could not be effectual.

At a conference held in the office of the Commissioner of Agri-
culture, attended by experts of the Department of Agriculture,
Forest, Fish and Game Commission and the State Experiment

6

Station, the following procedure in connection with the eradica-
tion of blister rust was formulated and is now recommended to all
concerned.

1. Procure as complete a list as possible of every place at which
white pine stock has gone during the past two years. It is desired
that this list include all stock imported from Germany and France.

2. Inspect all such premises and destroy all Ribes plants, wild
and cultivated, within 100 yards from such trees, and even a fur-
ther distance where practicable. The Ribes plants should be
pulled up or cut off in such a manner as to prevent sprouting.
For example, the skunk currant should be pulled up because it
spreads from under-ground stems, while gooseberries and culti-
vated currants difficult to pull may be cut off below ground. Burn
all such plants found as explained under No. 4.

3. Keep close tab on cultivated currants and gooseberries in all
districts of the State where suspicious pines are located, and after
July 15 keep closer watch than heretofore on currants and goose-
berries throughout the State.

4. Destroy by burning all infected or suspicious pine or Ribes
plants. This is especially important in 1909 for Ribes may be
expected to show signs of the disease if at all after July 15.

The plants are to be burned where they are found or at a place
to which they are carried in bags made of closely woven heavy
cloth such as canvas or factory, and all such bags should be thor-
oughly boiled or otherwise sterilized at the conclusion of each day's
work.

5. Suspicious pine plantings to be thoroughly inspected during
the last two weeks in May and the first week in June (between
May 10 and June 10 probably safe). This is very important in
1910 and should be repeated in 1911, the thoroughness in that
year depending largely on 1910 findings.

The Forest, Fish and Game Commission is assisting in carrying
out the above and has assisted further by sending out the follow-
ing letter to those who have secured white pine seedlings through

the commission:

" STATE OF A EW I ORK,

" FOREST, FISH AND GAME COMMISSION,

" ALBANY, July 10, 190'9.

" DEAR SIR, — The demand for trees, for reforesting purposes,
was so great last spring, that we were unable to supply a. suffi-

cient quantity from our nurseries and a large number were im-
ported from Germany. We very much regret to say that we have
since found some of the white pines were affected with ( blister
rust/ although they were carefully inspected. This disease may,
if allowed to take its course, become very serious, but if prompt
action is taken it can be prevented from spreading to other trees
or establishing itself.

" The disease is peculiar in that it lives for a time on white pine,
then on currant or gooseberry bushes, and then back on the pine
again, but never goes direct from pine to pine. The spores of this
disease are borne on the pine in May, while they are not produced
on. the currants or gooseberries until August.

"A campaign has been carefully outlined by the State Depart-
ment of Agriculture and the Forest, Fish and Game Commission
in order to control the disease. The method is simply to remove
and burn all currants and gooseberries, both wild and cultivated,
either within a plantation or on a strip not less than three hundred
feet wide around the outside of all such plantations. However,
in order to have this method effective such gooseberries and cur-
rants must be destroyed before August first.

" Owing to the large number of places to which this stock has
been sent and the short space of time in which the work ought to
be done it is necessary we ask your co-operation in this matter.
Therefore, will you begin at once to remove and burn all currant
and gooseberry bushes, both wild and cultivated, either within
or on a strip not less than three hundred feet wide all around
your plantation?

" Hoping at an early date, to hear that we will receive your as-
sistance in this matter, I remain,

u Very truly yours,
(Signed) "C. R. Pettis,

State Forester."

All nurserymen, horticulturists and other persons interested are
urged to report promptly to the Department of Agriculture any
outbreak or suspicious symptoms of the above-described disease.

PLATE I. — THE UNDER SURFACE OF RUST-INFESTED CURRENT LEAVES.
A. UBEDO AND TETEUTO SORT OF CRONARTIUM RIBICOLA ( X 4 ) .

B. TlIE SAME, MORE ENLARGED.

PLATE II. — THE CURRANT AND PINE RUST.

Cronartium ribicola.

1, Uredo and teleutospore stages on leaf of black currant; 2, Uredo-
spores, a, and telutospores, I), cemented together to form an erect,
hairlike structure (X50); 3, Uredospore, (X300) ; 4, Four teluto-
spores, two of which are germinating, and one of the germ-tubes has
produced four sporidia or secondary spores (X300) ; 5, Aecidia on bark
of white pine; 6, Aecidiospores (X300). (After Massee.)

APPENDIX

AN OUTBREAK OF THE EUROPEAN CURRANT RUST

(Cronartium Ribicola Dietr.)

Reprinted from Technical Bulletin No. 2 of the New York
Agricultural Experiment Station at Geneva; W. H. Jordan,
Director.

By F. C. Stewart,

CIRCUMSTANCES ATTENDING THE DISCOVERY.

While passing the currant plantation on the Station grounds
September 20, 1906, the writer observed an unusual appearance
of the foliage on some plants. Upon plucking one of the leaves
for examination we were astonished to find the under surface
yellow with a rust. Even to the unaided eye it was -evident that
the rust belonged to the genus Cronartium and upon miscroscopic
examination in the laboratory it proved to be Cronartium ribicola
Dietr., a currant fungus of common occurrence throughout Europe
but hitherto unknown in America.

The plantation in which the rust was found is one devoted to
the testing of varieties. It contains about 175 plants and includes
54 different varieties representing three species; viz., Ribex
nigrum, R. rubrum, R. aureum. Most of the plants were set in
the spring of 1903, being transplanted from another plantation
about forty rods away. The remainder of the plants were set
in the spring of 1904. They varied in height from two to five feet.

Of the 54 varieties, 48 were more or less rusted while the other
six were free from rust. The several varieties of black currants,
Ribes nigrum, were most affected — Monarch, Clipper and Star
being among the worst and having almost every leaf thickly cov-
ered with rust. In spite of this severe attack of rust the black
currants were in full foliage. Some of the red and white varieties,
R. rubrum, also were severely attacked, but most of them were
only slightly affected. The plants of this species had already
lost a considerable portion of their foliage from leaf spot, Septoria

9

rib is. One variety of E. aurcinn (Jelly) showed traces of rust.
Four varieties of E. rubrum (Prince Albert, Gondouin White,
Stultz and an unknown variety) and two varieties of E. aureum
(Crandall and Utah Golden) were entirely free from rust.

The infested currant plantation was adjoined on the west by a
plantation of goseberries .containing many different varieties.
Only one variety (Pearl) was affected and this but slightly.

In another part of the Station grounds, near the Director's
residence and about forty rods east of the infested plantation,
there are planted sixteen different species of Eibes, including E.
aureum, but neither E. nigrum nor E. rubrum. Of these only
one species, E. irriguum, was affected. There were two plants of
E. irriguum and both were severely attacked.

DESCRIPTION OF THE FUNGUS.

The fungus Cronartium ribicola was first described and named
by Dietrich fifty years ago. It appears during the summer and
autumn as a conspicuous orange-colored powder on the under sur-
face of the leaves of various species of Ribes (currants and goose-
berries). Two forms of spores, uredo- and teleutospores, are pro-
duced on Ribes leaves. The uredospores are ellipsodial to ovoid,
19-35 x 14-22 M with orange-colored contents and borne in sori
forming pustules. The teleutospores are elongated, unicellular
and massed together into peculiar orange-colored columnar pro-
cesses which attain a maximum length of about two millimeters.
These processes are usually curved. To the unaided eye they ap-
pear like coarse, yellow plant hairs, hence the German name
"Filzrost" (felt-rust).

Another form (the aecidium form) of the currant rust fungus
occurs on the trunks and branches of Finns spp., especially the
white pine, Pinus strobus, producing a disease called blister rust
(Blasenrost of the Germans). The pine-inhabiting form was first
described by Klebahn in 1887 as a distinct species and by him
named Peridermium strobi. Subsequently, through inoculation
experiments made by Klebahn and others, it was conclusively
proven that Cronartium ribicola on the currant and Peridermium
strobi on the pine are not separate species but only different stages
of one and the same fungus.

10

GEOGRAPHICAL DISTRIBUTION AND ECONOMIC

IMPORTANCE.

Crona/rtium ribicola occurs in. several European countries, and
probably in India, but has never been found in Australia or in
South America and in North America but once.

It was originally described in 1856 from specimens collected
in western Russia. Since that time it has been reported from
other places in Russia even to the Ural Mts. on the east and
to the Caucasus Mts. on the south. In Germany it is common
and the injury which it does to the white pine is of considerable
economic importance. Klebahn has reported a destructive out-
break of the disease among white pines in the vicinity of Bremen
in 1887. Tubeuf, in 1898, stated that specimens of it were to be
found all over Germany and that it was destructive in the north-
eastern part. Among other instances of severe damage he men-
tions a large nursery near the Holland border in which the culture
of white pines had been entirely given up on account of the fungus.
In another publication the same author stated that the disease was
spreading and becoming a serious menace in Germany. Eriksson
describes its epidemic occurrence in Sweden. Bos states that in
Holland it is so abundant that in many localities the culture of
white pines is impossible. It is also reported from Belgium,
Denmark, Norway, Switzerland, France, Austria and England.

Judging from the European literature on the subject, it ap-
pears that as a currant disease Cronartium ribicola is regarded as
of little importance even in those regions in which it is abundant,
but as disease of white pines it has caused much damage.

American mycologists, believing that it must eventually make
its appearance in this country, have been on the lookout for it
for many years; but with the exception of the Bartholomew col-
lection previously mentioned it has not been found anywhere in
the Americas. No Cronartium on any species of Ribes and no
Peridermium on Pinus strobus are known to America. The fact
that America is the home of the white pine makes the absence of
Cronartium ribicola especially noteworthy. Magnus, Klebahn,
and others have commented upon this and discussed the probable
origin of the fungus. The most plausible theory advanced regard-

11

ing the origin of Crorwrtium rlbicola is that its original host was
the Swiss stone pine, Pinus cembra, and that it was introduced
into Germany in recent times from Russia where Pinus cembra
forms extensive forests. Schellenberg expressed the opinion that
it is also indigenous in the Swiss Alps on Pinus cembra.

It is altogether probable that the apparent absence of Cronar-
tium ribicola from America is real; or at least the fungus cannot
have existed here long. It is unlikely that collectors have over-
looked it. Both on the currant and on the pine it is conspicuous
and readily identified. The horn-like masses of teleutospores are
characteristic and serve to distinguish it from other rusts occur-
ring on Ribes leaves.

ORIGIN OF THE GENEVA OUTBREAK.

It would be interesting to know the origin of the outbreak
at Geneva, but from the data now in hand it is not possible
to locate definitely the original source of infection. It is likely
that the fungus was imported with pines rather than with cur-
rants or gooseberries, since it is perennial within the steins and
branches of the pine, while on Ribes it is confined entirely to the
leaves. The only white pines in the immediate vicinity of the
diseased currant plantation are two small trees standing 125
feet to the west. These were purchased from a Geneva nursery
and set eight years ago. From a careful examination of these
trees made in November they appeared in thrifty condition with-
out any indication of Peridermium. Nevertheless, they may be
the source of infection, notwithstanding their seeming freedom
from disease. Peridermium strobi should be sought in April and
May ; by November it is difficult to recognize.

The two trees just mentioned are the only white pines on the
Station grounds ; and there are no specimens of Pinus cembra, P,
lambertiana, P. monticola or any other Pinus having leaves in
clusters of five. The nearest other possible sources of infection
are a 12-feet-high Pinus strobus sixty rods east, an aged Pinus
strobus about eighty rods north and a sixteen-year-old Pinus cem-
bra the same distance to the southeast. There are several nur-
series in the vicinity of Geneva and it may be that some one of
them has imported diseased pine trees. The nearest nursery con-
taining pines liable to the disease is about one-half mile west
of the Experiment Station. It contains a block of Pinus cembra

12

and some Pinus strobus imported from France. Here may be the
source of infection. However, contradictory evidence is found
in the fact that a plantation of red currants (Ribes rubrum) di-
rectly across the road from this nursery was practically free from
Cronartium. A careful search revealed just one leaf affected with
Cronartiwm ribicola, which was in the teleuto stage. Another
plantation of red currants between the nursery and the Experi-
ment Station was entirely free from Cronartium. In fact the
single affected leaf above mentioned is the only instance in which
the Cronartium has been found outside the Station grounds al-
though the neighboring currant plantations were carefully
searched. Thus, the indications are that the source of infection
is on the Station grounds.

This raises the question whether it is possible that the out-
break may have resulted from uredo- or teleutospores brought
onto the Station grounds with imported currant plants. During
the past ten years the Station has made several importations of
currant and goseberry plants, the latest one being from Hex-
ham, England, in the spring of 190-4. Can these plants have been
the source of infection ? It has already been stated that the
aecidium stage of Cronartium ribicola occurs on certain species
of Pinus, especially P. strobus. It has been proven that the uredo
stage on the currant may start from infection with aecidiospores
from the pine; and that the aecidium stage on the pine may result
from infection with teleutospores from the currant. Further, it
is believed, but not conclusively proven, that aecidiospores can not
infect pines and teleutospores can not infect currants. The uredo-
spores may infect currants directly, but they do not survive the
winter. In short, in the absence of pines the currant rust can not
perpetuate itself. This is the generally accepted view and if it is
a correct one the Geneva outbreak of currant rust could not have
come directly from imported currants. However, some eminent
mycologists have expressed doubt 011 this point. Eriksson, Fischer,
Iwanoff, Nilsson, and Speschneff have all cited cases of the occur-
rences of Cronartium ribicola on currants in localities where
Pinus Strobus was lacking; and Eriksson, particularly, has ex-
pressed the opinion that it may live from year to year on currants
entirely independent of the aecidium stage on the pine. Klebahn,
on the contrary, believes that this view should not be accepted
without thorough investigation. In none of his numerous inocula-

13

lion experiments was there a recurrence of 'Cronartium the fol-
lowing season. In our own case the outbreak on currants can not
be satisfactorily accounted for except on the assumption that the
two nearby Pinus strobus trees were diseased last spring. It may
be possible to determine this point next spring. If it can be proven
that these trees were free from Peridermium in the spring of 1906
then it would seem that we have here evidence in support of
Eriksson's view; for it is scarcely possible that pine trees sixty
rods or more distant can have been responsible for so abundant
an infestation.

ATTEMPT AT ERADICATION.

In order to stamp out the disease, if possible, every Ribes plant
on the Station grounds has been destroyed. The two white pines
standing by the currant plantation, also, will be destroyed if they
show the disease next spring.* A careful wratch will be kept over
pines and currants in the vicinity of the Station and in case of
the appearance of the disease next season measures will be taken
to secure the prompt destruction of all affected plants. Perhaps
the disease may be stampted out, but the chances are against it.
The writer knows of no record of a successful attempt at the com-
plete eradication of a fungus disease of plants. It is rarely at-
tempted.

Even should this attempt prove successful, it can -not be ex-
pected that the disease can much longer be kept out of America.
Considering the frequency with which pine trees are imported it
is a wonder that the disease has not made its appearance here be-
fore.

ITS PROBABLE IMPORTANCE IN AMERICA.

It is improbable that growers of currants and gooseberries in
America have much to fear from this new disease. Even when
currant leaves are abundantly infested with the rust fungus they
appear to be but little injured by it. On the Station grounds
black currants which were badly infested held their leaves until
well into October.

The chief danger from Cronartium rilncola lies in its effect on
pine trees, particularly the white pine. In parts of Europe it
has wrought havoc among white pines and there is no apparent

* These trees have not shown presence of Prridermium Strobi though ex-
amined carefully since 1006.

14

reason why it should be less destructive in America should it he-
come established here. Indeed, it may become even more de-
structive. It has not infrequently happened that a parasitic fun-
gus introduced into a new country has become more virulent in
its attack and caused greater damage than in its native country.
There is also the possibility that it may extend its list of host
plants. In Europe it is known to attack only four species of
Pinus; viz., P. strobus, P. cembra, P. lambertiana and P. monil-
cola, all of which bear their leaves in clusters of five.

TREATMENT.

Since it is probable that pine trees and Kibes plants are both
necessary to the perpetuation of the Cronartium, the destruction
of all specimens of either of these two kinds of host must result in
the extermination of the rust. Accordingly, the principal
method of control recommended by European writers is the de-
struction of which ever of the two hosts is the least valuable.
Wherever there is danger of the disease, currants or gooseberries
should not be planted near white pines.

It is possible that on currants and gooseberries the rust might
be controlled by spraying with bordeaux mixture, but no experi-
ments have been made. On the Station grounds one application
of bordeaux mixture made as soon as the fruit had set apparently
had no effect on the rust.

BIBLIOGRAPHY OE CRONARTIUM RIBIOOLA AND
PERIDERMIUM STROBI.

With the appearance of Cronartium ribicola in this country
there is likely to come renewed interest in it. In order to facil-
itate the labors of American mycologists who wish to examine
the literature of the subject, the following *biblography has been
compiled. It is not quite complete and several of the articles
have not been seen by the writer. By far the most important of
the references given in Klebahn's book, Die wirtwechselnden
Rostpilze, which contains an authoritative resume of the whole
subject with numerous citations of literature.

* For Bibliography see Technical Bulletin No. 2 referred to.

15

Bulletin 94. May, 1895.

Cornell University Agricultural Experiment Station,
BOTANICAL DIVISION.

DAMPING OFF

By QEO. F. ATKINSON.

PUBLISHED BY THE UNIVERSITY,

ITHACA, N. Y.

1895.

ORGANIZATION.

BOARD OF CONTROL:

THE TRUSTEES OF THE UNIVERSITY.

STATION COUNCIL.

President, JACOB GOUI^D SCHURMAN.

Hon. A. D. WHITE, - Trustee of the University.

Professor I. P. ROBERTS, President State Agricultural Society.

Professor I. P. ROBERTS, - Agriculture.

Professor G. C. CAI,DWEUO - Chemistry.

Professor JAMES LAW, - - Veterinary Science.

Professor A. N. PRENTISS, Botany.

Professor J. H. COMSTOCK, - - Entomology.

Professor L. H. BAILEY, - Horticulture.

Professor H. H. WING, - Dairy Husbandry.

Professor G. F. ATKINSON, Cryptogamic Botany

OFFICERS OF THE STATION.

I. P. ROBERTS, Director.

E. L. WIUJAMS, - - Treasurer.

H. W. SMITH, - Clerk.

ASSISTANTS.

M. V. SLINGERLAND, Entomology.

GEO. C. WATSON, - Agriculture.

G. W. CAVANAUGH, Chemistry.

E. G. LODEMAN, Horticulture.

MICHAEL BARKER, .... Horticulture.

Office of the Director, 20 Morrill Hall.

Those desiring this Bulletin sent to friends will please send us the names
of the parties.

BULLETINS OF 1895.

84. The Recent Apple Failures in western New York.

85. Whey Butter.

86. Spraying of Orchards.

87. The Dwarf Lima Beans.

88. Early Lamb Raising.

89. Feeding Pigs.

90. The China Asters.

91. Recent Chrysanthemums.

92. Feeding Fat to Cows.

93. The Cigar Case-Bearer.

94. Damping Off.

The potting bed fungus, Artotrogus debaryanus (Hesse}.

Damping of prothallia, Artotrogus intermedius (deBary}.

Note on the genus Artotrogus.

A potting bed fungus new to America, Completoria complens Lohde.

A new cutting bed fungus, Volutella leucotricha Atkinson.

Canker in cucumbers.

Damping off by a sterile fungus.

DAMPING OFF.

' ' Damping off " is a disease of seedling plants which rots or
disintegrates the tissues at the surface of the ground. The tissues
thus changed weaken, lose their firmness and supporting power,
and the seedling falls prostrate on the soil. The disease is wide
spread and sometimes very common. It occurs not only in gar-
dens and fields but is a very frequent attendant upon the culture
of seedling plants in the forcing house or bed. The trouble is
favored by damp soil, comparatively high temperatures, and
humid atmosphere.

The term "damping off" is therefore indicative of one of the
attendant conditions of the soil inducing the disease. While this
popular expression is thus far significant of the trouble it is by no
means the exact statement of the case. The plants do not damp
off because of the abundant damp or moisture in the soil. The
dampness encourages the growth of minute parasitic plants, not
visible to the unaided eye, which pierce the seedling, feed upon
its substance and set up disintegration processes which result in
the death and collapse of the affected parts. Soon after the plant
falls the dissolution of the tissues near the surface of the ground
has usually proceeded so far that communication by the ordinary
physiological processes of life is cut off, and the plant then with-
ers and dies. While damping off is due to the action of minute
fungus parasites, it is by no means caused by one and the same

Frontispiece. This is from a photograph of an experiment to show the
parasitic nature of the Artotrogus debaryanus (Hesse). Before planting the
cucumber seed the pots were* filled with soil which was thoroughly wetted
and then steamed in the steam sterilizer for several hours on three successive
days in order to kill all the organisms. The seed was then planted and when
just coming up some plant tissue with freshly developed stages of the fungus
was placed by the seedlings in pots 5, 6, and 8, while pot 7 was left as a
check. The result can be easily seen in the photograph, the check plants
remaining unharmed while all the plants in 6 are killed and only one re-
mains healthy in each of 5 and 8.

234 BULLETIN 94.

species. Different species of fungi may under some conditions
produce nearly or quite identical phenomena in the progress and
culmination of the disease. Some species develop phenomena
allied to genuine cases of damping off, and the final result of
which is practically the same, the decay of the stem near the sur-
face of the ground and the collapse of the seedling.

Some variations in the external appearance furnish diagnostic
characters correlated with the presence of certain species of the
parasite, but it is doubtful if in any case the specific cause should
be confidently asserted without recourse to microscopic examina-
tion, sometimes to be preceded by special treatment. In dis-
cussing the several species of fungi which have been found to con-
tribute a share in the production of the disease it will be conven-
ient to take up first the species to which the trouble is generally-
attributed, and then to follow with others which play a more or
less important part in the development of similar or nearly identi-
cal troubles.

THE POTTING BED FUNGUS.
Artotrogus debaryanus1 (Hesse).

This fungus is responsible for a large part of the damping off
of young seedlings. It is very widely distributed, being very com-
mon in the soil of gardens and also in the forcing house. It is
common also in many fields, but it probably is more abundant in
soil where numbers of plants are grown from the seed in a more
or less crowded condition, especially those plants which are known
to be predisposed to its attacks. It has however been found in
virgin soil taken freshly from the woods into the forcing house.2

It is thus a very common and unwelcome bed-fellow and pot-
companion of many seedling plants which are more or less crowded

1 Pythium debaryanurn Hesse. The name Pythium was used in 1823 as a
generic name for two species (Mucor spinosus Schrank, and M. impercepti-
bilis Schrank, Denkschr. d. k. acad. d. wiss. z. Munschen, 1813, 14) by Nees
von Esenbeck Nova acta acad. Leop. XI, 2,515, which belong to another
genus (Achlya, see Fischer, Rabenhorst's Krypt. Flora. IV, 332). Artotrogus
(Montagne, Sylloge, 304, 1845) was the next name which was used for a
member of this group and must consequently take the place of Pythium
Pringsheim, Jahrb. wiss. Bot. II, 303, 1860.

2Humphrey, 8th Ann. Rept. Mass. St. Agr. Bxp. Station, 221, 1860.

DAMPING OFF. 235

in the seed bed or forcing pots of our gardens and hot houses,
especially if undue moisture is present in the soil. In the gardens
it is frequently impossible to control the amount of moisture in the
soil, and in the forcing house where often the light is defective,
the air is not fresh or it is supercharged with moisture, it is often
nearly or quite impossible by the ordinary methods to preserve
that equilibrium of environment which will permit the growth of
the seedling and at the same time check the growth of its inimical
guest.

All experienced gardeners are probably familiar with the appear-
ance of the diseased seedling when affected with the damping off
fungus. At this day when the germ theory of disease, both animal
and plant, has so completely poisoned the minds of all classes of
people there is little difficulty in successfully advocating what is
now an established fact, that the damping off fungus is a parasite
in the seedlings and invades the tissue of the latter for the pur-
pose of obtaining its food. It is fortunate therefore that especial
attention can be given to setting forth the facts in the structure
and development, and other peculiarities of the parasite, which
are quite important to know in order to properly treat it, and also
because it can then be distinguished from others either near or
remotely related, some of which induce diseases in the early
life of certain ferns or fern-like plants and cannot disease
seedlings.

The first striking pecularity in a bed or pot of seedlings affected
with the disease which attracts our attention is the prostrate con-
dition of a few plants while others are upright and apparently
healthy. The prostrate plants are found to be shrunken at or
near the crown, i. e. near the root or the surface of the ground.
Frequently when our attention is thus first called to the disease
the collapsed tissue of some of the prostrate plants is so far dis-
integrated as to be in a soft and rotted condition, so that on pull-
ing at the plant it breaks easily at this point. Farther investiga-
tion will show that usually the entire root system is by this time
decayed, while the greater part of the stem above ground and the
young leaves are still green and possibly quite fresh, or flabby, or
more or less wilted.

236 BULLETIN 94.

The conditions of the aerial portions of the plant at this early
stage of its fall are largely dependent upon the moisture content
of the atmosphere. If the moisture be quite dry the seedling will
be quite flabby before it falls and will soon wilt thereafter, but if
the moisture content is large the tissue will remain quite firm for
a time unless the soil upon which it is lying is so saturated with
moisture as to encourage the rapid growth of the fungus in the
prostrate portion of the plant. When this is the case the entire
plant soon becomes a putrid mass and the tissues often take on a
dark color.

After attention has been called to the trouble by the preliminary
collapse of a few plants, if others are carefully noted some will
probably present a paler green color than the perfectly healthy
ones, especially near the surface of the ground. If such plants
are carefully examined they will probably show the presence of
the fungus in the tissues of the root and lower part of the stem,
for the fungus requires several hours after entering the tissues to
produce such changes which would be visible to the unaided eye.

Mycelium. If from one of these prostrate plants a portion of
the collapsed part of the stem is teased apart on a glass slip, such
as is used in microscopic work, in a little water and then examined
under the microscope the vegetative phase of the parasite will prob-
ably be apparent. It exists as slender, colorless, thread-like
irregular tubes, which appear to be more or less tangled in the
tissues of the seedling. These tubes are the hyphae, as they are
called, of the fungus, and collectively make up the mycelium.
The hyphae are branched in quite a profuse manner, the succes-
sive branches usually forming somewhat more slender hyphae than
the parent ones, so that the main hypha is frequently larger than
the branches.

The hyphae course between and through the cells. Where a
hypha passes through a cell wall it is very much constricted or
very much more slender than it is in the cell lumen of the seed-
ling or between the cells. The hypha in boring its way through
these walls excretes a ferment, it is supposed, which dissolves the
cellulose of the walls at the point of contact. A quite minute
opening in the wall is sufficient for the growing end of the hypha
to squeeze its way through and maintain communication with the

DAMPING OFF. 237

older portion, and has the advantage of requiring a much less ex-
penditure of energy than if the opening were made of the same
size as the hypha. After passing through the cell wall the hypha
enlarges to the normal size.

While the mycelium is comparatively young the inner portion
of the hypha is continuous, i. e., there are no cross walls parti-
tioning the tubes into sections. This is a characteristic possessed
by a very large group of fungi to which the Artotrogus belongs,
known as the Phycomycetes. The protoplasm within the hypha is
finely granular when the mycelium is young, but in the larger
threads as they become older the granules become coarser, their
contents are not so homogeneous, and the granules tend to collect
into groups or very irregular masses, somewhat resembling the
protoplasm in some mucors.

In a crowded seed bed after a few plants have fallen, unless the
disease is checked, it will spread from these affected ones as cen-
ters to others near them and thus from the one or several starting
points the plants will fall until nearly or quite all of them have
been killed. Where the soil and atmosphere is quite damp and
the temperature conditions so high as to favor rapid growth of
the fungus it will grow out from the diseased part of the stem into
or on the surface of the soil for a few millimeters in extent as a
very delicate cottony mass or velvety pile. Where the adjacent
plants are not too far distant the superficial threads may thus
reach them and communicate the disease to them. In other cases
minute motile reproductive bodies called zoospores, or swarm spores
(perhaps more properly zoogonidid] are developed in a manner to
be described later. These swim in the soil water to the more dis-
tant seedlings and thus spread the disease.

Sometimes there will be seen quite a profuse growth of a my-
celium, which on the surface of the soil may spread several cen-
timeters in extent. Usually this profuse growth is that of another
fungus, a Rhizopus, or Mucor, or in other cases a different ' ' damp-
ing off" fungus to be described in a later paragraph.

If the tissues examined as described above from a seedling
which has not remained long after falling over perhaps the con-
dition of the mycelium described will be the only phase of the
plant (for the fungus is a plant) at that time present. If it has

238 BULLETIN 94.

been dead for sometime, however, there will probably be seen
here and there on the hyphae a number of rounded or spherical
bodies, three to five times the diameter of threads of the mycelium
with which they are connected. These are reproductive organs of
the fungus and will soon be described.

The characters of the mycelium alone are not in all cases suffi-
cient for the correct determination of the plant. L,et then this
preparation on the glass slip lie free in an abundance of water, and
place the slip in a small moist chamber sufficiently protected so
that the air in the chamber will not become dry by evaporation at
the point of contact of the two vessels. This can be avoided by
placing a sheet of wet filter paper between the cover and the edges
of the bottom vessel. A Petrie dish, such as is used in bacterio-
logical work, is excellent for the purpose. Some wet filter paper
should also be placed in the bottom and on this the support for
the glass slip can be placed. For hasty examination the material
can be teased out directly in the bottom vessel of the Petrie dish
in a little water, and then this can be placed on the stage of the
microscope whenever it is desired to examine it.

In twelve to twenty-four hours if the preparation is again exam-
ined many threads of the fungus will be seen to have grown out
from the tissue and spread on all sides for a distance of one to
two millimeters in the surrounding water, now presenting the
characters noted above in a clear manner, except there are no con-
strictions of the hyphae corresponding to those where they pass
through the cell walls of the host. The branching is in an alter-
nate or irregularly monopodial fashion. There will also be seen
numbers of the rounded bodies noted above on the mycelium, both
within the tissue and on the mycelium which is growing free in
the water around its margin.

Sexual organs. Oogonia. The larger number of these rounded
bodies in the case of this species will probably be what are termed
oogonia. These are developed in several relations to the hyphae
which bear them. They may be terminal, i. e. on the ends of the
hyphae which bear them, or on the ends of quite short branches,
or intercalary, i. e. when they appear as swellings of the hyphae
here and there without any reference to the end.

A terminal oogonium begins as a slight swelling of the rounded

DAMPING OFF. 239

end of a hypha or short branch, which continues until the spheri-
cal body is about 1 8/^-2 5/Jt in diameter. During its growth in size
the protoplasm which fills the interior is supplied by the support-
ing hypha or oogoniophore, without, however, emptying any
portion of the latter structure. When the oogonium has reached
its full size, a septum, or partition wall, is formed cutting off its
protoplasm from that of the stalk or oogoniophore. At this time
the wall of the oogonium is thin and the protoplasm finely granu-
lar, though distinctly so, and completely fills the interior of the
oogonium. The wall now increases somewhat in thickness, but
remains colorless.

The egg cell of the oogonium is now soon differentiated, and
in most cases, except where parthenogenisis takes place, is prob-
ably influenced by the development of the antheridium. The
finely granular protoplasm of the oogonium becomes coarser and
is gradually collected into numerous small irregularly rounded
masses. At the same time all of the coarsely granular protoplasm
contracts from the wall of the oogonium and moves toward the
center forming there a rounded central mass somewhat less in
diameter than that of the oogonium, being 14^— 18// in diameter.
This central sphere of coarsely granular protoplasm is termed the
oosphere, or egg cell, and is really an unfertilized egg, the recep-
tive cell of the oogonium. Between this egg cell and the wall of
the oogonium is a space filled with a nearly clear, but finely
granular and homogeneous fluid called the periplasm. At this
stage there is no wall surrounding the egg cell and it is ready to
be fertilized.

Antheridia. — The sole purpose of the antheridia is to supply
the fertilizing element for the egg cell, and the antheridium is
sometimes termed the supplying gamete, while the oogonium is
termed the receptive gamete. The antheridia are of two kinds,
stalk antheridia and branch antheridia. A stalk antheridium is
formed from a section of the oogoniophore by the formation of a
partition wall in the hypha cutting off an elongated cell one end
of which is thus in contact with the wall of the oogonium, and
its contents are only separated from those of the oogonium by the
wall of the latter. This is the simplest of the two forms of the
antheridia.

240 BULLETIN 94.

A branch antheriditim is developed as a lateral branch of the
oogoniophore, arising usually quite near the oogonium, but some-
times more or less remote from it, rarely on a separate hypha.
The branch grows towards the oogonium and its rounded end
comes in contact with the oogonium wall and becomes fixed at the
point of contact. A septum is now formed in the branch cutting
off an elongated cell varying from 15/4-40;'.. This cell, one
end of which is in contact with the oogonium wall, is the anthe-
ridium, and the proximal portion of the branch is the antheridio-
phore. More than one antheridium may be formed in connection
with a single oogonium, frequently two and sometimes three.
Both may be branch antheridia, or one may be a branch antherid-
ium and the other a stalk antheridium, and other combinations
may take place where more than two antheridia are present.
There does not seem to be any rule in the number of antheridia
which take part in the fertilization of the egg cell. Where several
are in contact one or more may take part in the act of fertilization.

When the antheridial cell is formed its farther development is
the same whether it be a branch antheridium or a stalk antherid-
ium. The cell which is cylindrical or nearly so in form begins to
swell and this continues until it is two to three times the original
diameter, the greatest diameter being near the end which is in
contact with the wall of the oogonium. At the same time it also
becomes quite strongly curved and more or less twisted. In case
the oogonium is a terminal one and possesses both a stalk anther-
idium, and branch antheridium, the stalk antheridium may curve
so strongly to one side as to make it difficult to determine later
which is really the stalk antheridium.

While these changes are taking place in the antheridium the
granular protoplasm of the oogonium is moving toward the center
to form the egg cell as described above, and now the end of the
antheridium in contact with the wall of the oogonium, puts out a
slender tube which pierces the oogonium wall, extends across the
space occupied by the peri plasm and touches the egg cell at the
nearest point. This tube is known as the fertilization tube. At
this point on the egg cell there is a small clear space called the
receptive spot.

Nearly all of the protoplasm in the antheridium except a very

DAMPING OFF. 241

thin layer next the wall becomes coarsely granular, arranged in
strings and is finally collected in the middle line of the antherid-
ium. This is known as the gonoplasm, and soon passes through
the fertilization tube and is emptied into the egg cell at the recep-
tive spot, where it disappears in the substance of the egg cell and
completes the act of fertilization.

While the passage of the gonoplasm is going on it can be seen
that a thin wall is forming around the egg cell over the surface
except at the point where the fertilization tube is located. When
the gonoplasm has passed through, the wall becoms complete at
that point, and the entire wall then thickens somewhat and soon
becomes brown in color. The fertilized egg cell now becomes the
egg, or oospore.

These phenomena in the development of the oogonia and an-
theridia and in the fertilization of the egg cell can be quite easily
followed by teasing out a small section of the diseased plant tissue
in water on a cover glass and arranging this for a cell culture in
what is known as a van Tiegham cell. This^can be placed on the
stage of the microscope from time to time and the development
traced. From such a culture made from a diseased young melon
seedling the following record was made. The diseased tissue was
teased out in water on a glass slip Monday, Jan. 28, and placed
in a moist chamber. The following day, Jan. 29, a profuse
growth of mycelium, oogonia and antheridia had taken place, the
mycelium extending for 2mm to 3mm out from the diseased tissue.
Jan. 30 a small portion of this tissue was farther teased out and
mounted in fresh water in a cell culture. Jan. 31 farther growth
had appeared and new oogonia and antheridia were developed.
This continued for several days in the same culture.

On Feb. i at 12:30 p. M. as shown in fig. i, the egg cell in the
oogonium has formed and the antheridium curved over on one side
is full size but the fertilization tube has not yet formed nor has the
gonoplasm differentiated, the granular protoplasm being arranged
in a network of threads. At 3:15 P. M. of the same day as shown
in fig. 2 the fertilization tube is complete, the gonoplasm has
formed and is about to pass through the tube, while a very thin
wall is forming around the egg cell except -at the receptive spot.
At 9 P. M., fig. 3, the gonoplasm has passed through and the wall

242 BULLETIN 94.

of the oospore is complete. Fig. 4 represents an intercalary
oogonium which was observed in the stage figured, at 12:30 p. M.,
Feb. i. Two antheridia are here in contact with the oogonium
s. a. a stalk antheridium and b. a. a branch antheridium. In both
cases the fertilization tube is complete, and the gonoplasm has
separated preparatory to passing through. The curving of the
stalk antheridium has turned the main thread to one side, the
branch antheridium arising quite closely by the side of the
oogonium has curved inward to the wall of this organ. At 3:30
p. M., fig. 5, the gonoplasm has passed through the fertilization
tube from both antheridia and a thin wall has formed around
the now fertilized egg. Fig. 6 at 12 p. M., showed a terminal
oogonium with two antheridia, one a stalk antheridium and one a
branch antheridium, it being difficult in this case to say which is
the stalk and which is the branch. An accident happened to this
specimen and it was not seen again. Fig. 7 represents two ter-
minal oogonia each with a stalk antheridium, first observed at 9
p. M., Feb. i. At this time in the case of oogonium a, the egg
cell is formed, and the gonoplasm in the antheridium has sepa-
rated, while in oogonium b, the egg cell has not yet formed. From
the fact that the stalk antheridium was on the under side of
oogonium d, when it was first observed, the stage of its develop-
ment could not be seen. At 2 p. M., on Feb. 2, however, fertili-
zation was completed in both as shown in fig. 8. Fig. 9 repre-
sents an oogonium with a fertilized egg and two antheridia in con-
tact with its wall ; one, a, a stalk antheridium whose gonoplasm
took part in the act of fertilization, and one, b, a branch antheri-
dium from a different hypha from that on which the oogonium is
borne. From the latter the gonoplasm was not used.

These oospores or fertilized eggs mark a very important phase
in the life history of the fungus. They will eventually germinate
and produce the mycelium again, which under favorable condi-
tions will start the disease anew. But the remarkable thing about
the oospores is that they cannot germinate immediately, except in
rare instances, but must undergo a long period of rest, and hence
are sometimes termed resting spores. In this condition they are
capable of resisting degrees of cold and dryness which would prove
fatal to the vegetative portion of the fungus. This accounts partly

DAMPING OFF. 243

for the appearance of the disease after long periods of drought and
after the inclement weather of the winter season in some sections.

Not only does the thicker wall of the oospore offer greater pro-
tection against an unfavorable environment, but the protoplasm
undergoes a marked change before it finally enters upon this en-
forced period of rest. This change is practically a metamorphosis,
the complete nature of which we do not understand. Among
other changes there is probably a change in the molecular or
physical structure of the protoplasm by which a large amount of
a fatty substance is separated and forms a very large globule and
sometimes other smaller ones which occupy a large part of the
space of the oospore. The protoplasm thus becomes transformed
into a state highly resistant to outside conditions and incapable of
growth for a long period, even though the environment may be
most favorable for growth. The period of rest lasts for several,
four to five, months. They will resist freezing for weeks, fol-
lowed by drying, without injury.

Propagative organs. Organs of another kind than oogonia and
antheridia are developed on the mycelium. The function of these
is chiefly for the immediate and rapid propagation of the numbers
of the parasite. The organs are, like the oogonia, either terminal
or intercalary swellings of the hyphae, and at first do not differ
materially from them before the defferentiation of the egg cell
and antheridium. These organs are exactly alike in form but
differ in the discharge of their functions and are termed respec-
tively, conidia, resting conidia, and zoosporangia.

Conidia. The conidia measure about the same as the oogonia
and when fresh water is added to them they will germinate im-
mediately after maturity, which is attained upon reaching their
full size.

Resting conidia. These are conidia which do not germinate
immediately and acquire a somewhat thicker wall than the con-
idia. They pass through a period of rest before germinating.
They are identical in form and size with the conidia. They are
capable of growing after being frozen, and after drying, and serve
in this way much the same function that the cospores do in that
they tide the fungus over quite long periods which are unfavor-
able for the growth of the plant.

In germination the conidium thrusts out, by an extension of

244 BULLETIN 94.

its wall, at one or more points, a slender tube which elongates
into a hypha exactly like those of the former mycelium. This
enters a young seedling when favorably situated, and stajts the
disease again.

The conidia and zoospores are rarely developed so abundantly
in this species as are the oogonia. In my cultures during Jan.
and Feb. 1894-5 the oogonia were far more abundant and no zoo-
sporangia were observed. DeBary says that sometimes one may
search for weeks and even months and not find zoosporangia. I
have therefore not had as yet an opportunity of studying the for-
mation of the zoospores from the zoosporangia and cannot say
whether or not they agree with those of Artotrogus intermedius
(deBary), which will be described in the next paragraph. The
following account is therefore abbreviated from published descrip-
tions.3 The zoosporangia are usually not to be differentiated from
the conidia until the time for the development of the zoospores.
They are either terminal or intercalary, and sometimes so much
of the protoplasm migrates into them during development from
the supporting hypha that this is emptied for a short distance
near the point where the wall separates the zoosporangium from
the contents of the hypha. They usually remain attached to the
supporting hypha and at the time of maturity, if placed in fresh
water containing oxygen, a short protuberance is developed on
one side at nearly right angles to the supporting hypha, which
grows to a very short tube of a varying length but always shorter
than the diameter of the zoosporangium. Into this tube the pro-
toplasm migrates and causes the end of the short tube to swell
out into a rounded vesicle of about the same diameter as that of
the zoosporangium, with a thin enclosing membrane. The pro-
toplasm now breaks up into a number of kidney shaped masses,
with two lateral cilia according to most authors, although Hesse4
who first described the process in this species says that the zoo-
spores are oval and uniciliate. These swarm about in the water
for a few minutes, come to rest, round off and germinate in the
ordinary way for conidia by sending out a slender germ tube

3 DeBary, Zur Kennt. d. Peronosporeen, Bot. Zeit. 39, 521, 1881, Beitr. z.
Morph. u. Phys. d. Pilze, IV, 1881.

Schroeter, Pilze, in Engler u. Prantl, Naturl. Pflanzenfam. i, i 104.

4 H23se, Pythiutn deb.aryanutn, ein entophytischerschmarotzer, Halle, 1874.

DAMPING OFF. 245

which when favorably situated will start the disease in fresh
plants. It is probably by the development of these in wet soil
during rain or at the time of watering the pots or soil in seed
beds that the disease is spread so rapidly.

The fungus is however capable of developing as a saprophyte
on dead or partially decayed organic matter in the soil so that
with one watering it may become well seated in nearly all parts
of the bed. To show that it is also a saprophyte it is a very easy
matter to start it in the laboratory on the leaves or stems of seed-
lings which have been previously killed by boiling.

This damping off fungus was first described by Hesse in 1874
(1. c.) and named by him Pythium debaryanum. It was shown
by him to be a parasite of seedlings, such as Camelina sativa,
Trifolium repens, Spergula arvensis, Panicum miliaceum and Zea
mays, while seedlings of Solanum tuber osum, Linum usitatissi-
mum, Papaver somniferum, Brassica napus, Ornithopus sativus,
Onobrychis, Pisum, Hvrdeum vulgare, Triticum vulgare and Avena
sativa were not attacked.

DeBary made a comprehensive study of the sexual stage.5 Py-
thium equiseti Sadebeck, is in his opinion the same species. P.
equiseti was first described by Sadebeck6 in 1874 from prothallia
of Equisetum arvense, and in farther studies7 it was shown that
not only did it occur in potatoes affected with Phytophthora infes-
tans* but that healthy potatoes could be inoculated with it. Py-
thium autumnale Sadebeck which grew in young plants of Equi-
setum palustre and E. limosum, produces oospores which develop
parthenogenetically. Fischer9 places this in P. debaryanum, A
plant found in Lepidium sativum, and in Beta and Sinapis by
Lohde,10 was described by him as Lucidium pythioides and from

sBeitr. z. Morph. u. Phys. d. Pilze, IV. 1881.

6 Ueber einen der familie der Saprolegniaceen angehorigen Pilze in dem
prothallien des Ackerschachtelhalmes. Sitzungsb. d. Bot. Ver. d. Prov.
Brandenberg, 116-122, 1874.

7 Neue Untersuchungen iiber Pythium equiseti. Sitzsungsb. d. Gesells.
naturf. Freunde z. Berlin, V. 21, 1875.

8 Ueber Infectionen welche Pythium-Arten bei labenden Pflanzen hervor-
bringen. Beibl. z. Tageb. d. 49 Vers. deutscher naturf. u. Aerlze. 100, 1876.

9Rabenhorst's Krypt. Flora. Pilze, IV, 404, 1892.

10 Ueber einige neue parasitische Pilze. Tagebl. d. 47 Vers. deutscher
Naturf. u. Aertze, 203, 1874.

246 BULLETIN 94.

the description there is little doubt that it is the Artotrogus de-
baryanus. L. circumdans described by the same author in a fern
prothallium" develops only in the margin of the same, producing
short conidiophores and zoosporangia with 4-8 zoospores. Fis-
cher12 also includes this with P. debaryanum Hesse, as well as the
Saprolegnia schachtii^ described by Frank in the thallus of the
liverwort Pellia epiphylla. Zoospores were not seen and oogonia
only rarely, the plant being usually sterile.

A number of these are probably rightly referred to Artotrogus
debaryanus (Hesse). Unfortunately these plants cannot well be
preserved for study in their several stages and in most of the cases
probably no specimen of any stage has been preserved, so that it
would be quite impossible at the present time at least to speak
with any feeling of certainty on the proper disposition of these
forms. There is need of a thorough and comprehensive study of
the species of the genus, and considerable uncertainty will probably
exist as to the proper disposition of some of the above species
until they can again be found and critically studied.

The fungus has been several times reported in this country, and
many notices of damping off have been made without, probably,

" Ueber einige neue parasitische Pilze. Tagebl. d. 47 Vers. deutscher
Naturf. u. Aertze, 203, 1874.

"Rabenhorst's Krypt. Flora, Pilze, IV, 404, 1892. 4 Ibid.

*3 Notes on the fungus causing damping off, etc. Trans. Mass. Hort. Soc.
I. 1891.

Explanation of Plate I. Artotrogus debaryanus (Hesse).

Figs, i, 2 and 3, different stages in fertilization ; a antheridium, oog. oogon-
ium, e. c. egg cell, gon. gonoplasm, oosp. oospore.

Figs. 4 and 5 intercalary oogonium with stalk antheridium (s. a) and
branch antheridium (b. a.), in 4 with gonoplasm separated from the peri-
plasm, and in 5 fertilization complete.

Fig. 6 terminal oogonium with stalk and branch antheridium.

Figs. 7 and 8 different stages in development, and fertilization, of sexual
organs ; b in 7, oogonium before the formation of the egg cell.

Fig. 9 oogonium with stalk antheridium (a) which has fertilized the egg
cell, and branch antheridium (b) from another hypha than that which bears
the oogonium. In this branch antheridium the gonoplasm has separated, and
the fertilization tube has formed, but fertilization took place from the stalk
antheridium first and the wall of the oospore prevented the use of the
gonoplasm from the branch antheridium.

All the figures drawn with aid of camera lucida and magnified 50 times more
than the scale. Scale — i millimeter.

l.—Artotrogus debaryanus (Hesse).

\\.-Artotrogus intermedius (deBary).

DAMPING OFF. 247

any serious attempt to determine the species. T. W. Galloway
from a careful study determined it from seedlings of Cilia, Viscaria
Lobelia, etc., in the Botanic Garden of Harvard University. He
did not however observe the zoospores. Humphey14 also carefully
determined the species, but does not describe the zoospores.

DAMPING OF PROTHALLIA.
Artotrogus intermedius (deBary).

This species was first noticed in fern prothallia growing in the
botanical conservatories of Cornell University in the month of
February, 1894. The affected prothallia were quite soft, limp, and
darker in color than the healthy ones. Some were placed in water
on a glass slip and kept in a moist chamber. The following day
the fungus had grown out of the prothallial tissue and had ex-
tended a considerable distance over the slip. The mycelium is at
first non setate and contains granular protoplasm which is present
in minute irregular masses, having in the larger threads much the
appearance of the protoplasm in some mucors, and in some cases
well marked and strong currents of the protoplasm have been ob-
served, which resemble the movement of the protoplasm in these
plants.

The threads branch monopodially, the extent of the branching
depending, to a certain extent on the amount of the vegetive
growth. The threads put out in the water from the prothallia
may be quite long and possess primary and secondary branches
before condia are developed to any great extent. The conidia are
developed at the ends of the main threads or their branches, the
hypha swelling at the end into a rounded body several times the

•* 8th Ann. Kept. Mass. State Agr. Exp. Station, 220, 1890.

Explanation of Plate II. Artotrogus intermedius (deBary).

Figs. 10, n, 12, 13, conidia developed in chains.

Figs. 14 and 15, conidia borne in a manner resembling the conidial fructi-
fication in Phytophthora.

Figs. 17-23, different stages in the development of the zoospores.

Fig. 24, free zoospores with a cilium at each pointed end, passing into
amoeboid movement and becoming divided into oval unciliated zoospores.

Fig. 1 6, intercalary conidium.

All the figures from camera lucida drawings and magnified 50 times more
than the scale. Scale i millimeter.

248 BULLETIN 94.

diameter of the thread itself. In other cases the thread may de-
velop a conidiutn while it is still quite short and the growth of the
thread in length practically cease. In other cases the conidia are
developed at the ends of the primary or secondary branches as
well as at the end of the main hypha. Where the conditions are
not favorable for the rapid growth of the vegetative portion of the
plant, sometimes the conidia are developed more profusely and
rapidly so that they are many times produced in chains. Fre-
quently these are in nearly straight chains, or they may form a
curve, or again a short and close spiral so that they are held close
to the point of origin in a small head.

The conidium may be spherical or broadly apiculate at the
proximal end or more minutely apiculate at the distal end. Some-
times there is no enlargement of the fruiting thread at the point
of origin of the conidium, but very frequently, and in a majority
of cases which I have observed where they are grown in water,
there is an oval enlargement of the hypha with a minute apical
sterigma which bears the conidium. Where there is quite rapid
growth of the fungus the hypha grows onward pushing the re-
cently developed conidium to one side but not always freeing it,
and soon bears another conidium in like manner. This continues
so that several conidia may be borne at short intervals on the
same branch, and the successive points of the origin of the conidia
are not only marked by the attached conidia but by the oval en-
largements on the branch. The appearance is thus in many
cases very much like that of the conidiophores of Phytophthora,
and deBary has called attention to the same fact. Many of the
conidia become free.

Early in April of the same year cultures were again started on
glass slips in water. A preparation was started Tuesday after-
noon, April 10, at 3 p. M. At 6 P. M. considerable growth had
taken place and several conidia were developed. At 9 P. M.
another examination was made and quite a profuse growth was
present and numerous conidia or zoosporangia.

At 9 A. M., Apr. u, there were many free conidia and zoospor-
angia and the culture abounded in the form of fructification which
so closely resembles Phytophthora. Fresh water was now added
to the preparation, a cover glass placed upon it for the purpose of
studying it with the high power of the microscope and for obtain-

DAMPING OFF.

249

ing camera lucida drawings. After making several sketches of
desired objects one zoosporangium was discovered emitting the
protoplasmic vesicle preparatory to the differentiation of the
zoospores. When the eye first fell upon it the object was in the
phase represented by Fig. 18. Soon the protoplasm had all passed
through the short tube and was collected in a rounded vesicle at
the end. There was a slight differentiation of the protoplasm at
the time of the passage, but it was little marked. The differenti-
ation became more and more marked showing that the mass was
dividing into ten to twelve polygonal bodies. The surface of the
forming zoospore next the wall of the vesicle, or the periphery, is
the longer, and at the middle of the outer surface of the object
there soon appears a depression which gives each a curved appear-
ance. This form becomes more and more marked and now move-
ment begins, which first appears as a kneading of the entire mass,
and as they become more and more sharply differentiated each
young zoospore produces an oscillatory movement with its center
nearly stationary, the movement of course much restricted by the
surrounding vesicle. As they assume more distinctly the curved
appearance there is developed from each end of the zoospore a
cilium by the lashing of which the movement becomes more vio-
lent and results soon in the release of the swarmers when they
suddenly dart away.

The movement is now a complex one. The oscillatory move-
ment is more marked with a tendency in many cases to produce
figure of 8 cycles, which is combined with a jerky progressive
movement in the direction of the longitudinal axis. Frequently
when they come in contact with some object larger in size, they
simulate to some extent the movements of a paramsecium along
some object in the water.

The form of the mature zoospore is broadly fusoid, inequilateral
with pointed ends which terminate in a long cilium. After five
to ten minutes the movement of the swarm spores becomes slower
and finally it nearly ceases and the body undergoes plastic move-
ments resembling somewhat that of an amoeba as represented in
Fig. 24. At first this amoeboid movement is irregular but after a
few minutes it assumes a definite character which tends to cut
the organism into two parts. This progresses until complete

250 BULLETIN 94.

fission results in the formation of two zoospores which are oval in
form with the ciliutn attached directly at the smaller end.

This peculiarity in the development of the zoospores is one
which has not heretofore been recorded except in a preliminary
paper by the writer.15 The species was at that time studied along
with the seedling fungus, A. debaryanus (Hesse), and as this is
reported as occurring also on fern prothallia ( Todea africana} the
species now under discussion was then supposed to be the same,
and to this species it was doubtfully referred. But the develop-
ment of the conidia is very different from that described for any
other species of this genus resembling that of Phytophthora as
stated above.

It cannot therefore at the present time be said with certainty
that the zoospore formation in Artotrogus debaryanus is the same
as that found for A. intermedius, though what evidence we al-
ready have on the subject might be interpreted to support that
view of the case.

Where the soil is kept very damp and the air of the house is
quite humid the prothallia are apt to be overrun by certain algae
which choke the prothallia, shut out the air and light, prevent
their proper development and frequently cause them to be com-
pletely sterile. Many of the prothallia are thus killed, sometimes
entire beds or pots of them. A very common alga which I have
several times observed is a variety of Hormiscia flacdda (Kuetz.)
Lagerh. Species of Oscillatoria are also frequently present and
produce a like injury.

If the pots or vessels in which the prothallia are grown are
rested on sphagnum a layer of which can be placed in the bottom
of the wardian case, and after the young prothallia have started,
all of the watering be applied through this, the prothallia will do
much better than if surface watering is practiced and far better
than where the pots are rested in a vessel partly full of water.
The air of the wardian case or of the house should not be kept too

damp.

NOTE ON THE GENUS ARTOTROGUS.

Hesse who first described Artotrogus debaryanus16 (Pythium de-

15 Preliminary note on the swarm spores of Pythium and Ceratiomyxa,
Bot. Gaz. XIX, 375, 1894.

16 Pythium debaryanum, etc. Halle, 1874.

DAMPING OFF. 251

baryanum Hesse) says as stated above that the zoospores are oval
and provided with onecilium. Pythium equiseti11 Sadebeck which
is generally considered to be the same plant, possesses two lateral
cilia according to the descriptions, and deBary only says that the
zoospore formation takes place in the oft described way.18 In
Artotrogus proliferus^ (deBary), the author was unable to deter-
mine whether the zospores were uniciliate or biciliate. In the
vesicle they are figured as reniform, but the ultimate zoospores
are described as oval, one end being narrower than the other.
Double zoospores were also described which possess two light
spots instead of one. These ultimately divided, but before
division according to the author, the double zoospore was like that
of an organism controlled by two opposing wills. This was not
the case with the biciliated zoospores observed by myself in Arto-
trogus intermedius, until amoeboid movement was beginning
after a period of swarming, and when fission is about to take place.
Possibly deBary observed the "double" zoospores just at that
time.

(In Artotrogus pyihiodes" (R. et C.) the zoospores are described
and figured as biciliate one cilium attached at each pointed end
of the zoospore exactly as I have found in the case of A. inter-
medius. But in A. pythiodes the authors say that the zoospores
absorb the two cilia, round off and germinate, i. e. they do not
divide, if the observations are clear on this point. This species
was found on leaves of Wolffia mitchellii.

Other species of the genus are as follows. A. hydnosporus*1
Mont, in potatoes and in dead seedling plants: 2Z A. ferax (deBary)
in dead insects and in dead seedlings in water. A. megalacan-
23 deBary in dead seedlings and parasitic in prothallia of Todea

17 Untersuchungen iiber Pythium equiseti,Cohn's Beitr. z. Biol. d. Pfl. III.
117.

l8Zur Kenntniss der Peronosporeen, Bot. Zeit. XXXIX., 524, 1881.

'9 Pythium proliferum deBary, Pringsh. Jahrb. f. wiss. Bot, II, 182, 1860.

^Roze et Cornu, sur deuz nouveaux types generiques pour les Families des
Saprolegnees et dess Peronosporees, Ann. d. sci. nat. Bot. ser. 5, II. 72, 1869.

21 Montague, sylloge, etc., p. 304, 1845.

22 Bot. Zeit. XXXIX., 562, 1881.

23 Beitr. z. Morph. u. Phys. d. Pilze. IV., 19, 1881 ; Bot. Zeit. XXXIX.,
578, 1881.

252 BULLETIN 94.

africana. A. proliferus"' (deBary) saprophytic on dead seedlings
and insects in water ; A. vexans2* (deBary) in dead seedlings and
in diseased potatoes ; A. anguillulae-aceti* (Sadebeck), parasitic
in Anguillula aceti ; A. sadebeckionus (Wittmack) producing
epidemics of diseases in lupines and peas. Several other species
have been impectly described.

A POTTING BED FUNGUS NEW TO AMERICA.
Completoria Complens Lohde.

This is an organism which is parasitic upon fern prothallia
grown in forcing houses. It has been known in Europe for sev-
eral years but was first found in this country during the winter of
1893-4, in the botanical conservatories of Cornell University,
while studying the rotting of prothallia induced by Artotrogus in
termedius (deBary), described in a former paragraph of this paper.
Ultimately the prothallia decay but the first signs of disease when
caused by this parasite alone is the appearance of a yellowish or
yellowish brown color imparted by the prothallia as they lie on
the soil of the pot or bed. The prothallia are so small that
usually the color appears to reside in the entire prothallium when
seen by the unaided eye. When examined by the aid of a
microscope, however, unless the prothallium is in the last stages
of the disease, the decay will be seen to be confined to " spots."

These spots vary in color from a yellowish green to yellowish
brown, deep brown and finally blackish, dependent on the phase
of the injury to the cell and its contents. At first the injury is
confined to single cells either near together or far isolated, on the
margin of the prothallium or at any point over its surface.

When the trouble is well advanced and there are numerous cen-
ters of the disease, as frequently happens, the prothallium will
present a checkered or mosaic appearance, the different pieces of
the mosaic being colored with the various shades of color detailed
above. It also presents at this time quite a ragged appearance
because many of the cells are dead and the disintegration of their
contents makes holes in the plant and rifts in its edges. A short

2*Pringsh. Jahrb. f. wiss. Bot. II., 182, 1860.

2sjour. Bot. V.,ii9, 1876.

26 Bot. Centralbla. XXXIX., 318, 1887.

DAMPING OFF. 253

note on the occurrence of this fungus in the United States was
published by the writer in the Botanical Gazette for November,
1894. It is a very interesting fungus from its very simple struct-
ure, its peculiar form, mode of development, and as a plant para-
site, from its being a member of the Entomophthoreae, which are
almost entirely parasites of insects.

The vegetative body of the fungus is a more or less compact,
grape like, or botryose cluster of oval or curved hyphal branches
originating from a common center, and presenting on the surface
a series of convolutions formed by the external hyphal branches
lying close together over the surface. This vegetative body lies
within a single cell of the prothallium, sometimes completely fill-
ing even quite large cells, while at other times the body may be
smaller especially in smaller cells of the prothallium, where it
sometimes consists of only a few hyphal branches closely curved
upon their parent cells. These hyphal branches vary from 7 ^ to
15 //. in diameter or may even be of a greater diameter, and are
one and one-half to two times longer. When the plant body in a
single cell becomes mature it may spread to the surrounding cells
by certain of the external hyphal branches putting out a slender
germ tube which pierces the adjacent intervening wall. This is
done by the tube of the hypha excreting a substance which dis-
solves the cellulose of the wall making a small minute pore and
at the same time turning the adjacent portions of the wall brown
in color. The wall of the slender thread which squeezes its way
through this opening is also colored brown, and this color is fre-
quently extended to the slender portion of the thread or tube, in
which the protoplasm passes or migrates to the center of the cell
as shown in figure 44.

When it has reached the center of the cell lumen the free end
enlarges and forms a rotund body which finally becomes oval.
At this time it is about 15^ to 25^ in diameter, with quite coarse-
ly granular protoplasm and with one or more large vacuoles. By
this time also all of the protoplasm from the original cell has
moved into this oval body in the center of the cell, leaving behind
only the wall of the slender tube by which it gained entrance and
which is still connected with the wall of the living organism.
This old wall as well as the wall of the prothallial cell where the
organism entered becomes brown in color soon after the proto-

254 BULLETIN 94.

plasm has passed through into the center of the cell of the host.
From the free and smaller end of this oval cell a short protuber-
ance grows curving to one side usually rather close to the side of
the parent cell. Sometimes this branches quite soon in a dichoto-
mous manner and the two short cells curve in opposite directions.
If dichotomy does not occur at the beginning of the protuberance
another branch arises soon from the original cell or from the
branch. These protuberances become enlarged at a very short
distance from their origin forming oval cells. These in like manner
produce short branches, and the process continues until a botryose
or convoluted mass of cells is developed which eventually fills the
cell of the prothallium, and the elements of the botryoid body be-
come angular from mutual pressure. The wall now becomes
brown in color and the glomerule appears to be mature.

In this condition if these hyphal masses are teased out from the
cell of the prothallium and kept on a glass slip in a small amount
of moisture germination soon takes place. Hyphal masses so
teased out from the prothallium and placed under the above con-
ditions at 5 P. M. on Feb. 22, 1894, and kept at the ordinary room
temperature during the night, the temperature falling somewhat
below that of the day (the temperature was 70° to 80° Fahr. , up
to midnight and fell 50 toward morning and rose to 66 at 9 A. M.).
At 9 A. M. Feb. 23d, the preparations were examined and the
mature hyphal masses were germinating. In some cases the germ
tubes were 5oo/u, to yoo/x long and all the protoplasm had moved
out in the distal half of the tube (fig. 42). In germination under
such circumstances a protuberance arises from one of the individ-
ual cells of the glomerule and extends soon into a tube the diame-
ter of which is about io/x. As the tube extends in length the pro-
toplasm gradually disappears from the parent cell and passes into
the tube. As the tube continues to elongate the protoplasm con-
tinues in the distal portion and the older portion of the tube be-
comes empty, nothing remaining but the wall. There appears to
be a wall at the junction of the tube with the parent cell, if so it
is formed after the protoplasm has passed into the tube.- When
the tube has become considerably elongated so that there is an
empty portion from 2oo/u, to 5oo/x in length there appear what seem
to be transverse septa, or it may be the remains of a portion of the
protoplasm situated in a thin transverse sheet in the tube. These

DAMPING OFF. 255

occur so regularly and at about 30/x. to 40^ distant that the resem-
blance to septa is very striking if they are not really septa. If
they are septa they are formed only after the protoplasm has
passed these points. It may be that the growth of the tube was
arrested for a certain length of time and the walls were formed
while it was in this quiescent condition, or the growth of the tube
may be naturally periodic. The protoplasm is coarsely granular,
presenting here and there rather faint vacuoles, but there are so
far as examined, no septa separating the protoplasm into distinct
portions. The course of the tube is slightly sinuous, and also in
an ascending position as the glomerule lay on the glass slip.
Perhaps this was for the purpose of emerging from the water.
After an examination the cultures were returned to the moist
chamber.

While the fungus is progressing through a prothallium when
one of these spore balls becomes mature, some of the cells lying
adjacent to healthy cells of the prothallium germinate and grow
directly into the new cell host. In doing so the germ tube is very
much smaller since less energy is expended in making the per-
foration through the wall. After emerging from the wall in the
new host cell the tube does not enlarge to the size of the tube
when germination takes place in water on the glass slip, but re-
mains about the same size as that of the perforation in the wall,
until it reaches the center of the cell lumen where it enlarges into
a rotund body as described above. Here it soon grows into the
botryoid hyphal mass again. Other cells may germinate and
course for a considerable distance over the surface of the pro-
thallium and enter new host cells quite distant from the
hyphal mass, but this has not been observed. In some cases
more than one cell lying quite close to a new host cell will ger-
minate and grow into the same. From the observations thus far
made I should judge this to be quite common but not general.

The first ovoid portion of the mycelium in the center cf the cell
of the host is considerably larger than the curved branch which
develops at its apex and frequently larger than any which follow.
The more slender form of these branches and the close apposition
of the branches to the primary enlarged ovoid portion suggests a
striking resemblance to an oogonium and antheridium. Thus far
have not seen any conclusive evidence that these organs are I

256 BULLETIN 94.

present. However, frequently the conditions are favorable for the
development of another form than the purely vegetative portion
of the plant, and either simple resting spores are developed, or if
sexual organs are present, then oospores. The number of resting
spores varies from one to ten or even twenty in large prothallial
cells where the botryoid fungus is well developed. The resting
spores occupy the central portion of the mass and are surrounded
by the smaller and terminal cells of the plant which now are
empty. The resting spores are rounded, sometimes oval, in form
and when mature are bounded by a very thick wall consisting of
three coats which are smooth, but sometimes appear roughened by
the closely cohering cell walls of the collapsed surrounding ter-
minal portions of the botryose mycelium. The portions which
become resting cells are always the larger and central portions.
They are much larger at the time of the formation of -the resting
spores than when the fungus is in the vegetative stage, and since
at first there appear to be no cell walls intervening it would seem
that their increase in size came chiefly from the outer and smaller
cells giving up to them their protoplasmic contents rather than
that the additional nutriment came from the cell of the host which
by this time is nearly exhausted. However, this point was not
determined. The wall of the young resting spore is at first very
thin and the protoplasm finely granular. The mature resting

Explanation of Plate III. Completoria complens Lohde.

Figs. 26-30 different plants with mature resting spores showing the vari-
ation in number developed in a single plant ; the resting spores surrounded
by the empty peripheral cells of the plant, which may have developed conidia,
or some of them entered adjacent cells of the prothallium, or possibly some
of them fed the developing resting spores.

Figs. 31-32, younger stages in the development of the resting spores.

Fig. 34, plant developing resting spores at the center and a conidium from
one of the peripheral cells.

Fig. 35 conidium germinating ; 36, 37 and 39 germinating conidia with the
germinal vesicles or proembryos developed from each one.

Fig. 40 germinal vesicle or proembryo developing the minute entrance
tube which pierces the wall of the cell of the prothallium, 38 showing the
entrance tube complete and the protoplasm having migrated to the center of
the cell where the rotund body is formed, 41 branching of young plant in
cell of host.

Drawn with aid of camera lucida and magnified 30 times more than the
scale. Scale, i millimeter.

III. — Completoria complens Lohde.

PLATE \\.-Completoria complens Lohde.

DAMPING OFF. 257

spore presents a very coarsely granular protoplasm the granules
rounded in form and closely packed together.

Propagation also takes place by the production of non-motile
Conidia from monosporous sporangia.

The conidia are oval or broadly obovate, colorless cells, with a
thin wall and measure from 15^. to 25 , u. in diameter. In germi-
nating, unless they are lying entirely immersed in water or in an
abundance of a water which may be on the surface of the pro-
thallium or on the soil, they do not form a mycelial tube directly.
A very short tube is formed and into this the protoplasm migrates
and causes the end of the short tube to swell out into an oval or
oblong vesicle or the vesicle may be separated from the conidium
by a constriction. This phase reminds one of the formation of
the zoospore vesicle in the species of Artotrogus. But the forma-
tion of this tube and of the vesicle does not take place so rapidly
as in Artotrogus, and the form of the vesicle is quite different and
varies considerably in form as well as in size, but the most marked
difference is that there is a firmer covering which appears to be
in the nature of a well defined wall around the protoplasmic
vesicle, while in Artotrogus there is only a protoplasmic mem-
brane. Here the analogy ceases for zoospores are not formed.
This cell is a germinal vesicle or proembryo, and from this pro-
embryo arises the slender tube which pierces the cell of the pro-
thallium and permits the parasite to enter. If the conidia are lying
in an abundance of water they will germinate and produce a tube
five to ten times the length of the diameter of the conidium.
This I have several times observed, but in no such case have I
observed the germ tube to enter a cell of the prothallium. Leitgeb

Explanation of Plate IV. Completoria complens I«ohde.

Fig. 42 botryose cluster of plant body after being placed in water, the per-
ipheral cells germinating and forming long tubes.

Fig. 43 plant body, some of the central cells forming resting spores, and
some of the peripheral ones developing conidia.

Fig. 44 plant body in one cell of the host, the peripheral cells developing
tubes which penetrate adjacent cells of the prothallium.

Fig. 45 two young plants in one cell of the host having entered from an
adjacent cell, early stages in the branching and development of the botryose
plant body are shown.

All figures drawn with aid of the camera lucida and magnified 30 times
more than the scale. Scale, i millimeter.

258 BULLETIN 94.

states that in such cases which came under his observation the
conidium only developed a short tube and then soon died.

The conidia possess a prominent apiculus which in develop-
ment is directed toward and rests partly in the stalk of the spor-
angium. The sporangium develops from some of the superficial
cells of the botryose body, but so far as I have examined from
cells which are larger than the usual external cells. The cell
begins growth in an upright position or away from the moisture
and appears very much like an ordinary vegetative thread which
is produced when the plant is immersed in water except that it is
greater in diameter. When 6o/j- to 8o//- in length the end becomes
enlarged and the protoplasm collects into the forming sporan-
gium. While the sporangium is forming the protoplasm is more
coarsely granular at the base, while at the terminal portion it is
more hyaline, giving the appearance of quite large and rather
numerous vacuoles. When the spore is mature it is ejected with
considerable force in much the same manner as the spores of the
Bntomophthorae.

The aerial development of the sporangia instead of aquatic is in
correspondence with the nonciliated condition of the conidia.
One case which came under my observation shows clearly the
necessity for the aerial development of the sporangia in the forma-
tion of the conidia in this plant. In mounting an affected pro-
thallium in water for examination I discovered a partly formed
sporangium which projected out into the cavity of an old and
emptied ruptured cell. In the growing condition of the prothallia
in this case they were somewhat crowded so that they stood more
or less erect. The sporangium then in growing also in an erect
position away from the moisture would be directed into the empty
cell above. Placing this prothallium in a horizontal position on
the glass slip in a small quantity of water would immerse the
sporangium in the water, or partly so. All of the water was then
drawn off except j ust a sufficient amount to prevent the prothal-
lium and fungus from drying and the preparation was placed in
a moist chamber in order that from time to time it might be ex-
amined to watch the development of the sporangium. This stage
of the sporangium is represented in figure 43. No farther devel-
opment of this sporangium took place. But just at the base of
the stalk another one began to be thrown up in a position per-

DAMPING OFF. 259

pendicular to this prostrate one. As the new one increased in
height the old one gradually lost the protoplasm both from the
forming sporangium and the stalk. In the course of 4 to 5 hours
the sporangium was mature and the conidium ejected, when the
sporangium and stalk collapsed and remained as a flabby mem-
brane attached to the wall of the old stalk and sporangium which
was still in the water and which still remained intact.

The conidium is capable of germinating immediately when
there is sufficient moisture and the behavior seems to be mani-
fested in three different ways according to the amount of moisture,
or in some cases perhaps according to the proximity of the host.
If the spore is entirely immersed in water a long slender germ
tube is put forth similar to the tube which is emitted from the
terminal cells of the botryose body of a vegetatively mature plant.
Where less water is present the conidium germinates by develop-
ing a germinal vesicle, or proembryo as described above.

From the inner face, the one lying next the prothallium cell,
of the broader end of the proembryo, a minute tube is thrust out
which pierces the cell wall of the host and grows out to the cen-
ter of the cell lumen where in the ordinary way it enlarges into
the first ovoid body of the new plant (fig's. 38, 40). In other
cases probably, where there is still a less quantity of moisture,
the tube from the germinating spore is directed upward or away
from the host and becomes a sporangium with a very short stalk
or only the short narrowed end of the sporangium which serves
as a stalk. Before this conidium is ejected from this secondary
sporangium if it be immersed in water, the protoplasm will grow
out into a long slender germ tube. If it were only partially
immersed it might as in the case of the primary sporangium noted
develop a new sporangium. In the case of the primary sporan-
gium which was immersed in water and which developed a new
sporangium at the base of the old one, as described above, the
base of the stalk was not entirely immersed.

As stated above the primary sporangia in the cases observed
developed from some of the larger of the external cells of the
cluster. In one case this took place while the inner cells
were developing resting spores (fig. 34). It may be possible that
the sporangia are always developed from somewhat larger and
richer cells of the periphery but more likely others of the cells can

26o BULLETIN 94.

develop sporangia when the conditions of the environment, which
have not all been determined, are such as to produce this tendency
to fruit in the organism.

I have found the fungus in the prothallia ofAspidmm (Cyrtomi-
um) falcatum, Pteris argyria and Pt. cretica.

It was first described by Lohde27 and was later more thoroughly
studied by Leitgeb, 28 who grew it in a large number of fern pro-
thallia.

A NEW CUTTING BED FUNGUS.
Volutella leucotricha Atkinson.

April loth (1894) two cuttings, in the botanical conservatory,
of carnations which were damping off were called to my attention.
These were placed in a moist chamber expecting to obtain the
sterile fungus or an Artotrogus. Two days later, i2th, the stems
were well covered with a fungus which formed elevated stromata,
whitish in color or with a slight tinge of flesh color. With a
hand glass the stroma was seen to be surrounded by several setae,
which, however, did not present at the time a dark color as is the
case with the common carnation anthracnose, Volutella dianthi
(Hals.). At the time it was supposed that this lack of color in the
setae might be due to the growth. Sections of the stromata showed
the structure of a Volutella, but the conidia were considerably
smaller than those of V. dianthi and the setae were quite different
in form as well as in color. They taper but little toward the free
ends, are quite blunt at the ends and usually more times septate.

At my request Mr. R. H. Pettit, a student in my laboratory,
made a separation of the fungus for me by the agarp late method.
The first trial was successful and in a few days the colonies of the
Volutella were visible to the unaided eye, the conidia having been
kept watch of during the stage of germination and the formation
of the colonies. The growth of the colonies is quite different
from that of the V. dianthi as well as the development of the
fruiting hyphae, and there was no longer any doubt that it was

*7 Ueber einige neue parasitische Pilze. Tagebl. d. 47 Vers. deutscher
Naturf. u. Aertze, 203, 1874.

88 Completoria complens Lohde, ein in Farnprothallien schrnarotzender
Pilz. Sitzungsb. d. math, naturw. Klasse d. K. Akad. d. Wiss. LXXXIV, I,
288, 1881.

DAMPING OFF. 261

a different species from the V. dianthi, and the name V. leucotricha
is here proposed for it.

Pure cultures were then started on bean and vetch stems and in
a few days the characteristic stroma with the setae were developed
in profusion on the surface of the stems. With the conidia from
one of these cultures pure dilution cultures were made on April
2oth. Instead of pouring a few drops of the first dilution into the
second and from this into the third as I usually do with fungi
having large conidia, the second and third dilutions were made
by transferring with a double and twisted platinum needle. Plate
number i and 2 were sufficiently separated for the study of colony
characteristics and for photographing natural size. The colonies
grow rather slowly and the plate No. 2 was ready for photograph-
ing on the 25th, and No. 3 on the 27th. In No. 2 the colonies
were quite numerous and consequently rather small, from 4-6
mm. in diameter, while those in plate No. 3 where there were
only 6 colonies were on the 2yth 10 mm. in diameter. The col-
ony steadily develops a thin and nearly circular weft marked by
numerous fine radiating lines which because of the exceeding
thinness of the weft are visible over the entire colony as it ages.
There are quite regularly more dense radiating lines caused by
the overlapping of certain radiating areas, and the margin shows
a tendency to form roundish angles. The growth is quite sensi-
tive to periodic changes in temperature which occur between
night and day, as shown by the several concentric lines which are
quite pronounced on the colony. At the center of the colony
there is developed quite a compact stroma which is very much
like that on a more solid substratum, like the stems of the vetch
or bean. This stroma may be quite extensive and irregular in
outline with a few outlying smaller and scattered ones, or there
may be quite a large number of them at the center of the colony,
the larger ones of course nearer the center and the smaller ones at
the periphery. These individual stromata are so far like those
developed in solid substrata, either in nature or culture tubes,
that they are margined with the characteristic setae. A photo-
graph of several of these growing in the agar in a Petrie dish is
shown in fig. 52, plate VI, left upper corner. The photograph
was taken from directly above and is magnified about 60 diameters.

In a few days after the appearance of the colonies the basidia

262 BULLETIN 94.

begin to develop. Some of them and probably the first ones are
prostrate and wholly or partly immersed in the agar. They may
be simple, or branched, when the branches may be opposite, or
irregular, and in some cases the branches are assurgent, when
most of them are thrown to one side. There is a strong tendency
for the threads of the mycelium to assume a moniliform appear-
ance by the swelling of the short cells thus producing a strong
constriction at the septa. This tendency to a swelling of the cells
of the mycelium is also shown to some extent in the basidia.
Quite early many of the fruiting threads become erect and branch
several times, the ultimate branches forming the basidia. The
branches and the basidia are frequently opposite or whorled and
when standing alone simulate very well the conidial fructification
of a Vertidllium. For some time the conidia are held in chains
as they are developed successively on the same basidium. When
moisture is sufficient, and this is usually the case in the Petrie
dish, the capillarity of the film surrounding the conidia pulls
them from the concatenate position and they are gathered into a
globular head appearing as if they were developed in the form of
a Mucor. Very soon at the center of the colony by the develop-
ment of numerous fertile hyphae very closely, a true stroma is
formed, and the conidia are held by capillarity in great masses
upon the summit of the stroma.

April 24th a cell culture was prepared in a drop of nutrient agar
at 5 P. -M. On the following day the conidia were germinating and
a group of them was photographed (46, Plate V. upper left corner).
The spores here at this time were 4-5 // in diameter. The germ
tubes are quite sinuous and at this age (17 hours from time of sow-
ing) were 15 /' to 25 P. long, and about 2 P. in diameter. In the ger-
minating spores are a few, 3 to 5, small and very strongly refringent
granules in the hyaline and homogenous protoplasm, and are quite
well shown in the photomicrograph. On the following day when
the culture was 40 hours old another photograph was taken (fig.
47). By this time many of the conidia showed the development of
three tubes, and the tubes were now quite long. In some cases the
hyphae coming in contact, anastomose, one of these conditions
being shown in the photomicrograph. One day later several of
the conidia showed still other tubes so that in time two to several
tubes may arise from a single conidium. The anastomosing in

ft

«•* ' \

PI,ATB V. — Volutella leucotricha Atkinson.

PI,ATE VI. — Voluletla leucotricha Atkinson.

DAMPING OFF. 263

some cases is quite common. In this cell culture where the layer
of nutrient agar was quite thin and the conidia numerous, fruit-
ing did not take place very abundantly. In many cases the
basidia are directly connected with the conidium, and in other
and a majority of cases the basidia are developed from the hyphae
at a variable distance from the conidium. The basidia under
these circumstances are usually simple, terete and at the apex
bear several conidia, which because of the rather large per cent,
of water in the medium soon free themselves from the point of
their origin and rest at one side. In a few cases the basidium is
branched, or the fruiting hypha may bear lateral or opposite
branches, and the terminal portion act as a basidium also. In
this cell culture there was not the tendency for either the mycel-
ium or the basidia to become swollen or enlarged. Two photo-
micrographs were taken of the conidium production in the cell
culture, one showing the development of a basidium directly from
the conidium (50 lower left) and one with two basidia near each
other on a single thread of the mycelium (48 middle right).

In order to study the separate conidiophores, or fruiting hyphae
recourse was had to the dilution culture, No. i, in the Petrie dish.
The conidia being so numerous in this dilution caused the devel-
opment of numerous colonies in quite close proximity, and the
fruiting was necessarily more scanty and a less tendency to the
development of the stroma so characteristic of the fungus on solid
substrata, or in the agar where they were not so crowded. There
were therefore many scattered and independent fruiting hyphae or
conidiophores. By placing a thin cover glass over portions of the
plate these erect conidiophores were bent in a prostrate position,
and the amount of moisture was sufficient to displace the greater
amount of air so that the medium between the glass and the agar
was nearly of the same density as the agar itself, and quite satis-
factory photographs could be obtained when the subadjacent
growth of mycelium was not too dense to interfere with the entrance
of light, or to produce a hopeless confusion of threads which were
not desired. Figs. 49, 51 and 54 represent some of the conditions
of the conidiophores in this culture, which have been referred to
above. (Figs. 46-51 and 54 were photographed at an amplifica-
tion of about 600 diameters).

A portion of one of the fruiting stools which was teased out

264 BULLETIN 94.

from a culture on vetch stems was photographed with an amplifi-
cation of loo diameters and is shown in Fig. 53, Plate VI, lower
figure. The preparation was mounted in water and the conidia
which were so numerous that they would have clouded the prepar-
ation were mostly washed out. Quite a number, however, remain-
ed in the preparation, and show as minute oblong dark spots over
the field of the photomicrograph . The fruiting stool is composed
of numerous branched sporophores closely compacted together.

CANKER IN CUCUMBERS.

What is sometimes called canker in cucumbers has occurred dur-
ing the two past winters in the horticultural houses of Cornell
University. The appearance is that of a larger and deep ulcer in
the stem at the surface of the ground. It occurs on plants of
considerable size, on stems from 5 cm. to i cm. or more in diame-
ter, the vines of which are several meters long. The ulcer has a
dull brown color, the color of the external portion depending to
some extent on the amount of soil which becomes worked into it.
The tissues for some depth are soft and more or less putrid,
dependent on the stage of the disease. It may advance so far as
to cause the stem to rot off entirely, when of course the plant dies.
In other cases the plant may not be ultimately killed but the
ulcer has affected so deeply the vascular tissues as to interfere
greatly with certain physiological functions of the plant. As the
disease becomes serious the plants take on a sickly yellowish
green color and become more or less limp. It soon soon runs its
course, ending in death. During the month of December, 1894,
sections of a diseased stem were placed in water and kept as
described above for the seedling fungus, and in twenty-four hours
a profuse growth of an Artotrogus, supposed to be the common
A. debaryanus was developed. The species was at that time not
accurately determined, and at the present writing there is none of
the disease in the houses. The trouble is invited by keeping the
soil around the stems in a too wet condition, just such conditions
as favor the development of the seedling fungus. It is quite pos-
sible that another fungus to be described in a later paragraph may
also have something to do with the etiology of the trouble.

DAMPING OFF. 265

DAMPING OFF BY A STERILE FUNGUS.

Much of the trouble in the nature of damping off both in the
forcing house and in the fields is caused by a fungus which has
been under study at several different times during the last three
years, but up to the present time has refused all the encourage-
ment, which it has been possible from present experience to offer
it with the hope of inducing it to develop some characteristic
fruiting organs in order that its real nature and affinities might
thus be made known. There are quite characteristic features of
the mycelium and of certain sclerotoid bodies developed on the
mycelium, and which with a little care serve to distinguish it from
other known fungi.

I first observed it while studying the diseases of the cotton plant.
(See Bull, Ala. Agr. Exp. Station, Dec. 1892,) In the cotton
growing states it is a very frequent parasite on young cotton plants
and produces a very large percentage, so far as my observation
has gone, of what is known as " sore shin " in that section. The
trouble is caused by the fungus growing first in the superficial
tissues of the stem near the ground and disintegrating them before
it passes to the deeper tissues, in other words the fungus never
seems to penetrate far in the living tissues but " kills as it goes "
and the tissues become brown, depressed and present the ap-
pearance of the plant having a deep and ugly ulcer at the surface
of the ground. The fungus does not spread into the tissues either
above or below the ulcer to any extent, but literally eats away at
that point until it has severed the stem at the affected place or the
plant has recovered from its effects. The plants do not seem to
suffer seriously from the disease until the woody portion contain-
ing the vascular bundles is nearly or quite eaten away.

In the latter case all communication between the root and the
aerial portion of the plants is cut off and of course the plant withers
and dies. But frequently the stem may be eaten off so far that
the plant has not sufficient strength in the remaining tissue at
that point to support it and it will fall over, and perhaps if the
disease does not progress any farther it may remain fresh and
green for weeks, but it is rare that after this stage the plant re-
covers sufficient strength at that point to erect itself again.
Frequently however when the stem is nearly eaten off the disease
may be arrested and the plant completely recover from the effects.

266

BULLETIN 94.

During the winter of 1894-5, some bean plants in the horticul-
tural forcing houses of Cornell University were affected by this
disease and quite a number of them presented brown and quite
deep ulcers on the stems of the surface of the ground. A few of
the*plants went so far as not to be able to stand. Some of the
worst ones were pulled up, but others which
were quite badly diseased remained in the bed
and all gradually recovered completely. The
plants were six to ten inches in height when the
trouble was called to my attention. When the
plants attain this size the disease cannot make
such headway, but even very young plants will
frequently recover from the effects.

It is more serious when it attacks smaller seed-
lings, as radishes, lettuce, etc. Egg plants and
cabbages as well as others are known to be affected
Both the plants in seed beds in the forcing houses
have been quite seriously affected by this fungus.
Lettuce is frequently eaten off at the surface
of the ground and the plants supported by others
near may remain erect and fresh for several
days. Gradually, however, if not quickly, they wither and fall
when the fungus grows in the tissues farther as a saprophyte. If
such plants be placed in a moist chamber, it is not necessary to
place them in water, in a day or two there will be developed on
the surrounding moist paper on which it is well to place the plants,
a profuse growth of mycelium composed of whitish threads. To
be sure that these threads are those of this fungus and not those
of some mucor it will be necessary to have recourse to the micro-
scope. The most characteristic peculiarity of the threads of the
mycelium is to be found in connection with the branching. The
freshly developed threads branch freely but not profusely, they
are colorless, composed of elongated cells 9 P-II i>- in diameter and
IOO/J--200/'- in length. The protoplasm is finely granular and
contains numerous small rounded vacuoles. The branches extend
to an angle usually of between 30 and 60 degrees from the main
hypha and very near the point of attachment are a little curved
toward the point of growth of the same. At the point of attach-
ment with the parent hypha the branch is considerably smaller

55- — Sterile fungus
grown on slide
from seedling of
Centaurea candi-
dissinia.

DAMPING OFF. 267

than either the diameter of the parent hypha or the main part of
the branch, and the septum separating the protoplasm of the
greater part of the branch from that of the parent hypha is situ-
ated some distance from the latter, usually 15/1-20,* from the
main thread. This portion of the branch then, the contents of
which are continuous with those of the parent thread, is clavate in
form. Species of Botrytis will occasionally be developed in dis-
eased tissue of this kind, and sometimes develop phenomena of
damping off similar to that produced by this fungus, though much
more rarely, and the mycelium in its early stages cannot so far as
I am able to tell be differentiated from this sterile fungus. But
if a culture of the mycelium be made, in the course of a few days
or in a week, if the mycelium be that of Botrytis the conidial
stage or the clasping organs will be developed. But if it be that
of this sterile fungus no such conidial stage will be developed.

Pure cultures of the fungus have been obtained at two different
times. In the summer of 1892, from young cotton plants and
again in February, 1895, from young lettuce plants which were
damping off. It can quite easily be obtained in pure culture by
transferring some of the mycelium grown in the air of a moist
chamber, to some acidulated culture media. A very good medium
is made by placing cuttings of bean stems, 7 to 8 centimeters long,
in a culture tube and adding to this about 8cc. of water and one
drop of concentrated lactic acid. Several of these culture tubes
should be prepared, and .then sterilized in steam for two hours
per day for three or four days in succession. The bean stems
should project 2 to 4 centimeters above the liquid, and to the ends
of these the mycelium can be transferred with a flamed platinum
needle. Several transfers should be made and from portions of
the mycelium which have been previously examined to be certain
that mucors or other fungi are not present. Out of several trans-
fers, if the growth in the moist chamber has been made with
caution, a few pure cultures are quite likely to result.

Bacteria will be shut out by the acid in the medium, and if the
culture is free from other fungi in a few days the mycelium will
be visible as a silky white growth which spreads over the surface
of the bean stems growing downward over them and also outward
onto the surface of the glass tube. This growth continues to ad-
vance for several days with quite an even advance edge to the

268 BULLETIN 94.

weft. In the course of four or five days or one week, from the
time that the mycelium is visible to the eye in the culture tube,
there will appear first on the stems at certain points, and later on
the surface of the glass tube, minute white powdery looking tufts
on the mycelium. These are made up of closely and profusely
branched threads, the branching sometimes presenting numerous
and quite regular dichotomies, at other times quite irregular, and
the terminal branches profusely lobed, the lobes standing in all
directions and considerably more slender than the threads of the
mycelium, and from IO/A to 2o/u, or more in length, occupying the
distal portion of the branch for a distance from 20;; to 5<D/x,.
Another form of branching will also be present in which the
closely set branches diverge at quite strong angles and are quite
regularly constricted, presenting a moniliform appearance, and
become eventually divided into short cells. These branches be-
come more closely compacted and interwoven, forming rotund
bodies at first white and quite small but eventually 2 to 4 millime-
ters in diameter and of a brown color. These bodies are proba-
bly sclerotia.

Upon the surface of these sclerotia are diverging threads with
numerous moniliform cells which resemble chains of conidia.
These are not true conidia since they do not easily become sepa-
rated. By breaking down the sclerotia or by scraping the sur-
face many of them become separated into chains of two or three
cells or even become entirely separate. If placed in water, or in
suitable medium, they will germinate, thus functioning like
conidia.

The sclerotia have been kept for several months but in no case
has any other stage of the fungus been developed from them.

At present it cannot be correlated with any known group of
fungi but there are reasons for supposing that the sclerotia may
be the resting stage of some hymenomycetous fungus. Fre-
quently the threads become united into rope like strands and
change to a brown color.

DAMPING OFF BY VARIOUS FUNGI.

Several fungi, probably quite a large number, produce phases
of damping off at certain times while their evil effects are not con-
fined to this peculiar class of injuries. Phytophthora cadorum

DAMPING OFF. 269

(L,. et C.) Schroeter {Phytophthora omnivora deBary) was first
discovered as the cause of decay of species of cactus in forcing
houses. This fungus frequently destroys seedlings of trees, caus-
ing them to become brown and later to decay.

Several of the anthracnoses are known to produce genuine
cases of damping off while their injury is by no means confined
to this trouble. Colletotrichum lindemuthianum on bean seedlings
is a good illustration of this, as Halsted29 has already shown. The
same author points out that a Colletotrichum on cuttings of albut-
ilon, passiflora, clematis and jessamine causes them to damp off
and in some houses ruins the bulk of the cuttings in the bed,
while a Gloeosporium damps off rose cuttings.

Another anthracnose, Colletotrichum gossypii Southworth some-
times damps off seedling plants of cotton. Carnations are also
affected in the same way by Volutella dianthae (Hals).

Halsted found a Phyllosticta in one case and in another case a
a Septoria growing in the stems of decaying chrysanthemums, and
while this was the only fungus present it was not certainly deter-
mined as the cause of the trouble. According to Halsted bacteria
also cause seedlings of cucumbers to damp off.

A species of Botrytis which is very common in forcing houses
producing a variety of diseases of various plants frequently damps
off leaves and twigs of cuttings or well rooted plants. When the
houses are quite damp the fungus gains hold on the plant, prob-
ably in the axil of the leaf or branch, because the water is held
at these points for a longer time, and once well seated in the
tissue continues its work until the leaf or branch is rotted off.
Leaves of begonias and branches of roses have been so damped off
in the horticultural houses at Cornell University.

A careful inquiry would probably reveal a large number of fungi
which at times produce diseases almost if not quite identical with
damping off so far as external appearance goes.

TREATMENT.

In the treatment of this trouble especial attention must be given
to the environment of the plants and those conditions which favor
the rapid development of the parasites. These conditions are

Rept. N. Jr. Agr. Coll. Bxp. Sta. 291, 1891.

270 BULLETIN 94.

known in most cases to be high temperature accompanied by a
large moisture content of the soil, humid atmosphere, insufficient
light and close apartments, and soil which has become thorough-
ly infested with the fungi by the development of the disease in
plants growing in the same. Some excellent notes on the treat-
ment of the disease by gardeners and horticulturists are given in
the American Garden for 1890, by Meehan, Massey, Maynard,
Watson, lyonsdale, Gardiner, and Bailey, and a short description
of the potting bed fungus (Artotrogus debaryanus} by Sey-
mour. The principal lines of treatment suggested there from the
practical experience of the writers are as follows :

When cuttings are badly diseased they should be taken out, the
soil removed, benches cleaned and fresh sand introduced, when
only the sound cuttings should be reset. For cuttings is recom-
mended a fairly cool house, and confined air should be avoided in
all cases. As much sunlight as possible should be given as the
plants will stand without wilting. When close atmosphere is
necessary guard against too much moisture and keep an even
temperature. The soil should be kept as free as possible from de-
caying vegetable matter. This is a very important matter, for
several of the most troublesome of the parasites grow readily on
such decaying vegetable matter and in many cases obtain such
vigorous growth that they can readily attack a perfectly healthy
plant which could resist the fungus if the vegetable matter had
not been there to give it such a start. Soil which is dry beneath
and wet on top as results from insufficient watering by a sprink-
ler favors the disease more than uniformity of moisture through-
out the soil.

In seed beds use fresh sandy soil free from decaying matter.
Avoid over watering especially in dull weather, shade in the mid-
dle part of the day only and keep temperature as low as the plants
will stand,

he seedlings are badly diseased it will be wise to discard
them and start the bed anew. In the early stages however they
can frequently be saved by loosening the soil to dry it, and plac-
ing the pots in sunny places at such times as they will not wilt.
Some advocate sprinkling sulphur on the soil and in some cases
sulphur at the rate of one to thirty is mixed in the soil before
sowing with good effect. When the beds are badly infested

DAMPING OFF. 271

Humphrey30 advocates the entire removal of the soil, whitewash-
ing the beds, and the introduction of fresh soil.

In houses heated by steam if it were possible to have, without
too great expense, a steam chest where the pots and seed pans
which are used could be placed and the soil thoroughly steamed
for several hours it could be sterilized, and the finer and more
delicate seedlings be grown then with little danger if subsequent
care was used to not introduce soil from the beds. In testing the
virulence of the Artotrogus debaryanus (Hesse), and of the sterile
fungus, several experiments have been made by steaming pots of
earth, growing seedlings in them and then inoculating some of the
seedlings with the fungus while other pots were kept as checks,
and all were under like conditions with respect to moisture, tem-
perature, etc. The seedlings which were not supplied with the
fungus remained healthy while those supplied with the fungus
were diseased and many killed outright (see frontispiece).

CONCLUSIONS.

Damping off is caused by the growth in the seedlings or cut-
tings of fungus parasites which themselves are plants but micro-
scopic in size. The plants when affected frequently present a
paler green color. The tissues become soft at the surface of the
ground, the plant falls over and dies. No one fungus is concern-
ed even in the soft rot of seedlings. In related cases the plant
may show a brownish ulcer at the surface of the ground which
frequently increases in size until the plant is severed at this point
and then dies.

Too great a moisture content of the soil, air, high temperatures,
close apartments, and insufficient light not only favor the rapid
growth of the parasites but they also induce a weakly growth on
the part of the seedling so that it cannot so readily resist the
disease.

The parasites can grow and multiply on decaying vegetable
matter which is in the soil.

When once in the soil they can remain alive for months even
though the soil become dry or frozen.

Soil used in seed beds or cutting beds should be free from de-

3° Mass. State Agr. Exp. Sta. Bull. 402, 1891.

272 ULLETIN 94.

caying vegetable matter or care should be used that the matter
is thoroughly decomposed. Fresh sand is said to be the best for
small seedlings.

Soil in which plants have once been diseased should be dis-
carded if it cannot be sterilized by steam heat for several hours.
Fresh soil free from vegetable matter should be introduced.

Water the soil thoroughly but not to saturation and do not
water oftener than actually needed.

Keep the houses well lighted, well supplied with fresh air. Do
not have high temperatures, keep as even a temperature as pos-
sible. When the disease first sets in stir the soil about the plants
and do everything possible to dry the soil without killing the
plants or raising the temperature, keep the temperature as low as
the plants will bear. If this does not save them change the soil
and clean the beds by whitewashing them.

When cuttings become seriously diseased change them to fresh
soil, resetting only the perfectly healthy ones.

GEO. F, ATKINSON.

? I

MAY, 1913

tl3JL-fVM JCUIcl

BULLETIN 333

CORNELL UNIVERSITY

AGRICULTURAL EXPERIMENT STATION OF

THE COLLEGE OF AGRICULTURE

Department of Entomology

CONTROL OF TWO ELM-TREE PESTS

BY GLENN W. HERRICK

ITHACA, N. Y.
PUBLISHED BY THE UNIVERSITY

CORNELL UNIVERSITY
AGRICULTURAL EXPERIMENT STATION

EXPERIMENTING STAFF

LIBERTY H. BAILEY, M.S., LL.D., Director.

ALBERT R. MANN, B.S.A., Secretary and Editor.

JOHN H. COMSTOCK, B.S., Entomology.

HENRY H. WING, M.S. in Agr., Animal Husbandry.

T. LYTTLETON LYON, Ph.D. Soil Technology.

JOHN L. STONE, B.Agr., Farm Practice and Farm Crops.

JAMES E. RICE, B.S.A., Poultry Husbandry.

GEORGE W. CAVANAUGH, B.S., Chemistry.

HERBERT H. WHETZEL, A.B., M.A., Plant Pathology.

ELMER O. FIPPIN, B.S.A., Soil Technology.

GEORGE F. WARREN, Ph.D., Farm Management.

WILLIAM A. STOCKING, JR., M.S.A., Dairy Industry.

CHARLES S. WILSON, A.B., M.S.A., Pomology.

WILFORD M. WILSON , M.D. , Meteorology .

WALTER MULFORD, B.S.A., F.E. , Forestry.

HARRY H. LOVE, Ph.D., Plant-Breeding Investigations.

ARTHUR W. GILBERT, Ph.D., Plant-Breeding.

DONALD REDDICK. A.B., Ph.D., Plant Pathology.

EDWARD G. MONTGOMERY, M.A.,Farm Crops.

WILLIAM A. RILEY, Ph.D., Entomology.

MERRITT W. HARPER, M.S., Animal Husbandry.

J. A. BIZZELL, Ph.D., Soil Technology.

CLARENCE A. ROGERS, M.S.A., Poultry Husbandry.

GLENN W. HERRICK, B.S.A., Economic Entomology.

HOWARD W. RILEY, M.E., Farm Mechanics.

CYRUS R. CROSBY, A.B., Entomological Investigations.

HAROLD E. ROSS, M.S.A., Dairy Industry.

ELMER S. SAVAGE, M.S.A., Ph.D., Animal Husbandry.

LEWIS KNUDSON, B.S.A., Ph.D., Plant Physiology.

KENNETH C. LIVERMORE, B.S.in Agr., Farm Management.

ALVIN C. BEAL, Ph.D., Floriculture.

MORTIER F. BARRUS, A.B., Ph.D., Plant Pathology.

GEORGE W. TAILBY, JR., B.S.A., Superintendent of Live-stock.

EDWARD S. GUTHRIE, M.S. in Agr., Dairy Industry.

PAUL WORK, B.S., A.B. , Olericulture.

JOHN BENTLEY, JR., B.S., M.F., Forestry.

HARVEY L. AYRES, Dairy Industry.

EMMONS W. LELAND, B.S.A., Soil Technology.

CHARLES T. GREGORY, B.S. in Agr., Plant Pathology.

WALTER W. FISK, M.S.A., Dairy Industry.

R. D. ANTHONY, B.S., B.S. in Agr., Pomology. ,

The regular bulletins of the Station are sent free to persons residing in New
York State who request them.

490

CONTROL OF TWO ELM-TREE PESTS

GLENN W. HERRI CK
THE ELM LEAF-BEETLE

(Galerucella luteola Mull.)

The American elm is perhaps the greatest favorite among shade trees
in the United States. It is probably more widely planted for this purpose
than any other tree, especially in the eastern p^art of the country. Our
forefathers in New England, remembering their beloved English elms,
went into the woods, brought forth the slender, graceful young elms,
and set them in front of their homes and along their streets. As their
descendants marched westward they too remembered these fine trees
and followed the commendable example of their fathers. The fine trunk
of the elm, with its spreading branches terminating in graceful, pendulous
tips, makes it a very beautiful tree. There is no street more attractive
than an avenue almost arched with the mighty arms of the elms.

It is a source of great regret that the American elm is subject to the
attacks of a most injurious insect pest, the imported elm leaf-beetle.
But fortunately this pest can be controlled if fought with vigor and
thoroughness.

The imported elm leaf -beetle was abundant and injurious in Baltimore,
Maryland, in 1838. It must have come into the country about 1834.
Since that time it has gradually extended its territory until now it is
found as far north as Massachusetts and New York and as far west as
Ohio and Kentucky. In New York State it is destructive in the eastern
and central sections and will probably extend its activity gradually until
it covers the greater part of the State.

Professor Slingerland1 records the appearance of the beetle in Ithaca
for the first time in 1902. A student in Cornell University, P. B. Powell,
discovered the eggshells and the young and nearly mature grubs on July
13, 1902, on some elms along University Avenue, which leads to the Cornell
University campus. Apparently the infestation was light, for only a
few branches on a dozen trees were found affected. On July 16 beetles
were found, and on August 2 the beetles emerged from larvae collected
earlier. The beetles must soon have invaded the trees on the university
campus, and from that time until the spring of 1911 they steadily increased
in numbers and destructiveness. By 1911 the trees had begun to show
seriously the effects of the injury and a few had nearly succumbed. It

1 Entomological News, vol. 14, 1903, p. 30.

491

492

BULLETIN 333

is doubtful whether some of them will recover. Several English elms,
which are more subject to injury from this beetle than are American
elms, had to be cut down. A part of the injury to these trees, however,
was caused by the elm leaf -miner.

The condition of the trees in 1910 was such that it became imperative
to take preventive measures before another season should pass. Accord-

FIG. 164. — Spraying a high elm with a Hardie machine

ingly, the Board of Trustees of Cornell University made a liberal appro-
priation for spraying the elms on the university grounds, and preparation
for the work was at once begun. The problem seemed a rather large
one. However, the spraying has now been carried through two seasons,
and, while nothing startling has been developed in the way of new methods
or apparatus, the work has proved to be practical, economical, and efficient.

CONTROL OF Two ELM-TREE PESTS

493

SPRAYING APPARATUS

The first question which presented itself was that of the apparatus to
be used. It was necessary to procure machines that were not expensive.
Moreover, many of the trees were on steep hillsides and were difficult
to reach, so that the type of heavy machines used in work with the gipsy
moth did not seem suited to the present problem. Again, there were

FIG. 165. — Spraying a high elm with a Friend machine

comparatively few trees and it seemed unwise to spend a thousand dollars
or more for a very large machine. It was necessary, however, to have
a machine that would maintain a high pressure in order to force a stream
to the tops of the trees.

After a thorough consideration of all the points involved, it was decided
that two power spraying machines of the following specifications should

494 BULLETIN 333

be bought: (i) A Hardie Eastern Triplex power sprayer with 2oo-gallon
tank; a triplex pump with 2j-inch cylinders; a vertical 3 -horsepower
Ideal engine; two lines of |-inch hose, each 100 feet long; a 12 -foot tower;
two extension poles, one 20 feet and the other 12 feet long. (2) A Friend
Hilly-orchard Model power sprayer with 2oo-gallon tank; a large-size
California model pump; a 3j-horsepower engine; an 8-foot tower; and
other equipment the same as for the first-named machine. Each of these

FIG. 1 66. — Spraying from tower and from ground

machines was mounted on a truck ready for the field. The price of the
Hardie machine is $274 f. o. b. Hudson, Michigan; that of the heavy
Friend machine is $300 f. o. b. Gasport, New York. At all times it was
possible to maintain 200 pounds pressure with either outfit, and both
machines gave satisfactory results.

Bordeaux nozzles were used for all the work because these are adjust-
able. A solid stream could be thrown to the tops of the high trees, or
a fine spray could be used for the lower limbs.

CONTROL OF Two ELM-TREE PESTS

495

One man was stationed on the tower with the 20-foot extension rod.
When he desired to change from a solid stream to a mist spray he merely
lowered the nozzle to a man on the ground, who changed the adjustment
of the nozzle. The man on the ground sprayed the lower branches,
looked after the engine, and drove the team. An extra man was present,
the so-called foreman, who directed the work, mixed the solutions,
attended to breakdowns, climbed trees if necessary, and was generally
responsible for the spraying operations.

There is one rather serious fault to be found with the long extension
poles or with any of the common extension poles. The brass conducting
pipe on the pole is too small in diameter to carry enough liquid and,
besides, it greatly reduces the pressure at the nozzle. If a conducting
pipe of larger diameter could be made of a lighter material that would
stand the pressure, it would be advantageous. Much more liquid could
be thrown; the spraying could be done faster, and thus a larger amount
of space covered in a given time. Moreover, because of the pressure's
not being lessened, the stream could be thrown higher. For the short
poles, pieces of quarter-inch gas pipe 12 feet long were substituted in
the work here described and these gave better satisfaction. Longer
pieces of pipe than this, however, would be too heavy.

X j/ 'JjL, •- .»Jl r

liiftm

"'"I

Smaller spraying machines

Low and medium-sized trees may be sprayed with fair efficiency with
a hand-spraying outfit, such as is
shown in Fig. 167. This consists
of a barrel mounted on a two-wheeled
cart for convenience in moving from
tree to tree. A strong hand-pump is
fitted into the barrel. With such an
outfit a pressure of 75 pounds can
be maintained, although this requires
rather strenuous work on the part of
the man who does the pumping. In
connection with this barrel pump a
tall, firm step-ladder is needed, also
a piece of hose 50 feet long fitted to
an extension rod 10 or 12 feet long.
With an outfit of this kind, fairly
large and tall trees may be sprayed
efficiently and economically. FlG l6^_Hand.spraying outfit

496 BULLETIN 333

High-power spraying machines1

In the crusade in New England against the gipsy and brown-tail moths,
great improvements have been made in spraying outfits for forest and
shade trees. The machines have been made much heavier and the engines
are of high horsepower, so that solid streams are thrown to the tops of the
highest trees from a nozzle held by a man on the ground (Fig. 168). This
has greatly simplified the work of spraying forest and shade trees. Lines
of hose 200 or 300 feet in length are laid along the ground, leading from
the machine. In this manner trees on either side of the road, for a con-
siderable distance back from the fences, may be sprayed without the
machine's leaving the highway. Such machines cost about $1,000 and
are rather expensive for most of the work with shade trees. However,
they furnish almost an ideal method of spraying trees. With a high-
power machine of this type it is not necessary to have a tower or to climb
trees.

The large machines used in the work with gipsy moths have triplex
pumps and 8- or lo-horsepower engines. The two- and four-cycle engines
have been used, the latter apparently having given the better satisfaction.
Lately the two-cylinder marine-motor type of engine has been tried and
has proved very satisfactory. With these machines either ij-inch or
i -inch hose is used, the latter being preferable. The nozzle is of much
the same type as that used on fire hose.

SPRAYING OPERATIONS

In 1911 the first spraying was begun on May 16. This application
was made just as soon as the trees were in good leaf, although not in
full leaf. The adult, over-wintering beetles became active at least as
early as May 2. They had been observed on the windowpanes of houses
for some time previous to this date, therefore they must have left their
hibernating- places several days before. On May 1 1 the elms were rapidly
coming into leaf. The beetles were on the trees and were eating ravenously
on those trees that were well in leaf. The work was delayed, however,
until the following Monday, May 16, in order that more of the trees might
come into fuller leaf.

In 1912 the season was considerably later and spraying for the beetles
was not begun until June 13. The trees were well in leaf by May 27,
however, for on May 27 and 28 spraying for the elm leaf -miner was done.
There was a difference of about ten days between the two seasons. In
1912 the beetles were first noted on the trees on May 17. By May 2 1 they
were abundant and were eating ravenously.

Bulletin 87, Bureau of Entomology, United States Department of Agriculture, pp. 64-67.

CONTROL OF Two ELM-TREE PESTS

PHOTOGRAPH BY C. R. CROSBY

FIG. 1 68. — Spraying trees from the ground with
in Massachusetts

-power machines

PHOTOGRAPH BY C. R. CROSBY

FIG. 169. — Spraying trees with high-power machines in Massachusetts

498 BULLETIN 333

Paste arsenate of lead was used for the most part, at the rate of 3 pounds
to 50 gallons of water for the first application. For the second appli-
cation the proportion was 3! pounds to 50 gallons of water. On about
thirty-five trees powdered arsenate of lead was used, at the rate of ij
pounds to 50 gallons of water.

In all there were on the university grounds about five hundred and
thirty trees that were sprayed in 191 1. About one hundred of these
were scattered over the steep hillsides west of the buildings and along
University and Stewart avenues. Many of the trees were nearly a mile
from the campus water supply, and the majority were scattered and not
easy to reach. Exclusive of permanent equipment, the cost of spraying
these trees twice was $464.90, or an average of approximately 88 cents
each. The scattered trees raised materially the average cost of the whole.
If all the trees had stood along streets and reasonably near a water supply,
the average cost, the writer thinks, would have fallen below 70 cents. With
the two machines it took ten days to make the first spraying and eleven
days to make the second. The second spraying was done more thoroughly
and there was much more leaf surface to be covered; on the other hand,
experience had made the men more efficient. The great majority of
the trees were over forty years old, while some were older; nearly all
of them were large.

DETAILS OF COST OF SPRAYING ELMS ON CORNELL UNIVERSITY CAMPUS1

In order to give a clear idea of the cost of spraying elm trees, a few
details of the work on different days are here presented. The men were
paid $2 a day with the exception of the foreman, who was an experienced
man and who received $5 a day. The men who drove the teams and
sprayed the trees were inexperienced. The amount paid for teams was
$2 a day.

On June 20 the two machines sprayed eighty-two trees, some of which
were small. The total expense of this day, including men, teams, arsenate
of lead, and gasoline, was $24.91, an average of 30! cents per tree. On
June 1 6 sixty-six trees were sprayed at a total cost of $22.14, an average
°f 332 cents per tree; these were all large trees. On June 19 fifty-nine of
the largest trees on the campus were sprayed — those along Central
Avenue southward from the Library. The cost of spraying these trees
was $23.965, an average of 40! cents per tree. These trees stood close
to the street and near a water supply. They are very large trees,
having a great amount of leaf surface. This should give one a fair idea
as to the cost of spraying the largest trees.

1 Journal of Economic Entomology, vol. 5, no. 2, April, 1912, pp. 170-171.

CONTROL OF Two ELM-TREE PESTS

499

FIG. 170. — English elms kitted by leaf -beetles and -miners

FlG. 171. — English elms sprayed and recovering from attacks of beetles and miners

Soo BULLETIN 333

A careful and detailed record was kept of the actual cost of spraying
four hundred and thirty-five trees. Most of these trees were large and
all stood near the street and near the campus water supply. The cost
of spraying these trees once was $133.37, or 30.7 cents per tree. On the
average, each machine sprayed 36 J trees per day of eight hours, or 4!
trees per hour, or a single tree about every 13 J minutes. The average
quantity of liquid used for each tree was approximately i8| gallons.
With the bordeaux nozzle, or with any nozzle throwing a coarse stream,
considerable liquid is sure to be wasted. Nevertheless, the writer thinks
it is not wise to try to be too economical in the use of the spraying material.
Both the upper and undersides of the foliage should be covered, even
if some material goes to waste in getting about among the branches.

During the season of 1912 the beetles were not so abundant nor so
injurious. They appeared considerably later in the spring than in 1911.
No beetles were seen on the trees until May 1 7 and they were not abundant
until May 22. Spraying was begun on June 13 and finished on June 22.
This was a little later than usual, it having been decided to spray but once
because of the scarcity of beetles and because of the thorough spraying
in the preceding year. It cost $218.90 to spray the trees in 1912, an
average of 41 J cents per tree. Since only one application was given, the
work was done somewhat more thoroughly than before and considerably
more liquid was used. The men on the towers were paid $2.50 a day,
an advance of 50 cents over the amount paid in 1911.

Powdered ar senate of lead, at the rate of ij pounds to 50 gallons of
water, was used on one hundred and twenty-six trees. It gave as good
results in controlling the beetles as did the paste, and mixed a little more
readily with water. It was slightly more expensive than the paste.

COST OF SPRAYING SHADE TREES IN OTHER LOCALITIES

It has been shown that in the work at Cornell University the cost of
spraying each tree was about 30 to 41 cents when one application was given.
It is probably safe to say that the shade trees of most towns and cities
could be efficiently sprayed at this cost. It must be remembered that
the trees on the Cornell University campus were being sprayed by an
entomologist who was anxious that the work should be an unqualified
success, at least so far as controlling the beetle was concerned. Great
pains were taken to coat all parts of the trees, especially the topmost
and the inner branches. In order to do thorough, careful work, much
time and material must be consumed. Undoubtedly the trees were more
thoroughly sprayed than are average trees. It would be easy to cut the
cost of spraying one fourth or one third by slighting the work.

CONTROL OF Two ELM-TREE PESTS 501

The trees on Cornell Heights in the city of Ithaca, New York, were
sprayed in 1912 by contract at 22 \ cents each. These trees, which are
not very large, range from 20 to 30 feet in height. Individual trees in
the city of Ithaca are sprayed, by contract for the season, at a cost ranging
from $i to $2 per tree, depending on size, distance from water supply,
and other conditions. It often becomes necessary, in the case of these
individual trees, to use special care in order to prevent the spraying
material from being sprinkled on the houses. Moreover, many of the trees
in Ithaca are very large, and all such trees must be climbed in order to
reach the top.

Some figures showing the cost of spraying elm trees are given by Dr. E.
P. Felt.1 He reports Dr. J. B. Smith as saying that the elms on the
college campus at New Brunswick, New Jersey, were sprayed at odd
times by the janitors. It took two men, with a force-pump and ladders,
about one hour to spray a single tree. Including the poison used, the
cost was about 56 cents per tree. In the city of New Brunswick the
trees were sprayed at a contract price of $i, it being understood that
they were to receive three treatments if necessary.

Considerable data are given by Mr. Kirkland,2 of Massachusetts,
on the cost of spraying trees, mostly woodland trees. In general the
cost is 20 to 45 cents each for spraying trees averaging 35 to 60 feet in
height.

Doctor Felt states that the trees in Albany, which present a wide range
in size, were sprayed during the season of 1898 at the low cost of 15 cents
per tree. He reports later3 that the trees in Lansingburg, New York,
were sprayed at a cost price to the contractor of about 23 cents, while
in Troy the same contractor charged 50 to 60 cents for individual trees
here and there throughout the city.

In Albany the trees were sprayed in 1901 at an average cost of 22 cents
each when 5 pounds of Bowker's disparene to 100 gallons of water was
used. The average number of trees sprayed each day by each outfit
was forty.

The city of Saratoga Springs sprayed its maple trees in 1900 at an
average cost of iyj cents per tree. These trees were sprayed for the
forest tent-caterpillar, and the spraying did not require so much time
and material as would have been needed for the elm leaf -beetle.

PROPER TIME FOR SPRAYING

The first spraying should be done just as soon as the leaves are three
fourths grown or larger, and as soon as the characteristic feeding-holes

1 Bulletin 20, New York State Museum, 1898, p. 22.

3 Third Annual Report of Superintendent for Suppressing the Gipsy and Brown-tail Moths, 1908,
pp. 140-159.

3 Seventeenth Report New York State Entomologist, 1901, p. 739-

502

BULLETIN 333

of the beetles appear. The beetles come from their winter hibernating
places in early spring as the leaves are beginning to push out, and in a
few days they begin to eat holes in the leaves (Fig. 172). This is the time
when the first spraying should be done.

This time will vary with the earliness or lateness of the season. In
1911 the first spraying was begun on May 16, while in 1912 spraying was
not begun until June 13. This, however, was a few days later than
the work would have been begun had it been purposed to make two appli-
cations. In making the first application no particular attention need be

paid to coating the undersides of the leaves,
since the beetles eat holes entirely through the
foliage.

The second spraying should be done as the
eggs begin to hatch, which will be about three
weeks after the first application. In 1911 the
second spraying was begun nearly four weeks
after the first, but probably it should have
been begun somewhat earlier. In making this
application special pains should be taken to
coat the undersides of the leaves. The grubs of
the beetle work on the lower sides of the leaves
almost entirely, and in order to kill the insects
before they have done serious injury the poison
should be on the underside.

The first injury noticed by the grubs is likely
to be in the tops of the trees, although the
grubs have been seen seemingly as abundant
and injurious on the lower branches as higher
^ Nevertheless, the writer would emphasize
the importance of reaching the topmost branches
with the spray. If a few grubs are left in these branches they will
eventually transform and furnish a crop of adult beetles for succeeding
years.

The writer would also emphasize the necessity of spraying early for
beetles and for grubs. If the beetles or a large percentage of them are
killed, not many eggs will be deposited; while the grubs are much more
easily killed when young than when two thirds or three fourths grown.

AMOUNT OF POISON TO USE AND NUMBER OF TIMES TO SPRAY

As already stated, the trees were sprayed twice during the first season
of the work and the -mixture used was 3 pounds and 3^ pounds, respectively,
of paste arsenate of lead to 50 gallons of water. The brand of arsenate

FlG* I2'

""*"*

CONTROL OF Two ELM-TREE PESTS 503

of lead used contained about 15 per cent arsenic oxid. When powdered
arsenate of lead was used, the proportion was ij pound to 50 gallons
of water.

Other experimenters recommend the use of 4 pounds of paste arsenate
of lead to 50 gallons of water. A. F. Burgess, who has had much experi-
ence in combating the gipsy moth and the elm leaf -beetle, says that
" the cheapest and most satisfactory remedy for the gipsy moth and the
elm leaf-beetle consists in thoroughly spraying the trees with arsenate
of lead, using 10 pounds to 100 gallons of water, as early in the spring
as there is sufficient foliage to hold the poison." Mr. Burgess's aim is
to use a large amount of arsenate of lead and to spray but once. The
writer thinks this is a good practice to follow after one year of thorough
work. If the elms in a town or city have been neglected and allowed
to suffer for several seasons from the ravages of the beetle, the writer
thinks it would be desirable to give two sprayings the first season of
treatment, using in each application 3 to 3 J pounds of poison to 50 gallons
of water. Thereafter, probably one thorough spraying after the leaves
are fairly well out, using 4 to 5 pounds of arsenate of lead to 50 gal-
lons of water, would suffice. That practice has been followed and has
satisfactorily controlled the beetle.

To summarize, it would seem that 3 to 5 pounds of arsenate of lead to
50 gallons of water, with two applications the first year of the fight and
one thereafter, are sufficient.

LIFE HISTORY AND HABITS OF THE ELM LEAF-BEETLE

Appearance and work of the beetle

The insect is about one fourth of an inch long. In general it is yellow-
ish or brownish yellow in color, with a dark line along each side of its
back. Its color varies somewhat, and the over-wintering beetles are often
so dark-colored that the brownish yellow almost disappears and the dark
lines are hardly noticeable. In its normal coloring it is quite likely to
be confused with the common striped cucumber beetle, although it is
considerably larger.

When the beetle first awakens in the spring from its long winter sleep
it flies to the elm trees just bursting into leaf and takes its first meal by
eating small, irregular holes through the young, tender leaves (Fig. 172).

Story of its life

In the fall of the year many of the full-grown beetles, when searching
for snug crannies in which to pass the winter, find their way into dwelling-
houses, congregating especially in attics where they are often found by

504 BULLETIN 333

the score. Housekeepers are sometimes alarmed when they see so many
of these beetles crawling on their windowpanes, walls, and ceilings,
thinking that probably here is another household pest. Fortunately,
so far as the writer is aware, these insects do not injure household articles
of any description. Other individuals hide under loose pieces of bark
on trees, in cracks in fences and telegraph poles, in outhouses, sheds, and
any other sheltered places that they are able to find. Here they remain
in a quiet, inactive condition through the long winter months. With
the warm days of spring the beetles awake and begin crawling about
on the walks and on the windowpanes.

As soon as the leaves of the elm begin to appear the insects fly to the
trees for their first spring meal. After feeding for some time they deposit
their conspicuous orange-colored eggs (Fig. 173) in clusters of five to
twenty-five on the undersides of the leaves. The egg is flask-shaped, and
stands upright with its larger end attached to the leaf. The eggs hatch
in five or six days during hot weather, but in cool weather this period may
be prolonged several days. The grubs eat ravenously, increase rapidly
in size, and complete their growth in fifteen to twenty days. When full-
grown they either crawl down the trunk of the tree or drop from the
ends of the branches. At the bases of the trunks many of the larvag
transform into the yellow pupae (Fig. 176). Sometimes they are so
numerous that the pupae lie an inch deep about the foot of the tree.
Other larvae undergo transformation in crevices of the bark, espe-
cially if the trunk of the tree is rough; others go to gutters; while still
others seek shelter in crevices of the sidewalk and wherever they can
find hiding-places. The quiet, inactive pupae lie motionless for six to
ten days and then transform into adult beetles, thus completing the life
round of one generation.

Observations on the life cycle and number of generations at Ithaca

During the last week in April in 1911 the beetles became active and
were especially evident on the windowpanes of dwelling-houses. By
May 2 the elm trees were blooming and the leaf buds were beginning
to show green. By May n the trees were beginning to come into leaf
rapidly and some were fairly well in leaf. The beetles were present at
this time on the leaves and were eating ravenously. On May 16 eggs
were found on the leaves ; they were probably deposited a few days earlier.
On May 18 eggs were found in some abundance on the English elms.
On May 22 the first eggs were hatching; during the succeeding two
weeks the eggs were hatching in abundance. By June 18 a few larvae
were found pupating, and from that time into the first week in July

CONTROL OF Two ELM-TREE PESTS

505

FIG. 173. — Eggs, natural size, and much enlarged

FIG. 174. — Young grubs eating leaf

FIG. 176.— Pupa of the

elm leaf beetle

FIG. 175. — Grubs nearly grown

So6 BULLETIN 333

the larvae pupated in abundance. Several adult beetles were observed
emerging from scores of pupae at the bases of trees on July 8.

On July 17 many beetles were noted on the leaves of the elms, but no
eggs were found. On July 20, however, H. H. Knight discovered a bunch of
twelve eggs that had been deposited by a beetle found in the field on July 8.
This beetle had been confined in a cage in the insectary. On July 27
and July 30 Mr. Knight found an abundance of eggs of the second brood
on some English elms in the city of Ithaca. Some of these eggs were
already hatching, which showed that they had been deposited several
days earlier. By the first week in August the eggs of the second brood
were hatching in abundance. The English elms, on which the eggs were
found, had been practically defoliated by the first brood, not having
been sprayed; these trees had put forth a growth of new leaves. By
September i many larvae had left the trees and a few pupae were found
at the bases of the English elms. Most of the pupae of this second brood
were destroyed by the fungus Sporotrickum globuliferum. It is possible
that there is a partial third brood in Ithaca in favorable seasons, such
as that of 1911, for example. The history of the beetle was not followed
in detail further than the first week in September during that season,
but in the latter part of September the writer noted what were apparently
nearly full-grown larvae on elm leaves. These were possibly the larvae
of the third brood.

Doctor Felt1 has noted a partial third generation under favorable con-
ditions in the vicinity of Troy and Albany.

In 1912 the conditions were very different from those in 1911, for the
beetles appeared much later in the season. In fact, they appeared so
late that it was thought they were not coming in any abundance and
would do no great harm. They came late in the season, however, and
did considerable damage where no spraying was done.

In 1910 the writer stated, " Our observations show that in Ithaca
we have one generation, with a possible second, the latter, however,
being so small as to cause no serious damage."2 The observations on
which this statement was founded were made in 1910. The season of
1910 was similar to that of 1912, in which the beetles appeared late.
In 1910 and 1912 the second generation was apparently small and did
little damage, especially on the American elms where these observations
were made. This is a fair illustration of the absurdity of drawing general
conclusions and deducing general principles regarding the activities of
an insect, from observations carried on during only one season. More-
over, it would seem that these insects, at least in Ithaca, are much more

1 Bulletin 20, New York State Museum, 1898, p. 13.

8 Circular No. 8, Cornell University Agricultural Experiment Station. 1910, p. 4.

CONTROL OF Two ELM-TREE PESTS 507

abundant on English elms and that they pass through their life cycle
somewhat faster on these trees than on American elms. Therefore,
observations confined to individuals occurring on American elms might
lead to conclusions concerning the rapidity of development and num-
ber of broods different from those resulting if individuals occurring on
English elms were observed.

508 BULLETIN 333

THE ELM LEAF-MINER

(Kaliosyspkinga ulmi Sund.)

The Scotch and English elms and the Camperdown elms are subject
to the attacks of the larva of a small sawfly, which mines the tissues
of the leaves. Up to 1911 no adequate or effective method of control
of this miner had been found, so far as the writer is aware.

CONTROL MEASURES

Recalling the penetrating power of certain contact insecticides, it
occurred to the writer that possibly the larvae might be killed in their
mines in the leaves before they caused much injury. It was with a

rather forlorn hope, how-
ever, that a fine, small
Scotch elm, which had
been badly injured by
miners in previous years,
was sprayed in the spring
of 191 1.1

The material applied
consisted of " Black-leaf

40" tobacco extract,
FIG. 177-- The European dm sawfly, much enlarged ^^ ^ ^Q ^ Q£ ^

pint to 100 gallons of water, with 9 pounds of laundry soap dissolved
and added to the mixture. It was the intention to use but 8 pounds of
soap to 100 gallons of the mixture, but by mistake 9 pounds was added.
The application was made in May, 1911, just as the tiny mines had
begun to show in the leaves. The effect was certainly surprising. Many
of the sprayed leaves were examined during the succeeding few days and
every larva was found dead. Each one had evidently been killed at
once, the mines on the sprayed leaves not having been perceptibly
enlarged. The contrast later in the season between the topmost
branches, which could not be reached, and the lower branches was very
marked (Figs. 178 and 179). The leaves not sprayed were almost
completely mined and became withered and most unsightly.

In 1912 these experiments were repeated on a much larger scale, there
being several English elms on the university campus that had been badly
injured for several years. A row of such elms extends along a stone
wall bordering University Avenue. These trees were set by the founder
of the University, Ezra Cornell. They had suffered severely from attacks
of the leaf -beetle and the miner. Some of them had been so badly in-
jured that they had been cut out, while those remaining bore many

1 Journal of Economic Entomology, vol. 5, no. 2, April, 1912, p. 171.

CONTROL OF Two ELM-TREE PESTS

509

dead branches and were in a weak, dying condition,
sprayed thor-
oughly with
" Black-leaf"
tobacco ex-
tract, 3 gallons
to 200 gallons
of water, with
10 pounds of
fish-oil soap
and 8 pounds
of arsenate of
lead. "Black-
leaf " tobacco
extract con-
tains only 2.7
per cent nico-
tine and is
usually diluted
at the rate of

These trees were

FIG. 178. — Unsprayed leaves infested with the miner
i gallon to 70 or 80 gallons of water.

In these experiments the mixture
was slightly
stronger than this,
because of the
necessity of
thorough work.

Owing to diffi-
culty with the pump
and the engine
there was a delay
of a day or two in
getting to these
trees, and some of
the larger larvae
were not killed so
soon as had been
expected. The
tobacco must have
worked o n them
FIG. 1 79.— Sprayed leaves from the same tree slowly, however,

for the trees made
better growth than they had before in some years, and looked in the fall

510 BULLETIN 333

as though they had taken a new hold on life (Fig. 171). A row of the
same kind of trees of about the same age, not far from these, nearly all
died during the summer and were cut down (Fig. 170). It is evident
that the "Black-leaf" extract does not work so fast as does the
"Black-leaf 40."

Eight other trees were sprayed on May 28 with " Black-leaf 40 " (which
contains 40 per cent nicotine), at the rate of i pint to 100 gallons of water,
with 5 pounds of fish-oil soap and 3 pounds of powdered arsenate of lead
added. These trees, which had been badly injured by the miner in pre-
ceding seasons, were in good condition at the end of this season. All the
young miners and many of the older ones were killed at once in their
mines. Here and there, where the leaves had not been thoroughly coated
with the mixture, some of the larvae that were larger and older at the
time of spraying escaped.

One Camperdown elm was sprayed thoroughly. It was low and the
leaves could be coated thoroughly on both sides. The miners were com-
pletely held in check on this tree.

On the whole, the work showed that this pest of the European elms
can be held in check if taken at the proper time. The trees must be
sprayed early, just as soon as the tiny mines begin to show in the leaves.

The " Black-leaf 40," i pint to 100 gallons of water with 5 pounds
of soap, seems to be more effective than the " Black-leaf." One great
advantage of these tobacco extracts is that the arsenate of lead may be
added for the leaf -beetle, thus obviating the necessity of a separate spray-
ing for each insect.

It might be well to say that " Black-leaf 40 " is a tobacco extract
manufactured by the Kentucky Tobacco Product Company, Louisville,"
Kentucky. It may be bought from that firm direct, or it may be pro-
cured from several distributing agents in the State. It is sold by the
Leadley Drug Company, Batavia, the Rex Company, Rochester, and the
Parsons Drug Company, Albion. The price is $12.50 per gallon or
$1.85 per pint. When it is diluted at the rate of i pint to 100 gallons
of water, however, it costs no more than lime-sulfur or other contact
insecticides.

LIFE HISTORY OF THE ELM LEAF-MINER

The adult insect is a small, shining black sawfly about one eighth of
an inch in length. The wings expand about one third of an inch. In
the latter part of May the sawflies may be seen on the leaves of the elm.
They are not shy and can often be picked up with the fingers.

The tiny, milk-white eggs are thrust by the female into the tissues
of the leaf from the upper side. They hatch in about one week and the

CONTROL OF Two ELM-TREE PESTS

young larvae begin their mines at once. The majority of the eggs are
probably deposited, in most seasons, in the middle of May.

The larvae grow rapidly, and by July i all have practically completed
their growth and gone into the ground under the tree. Here they burrow
downward an inch or less and soon make a thin, brown, papery cocoon
in which they hibernate until the next May. Apparently they pass the
winter as larvae, changing into pupae in the spring. Thus there is but
one brood a vear.

C

FIG. 1 80. — Larvae, of elm leaf -miner, much
enlarged

FIG. 181. — Three eggs of elm leaf-
miner stuck in leaf. Much
enlarged

NATURE OF INJURIES CAUSED BY THE ELM LEAF-MINER

The work of this miner becomes very conspicuous in June. The leaves
become blotched and blistered by the mines of the larvae. Several miners
usually attack a single leaf and their mines eventually coalesce and form
large, whitish blisters (Fig. 178). Often the inner tissues of nearly the
whole leaf are mined out, forming a blister over the entire area of the
leaf. The leaves then wither and turn brown and the tree looks as though
it had been scorched by fire. Unless the leaves are wholly mined they
remain on the tree. Small trees are often almost defoliated, especially
small Camperdown elms. A half dozen small English elms standing in
a group on the campus have been most seriously injured for several
seasons.

512 BULLETIN 333

JUDICIOUS PLANTING AS AN AID IN THE CONTROL OF

THESE PESTS

In view of the wide and serious injury to shade trees by many different
insects, it becomes pertinent to discuss some general principles of control
of such pests. In the first place, it is unwise to depend almost entirely
on one species of tree for shade or ornament. The very existence of
the American elm, for example, in the eastern United States at least,
is threatened by two serious pests, the elm leaf -beetle and the leopard
moth. Probably the elm leaf -beetle could be controlled if every owner
of elm trees would spray. It is quite probable that the leopard moth
cannot be controlled and that eventually the elms will succumb to these
two pests. The trees have already disappeared from the Harvard Yard
as a result of the ravages of these insects. The sugar maples are becoming
more and more subject to serious injuries from borers. Many fine trees
are dying each year and there seems to be no help for the situation.
The graceful white birches are going one by one as a result of the ravages
of the bronze birch borer, while the hickories are hard beset by the hickory
bark-borer.

With these facts in mind, it is important to give careful and thoughtful
consideration of the question of the wise selection and planting of shade
trees. A city in which the streets are planted only to elms and maples is
likely to be without shade trees in the near future. The wide planting
of one kind of tree over considerable territory forms ideal conditions
for the increase and spread of an extended outbreak of an injurious
species of insect. On the other hand, if adjacent streets are planted to
different varieties of shade trees an outbreak of any single pest can be
checked and controlled much more easily. Elms and maples can well
be supplanted in many cases by oaks, especially the pin oak and the red
oak, or by the ginkgo tree — a handsome but rather slow-growing tree,
and one remarkably free from pests. The Norway maples make fine
shade trees, and so do the linden, the horse-chestnut, and the American
ash.

JANUARY, 1906

BULLETIN 234

CORNELL UNIVERSITY

AGRICULTURAL EXPERIMENT STATION OF
THE COLLEGE OF AGRICULTURE

Department of Entomology

THE BRONZE BIRCHBORER:

AN INSECT DESTROYING THE WHITE BIRCH

An infested birch in one of the Buffalo Parks,

By M. V. SLINGERLAND

ITHACA, N. Y.
PUBLISHED BY THE UNIVERSITY.

ORGANIZATION

OF THE CORNELL UNIVERSITY AGRICULTURAL EXPERIMENT

STATION.

BOARD OF CONTROL

THE TRUSTEES OF THE UNIVERSITY.

THE AGRICULTURAL COLLEGE AND STATION COUNCIL

JACOB GOULD SCHURMAN, President of the University.

FRANKLIN C. CORNELL, Trustee of the University.

LIBERTY H. BAILEY, Director of the Agricultural College and Experiment Station.

EMMONS L. WILLIAMS, Treasurer of the University.

JOHN H. COMSTOCK, Professor of Entomology.

THOMAS F. HUNT, Professor of Agronomy.

EXPERIMENTING STAFF

\ . LIBERTY H. BAILEY, Director.

JOHN HENRY COMSTOCK, Entomology.

HENRY H. WING, Animal Husbandry.

GEORGE F. ATKINSON, Botany.

JOHN CRAIG, Horticulture.

THOMAS F. HUNT, Agronomy.

RAYMOND A. PEARSON, Dairy Industry.

MARK V. SLINGERLAND, Entomology.

GEORGE W. CAVANAUGH, Chemistry.
I JOHN L. STONE, Agronomy.

JAMES E. RICE, Poultry Husbandry.

JOHN W. GILMORE, Agronomy.

HERBERT H. WHETZEL, Plant Pathology.

SAMUEL FRASER, Agronomy.

JAMES A. BIZZELL, Chemistry.

ELMER O. FIPPIN, Soil Investigation.

CHARLES E. HUNN, Horticulture.

Office of the Director, 17 Morrill Hall.

The regular bulletins of the Station are sent free to persons residing in New York
State who request them.

THE BRONZE BIRCH BORER

Agrilus anxius Gory
Order COLEOPTERA ; family BUPRESTID^E

The birch trees with their graceful habits, their slender, often pendulous
branches, and their picturesque trunks are conspicuous features of any land-
scape. The European white birch in its various weeping and cut-leaved forms
has been extensively planted in American city parks and private lawns. Its
artistic beauty, with its silvery stemmed branches and fluttering leaves
"floating at the discretion of the winds " makes the white birch a constant
source of delight both in summer and winter. As compared with the elm or
maple, the white birch is considered a short-lived, tree, but they frequently
survive to grace a landscape for thirty years or more.

It is with much regret, therefore, that this Experiment Station finds it

necessary through this bulletin to
announce to lovers of these beauti-
ful white birches that a deadly
insect enemy has recently appeared
which is fast destroying these trees
in city parks and on home grounds.
Hundreds of the finest specimens
of these graceful trees in Buffalo,
(see frontispiece) Ithaca and other
cities and towns of New York have
succumbed to this enemy within the
past eight years. About half of the
score of white birches on the Cor-
nell University Campus (Fig. 34),
some of them over thirty years old,
have been killed by the insect with-
in three years ; and several of the
remaining trees are infested and
will not survive more than a year
or two. These facts demonstrate
the seriousness of the situation, and
demand that city authorities and
private owners of these valuable
trees acquaint themselves with the
, Characteristic rusty brown spots on details of the work and life-habits

this it SO that remedial meas-

FIG. 30

bark over the borer in antumn, naturals:
birch branch showing the peculiar ridged effect over

the burrow of borer, reduced in size.

ures may be promptly and judici-
ously applied.

66 BULLETIN 234

INDICATIONS OF THE INSECT'S PRESENCE

The presence of this insect in birch trees is not easily determined until it
has been at work for a year or more. The first intimation one usually has of
its presence is the dying of some of the top branches of the tree. This is well
shown in the frontispiece and in Fig. 34. This dying of the tops of the trees
has been very characteristic of the work of this pest wherever I have seen it
in New York. The whole tree often Succumbs in another year or two.
Rarely the trees might begin to die at the top from a condition known as
"stag head" caused by lack of moisture and food materials. A careful
examination should readily locate the borer if it is the culprit. Some have
tried to save a tree by pruning out the dead branches or top, but without avail
for by that time the whole tree usually is infested.

Sometimes one can determine in autumn whether a tree is infested by this
insect, even before any branches have been killed. Characteristic reddish or
rusty brown spots or discolorations, as shown at a in Fig. 30, often occur on
the white bark of the trunk and larger branches at the point where the insect
is preparing to hibernate and transform in the wood beneath. Usually the
insect can be easily located by cutting through the bark and into the wood
beneath these rather conspicuous spots.

Another peculiarity which characterizes the work of the insect is the ridge
which often develops in the bark over the burrow on the branches, as shown
at b in Fig. 30.

Thus, while the insect works in rather an obscure manner, it indicates
its presence in the above described characteristic and sometimes conspicuous
ways. Unfortunately, however, it is usually then too late to save the tree, but
much can be done to prevent further infestation of other trees.

CHARACTERISTICS OF THE ENEMY

This destroyer of white birches is a small, slender, olive-bronze colored
beetle nearly half an inch in length (7.5-11.5 m m.), as shown in Figs. 31
and 35. * Its general color and the fact that it works mostly in birch trees
suggested the good popular name of Bronze Birch Borer for the insect. How-
ever, it is not in this adult or beetle stage that the insect is destructive. It
is injurious only during its life as a larva or grub when it is a borer.

*Chittenden (Bull. 18, U. S. Div. of Entomology, p. 47) technically describes it as
•« of moderately robust form, subopaque, olivaceous bronze in color. The last ventral
segment is oval at the apex ; the punctuation of the prothorax is transversely strigoso—
punctate, and its posterior angles are carinate in both sexes ; the first ventral segment in
the male is broadly grooved ; the second more deeply, the groove being narrow and smooth
(see t in Fig. 31). The serration of the antennal joints begins with the fourth joint. The
elytra bear each a rather vague longitudinal costa and the scutellum is transversely
carinate". The popular name of the insect was first suggested in this account by
Chittenden.

THE BRONZE BIRCH BORER

FlG. 31. — The Bronze

Borer, a, female beetle ; b, first
abdominal segments of male from
below ; c, grub or borer. All
enlarged about three and one-
half times. (From Bull. 18, U. S.
Bureau of Entomology).

The borer (Figs. 31 and 35), is a slender,
flattened, footless, creamy white grub about three
fourths of an inch long when fully grown. Its
small head with dark brown mouth-parts is
retracted into the wide, flattened first thoracic
segment giving it a flat-headed appearance. The
other segments of the body are not so wide, the
second and third thoracic being the narrowest.
The caudal end of the body ends in two brown,
horny, forceps-like processes with bidentate
inner margins. It is this slender creature which
is responsible for the killing of the trees. It
may be found in autumn by cutting into the trees
beneath the rusty-colored spots described on page
66 as occuring on the bark (Fig. 30 a}. These
grubs make tortuous or zigzag burrows in the sap-
wood around and across the trunk and branches
of infested trees, as shown in Figs. 360, and 32 m

a quarter of a century old.

WORK OF THE INSECT

This borer attacks white birches of all sizes
from nursery trees to stately monarchs more than
All parts of the tree, from branches a quarter of
an inch in diameter to the main trunk, mav be infested The top branches
are always first attacked and killed, then the infestation spreads into the other
branches and trunk.
The tiny borer,
hatching from an egg
laid by the adult or
beetle on the bark,
begins a narrow mine
or burrow through
the bark. The bur-
row is extended in a
tortuous or zigzag
direction along the
branch, getting wider
as the borer grows,
and running mostly
in the sap-wood just
beneath the bark, but
sometimes going for a

short distance deeper into Ihe wood, even to the centre of the branch.
borer packs the burrow behind it with its excrement and wood particles which

FlG. 32. — The burrow nj a single borer as it zigzagged around
and through this 2-foot branch for a distance of over 5 feet.
Much reduced

The

68

BULLETIN 234

turn dark brown in the first or smaller portion of the mine. The flattened
grub makes a shallow burrow that gradually widens to an eighth of an inch.
Many of these zigzag, packed burrows are shown at a in Fig. 36.

It is difficult to follow a burrow throughout its whole length. Larsen
(Mich. Acad, Sci., 3rd. Kept. 1902, p. 48) states that he followed one
"through its winding course a distance of i foot and 7 inches in a length
of branch of 4 inches, now near the bark, now deep down in the wood ; now
running upwards in the branch, now running downwards. Neither the
beginning nor the end of this burrow was found. The branch was somewhat

FlG. 33. — Portion of trunk of infested white birch, showing no injury apparent until the
tark is removed and the numerous burrows of the borer revealed. Natural size.

less than an inch in diameter. Another burrow was traced upwards in a
branch of about half an inch in diameter a distance of about 18 inches, then
doubling upon itself ran downwards parallel to the upward course ". I
followed the burrow shown in Fig. 32, from (he point where the grub had
formed its hibernating and transforming cell in the wood back to the starting
point on a branch about an inch in diameter and two feet long. The course
of the burrow is shown in the figure, but one can get from the picture but a
faint notion of the numerous turnings and zigzriggings of the burrow as it
extended along and around the branch. Eight times the borer tunneled its
way through the wood to the centre of the branch or farther, once working
along for about four inches near the centre-. This burrow, the work of a single
borer, measured a little over five feet in length, and it was evidently all made
between June ist and Oct. ist. Surely this is a remarkable piece of work

FIG 34. — On the Cornell University Campus. The white birch tree in the fate-
ground was killed l>\> the bronze birch borer and the other birch tree acros*
the road shows the characteristic work (top branches dying) of the insect.

FIG. 3^. — <?, The bronze birch borer beetle, natural size in lower coi ner : />, t lie grub
or borer, natural size above.

FIG. 36. — a, Portion of trunk of white birch with bark removed to shoio how tlie burrows of
the borer sometimes zigzag across eacJi oilier ; b, shows a burrow extending through the
wnod : r, hibernating and transforming chambers in tlie wood a short distance beneath the

bark. All figures reduced slightly.

THE BRONZE BIRCH BORER yt

and must have kept the little creature chewing nearly every moment of the
four months.

Oftentimes on the trunk and larger branches the burrows of several
borers zigzag across each other in interminable confusion, as shown at a in Fig.
36. Yet it is a remarkable fact that even in this case where the infestation
was very severe, there were no indications on the bark of the trunk of any
injury beneath, or that the tree was infested by a borer ; this fact is well shown
in Fig. 33, where small portions of the bark were removed and the numerous
burrows of the borer revealed. The burrows mostly extend through the grow-
ing wood just beneath the bark, and often the effort of the tree to repair the
injury results in a woody growth over the burrow that causes corresponding
ridges to appear on the bark (Fig. 30, £). Sometimes a burrow can be
traced for several inches by these ridges on the bark. The next year's
growth of the tree may cover an old burrow with wood, and burrows have been
found thus buried under three annual rings of woody growth, showing that the
tree might overcome some of the injury were it not for renewed attacks by the
pest. Sometimes the burrowing of the borers weakens the limbs to such an
extent that they break from their own weight.

HISTORICAL NOTES

Scientific name. — The first record in the literature of this Bronze Birch Borer concerned
its scientific name. Like many other American insect pests, this borer was also named in
Europe. One of the adults or beetles found its way into the collection of Dejean, a
Frenchman, who published lists of the beetles he had. In the third edition of his Catalogue
des Coleopteres (p. 63) issued in 1836, he listed this birch borer, giving it the name of
Agrilus anxius. But the honor of naming the insect is now credited to Gory, another
Frenchman, who first published in 1841 a description of it and courteously used Dejean's
name (Hist. Nat. des Coleopteres, Monog. des Buprestides, Vol. 4, p. 226). Dejean
recorded the insect from Boreal America.

In 1859, the insect was first recorded in American literature by Le Conte, and was then
described under two different names as Agrilus gr avis, from Lake Superior and New York,
and Agrilus torpidus from Lake Superior and Illinois (Trans. Am. Phil. Soc., XI, p, 247) ;
he recorded Agrilus anxius from Massachusetts. The former names fell as synonyms of
Gory's earlier name of anxius when Dr. Horn monographed the genus Agrilus in 1891,
(Trans. Am. Ent. Soc. XVIII, p. 277-366.

Early economic records. — Dr. Lintner was the first to record anything about the habits
of the insect. In 1883, he collected 62 of the beetles "which were observed alighting
from their flight in the bright sunshine, and running actively in jerking motions, over the
bark upon some cut poplars piled by the wayside" in the Adirondack Region of New York.
He suggested that the larva was probably a borer in poplar (37th. An. Kept. N. Y. State
Mus. Nat. Hist. p. 50.; the same account occurs in Lintner's fth Kept. p. 281). In 1884,
Harrington took specimens of the beetles on willows in Quebec (Can. Ent. Vol. XVI, p.
101), and in 1889, Blanchard recorded it as occurring on the foliage of poplar sprouts in
Massachusetts, and he took a few specimens on the summit of Mt. Washington, N. Hamp.,
•• whither they had flown from below " (Ent. Am. Vol. V, p. 32).

The first notice of this borer attacking birch «appears to be that of Schwarz who men-
tioned the insect in 1890, in connection with the work of a Scolytid beetle, Xyloterus poli-
tus (Proc. Ent. Soc., Wash., Vol. II, p. 78) at Detriot, Mich., where two silver birche*
were killed. The same year Cook (3rd An. Kept. Mich. Expt. Sta., p.i 19), bred the insect

72 BULLETIN 234

from galls which were quite common in Michigan on a willow (Salix discolor}. Davis
describes these galls (Insect Life, IV, p. 66) as an oval swelling of the live branch in
which the borer tunnels "an oval gallery downward from the gall, sometimes in the pith,
but oftener indiscriminately through the wood, and makes its exit often an inch and a half
below." This work in willow is so different from that of Agrilus auxins in birch, that I
was inclined to doubt the identity of the two borers, but an examination of one of Cook's
specimens convinced me that they are probably the same insect, and Mr. E. A. Schwarz
confirms this. As the specimen was a female, it was impossible to determine it definitely.

In 1896, Jack reported (Garden and Forest for 1896, p. 269), that " some of the foreign
birches in the Arboretum and other localities about Boston have been killed by the attacks
of boring larvae " which were doubtless this Bronze Birch Borer. About the same time
the white birches in the parks of Buffalo began to die from the attacks of this pest, and
during the past six years the insect has killed hundreds of these beautiful trees in Buffalo,
Rochester, Hornellsville, Ithaca and doubtless other cities in New York ; and similar
destructive work is reported from Detroit and Ann Arbor in Michigan, from Chicago, and
from Guelph, London and Hamilton in Canada. It is still continuing its ravages in some
of these cities, slowly spreading from tree to tree, as practically no well directed effort is
being made to check it.

A good summary of previous records of the insect and an account of its work in Buffalo
was given by Chittenden in 1898 and 1900 (Bull. No 18, new series, U. S. Div. of Entomology,
p. 44-51, and Bull. 22 of the same Division, p. 64-65). In apaper on " A Disease of the
White Birch" read in March, 1901, before the Michigan Academy of Science (3rd Rept. of
Mich. Acad. Sci. 1902, p. 46-49) John Larsen gave an excellent account of many original
observations on the work and habits of this insect. Professor Lochhead well summarized
the records in 1903, (28th An. Rept. Ontario Agr. Coll. & Exp. Farm for 1902, p. 22-23).

THE DISTRIBUTION AND DESTRUCTIVENESS OF THE INSECT

This bronze birch borer is an American insect and is widely distributed
throughout the northern United States and Canada. It has been recorded
from New Hampshire and Massachusetts westward through Connecticut, New
Jersey, New York, Pennsylvania, Virginia, Quebec and Ontario in Canada,
Michigan and Illinois to Colorado. Thus far it has been reported as injurious
only in Massachusetts, New York, Michigan, Illinois and Ontario in Canada.
But doubtless many white birches in other States have been killed by the
insect, the real cause being unknown or unrecorded.

In New York state this borer now occurs in destructive numbers in St.
Lawrence County, and in the following cities : Buffalo, Rochester, Ithaca,
Hornellsville, and probably others. The beetles have been taken in other
parts of the State, and it is liable to appear in destructive numbers wherever
white birches are used as ornamental trees.

In Europe two similar borers (Agrilus betuleti Ratz. and Agrilus viridis
L.) are destructive to birches.

The fact that the bronze birch borer often kills large trees in three or
four years is sufficient evidence of its very destructive character. Within a
few years many white birches in Chicago, Ann Arbor, Detroit, Buffalo, Ithaca
and other cities have been killed by the insect. A tree usually succumbs
within two or three years after the first top branches die.

In 1895, M. F. Adams, a keen observer of ins°ct life, discovered that

"1'HE BRONZE BIRCH BORER 73

the common white birches in Buffalo's parks were injuriously infested by a
borer. By 1898, several trees had been killed, the cut-leaved varieties
also were being attacked, and the culprit was found to be the bronze
birch borer. I saw in Delaware Avenue Park in Buffalo on May n. i8gg, at
least one hundred magnificent white birches, some of them veritable monarchs
nearly two feet in diameter at the base, all dying from the work of this borer.
In August of the same year, Mr. Adams reported that from one spot in one
of Buffalo's parks he could see fourteen black and yellow birches, but twelve
of them were dead, all killed by this borer. Chamberlain reported in 1900,
(Scientific American, Vol, 82, p. 42), that the result of the work of this insect
is that " nine-tenths of Buffalo's white birches are either dead or dying and the
rest will soon follow. Several hundred have died, including about 50 in Forest
Lawn Cemetery the present season. Even the dead trees were not burned,
and the pests were allowed to multiply at will."

I have seen over half of the white birches on the Cornell University
Campus and many of those scattered about Ithaca's lawns killed by the insect
within the past three or four years. And unless the vigorous, prompt, and
judicious measures now being enforced on the Campus are carried out through-
out the city, Ithaca's white birches will soon be dead monuments to the
industry and destrucliveness of this little enemy.

FOOD- PLANTS OR KINDS OF TREES ATTACKED

This insect seems to confine its work almost entirely to birch trees. The
only exception yet recorded is discussed on page 72 where it was found mak-
ing gall-like swellings on a willow. The European white birch (Bttula alba)
and its cut-leaved weeping variety (pendu/a laciniata} have suffered most
from its ravages. In the outbreak in Buffalo, the former or alba was first
attacked, the infestation then extending to the cut-leaved variety. But I have
seen a case in Ithaca, where a cut-leaved birch was killed before a tree of the
whole-leaved form only a rod or two distant showed any signs of being infested.

Several trees of the American black (J3etu!a lento} and the yellow (Betula
luted) birch have been killed by the insect in Buffalo, and it is also recorded
as attacking the paper or canoe birch (Betula papyriferd] .

However, there is no record of any kinds of birches having been killed
by the insect in forests or woodlands. It seems to have confined its destruct-
ive work to the more valuable individuals and groups of these beautiful trees
set in parks and private lawns.

The beetles have been taken on poplars cut and piled by the roadside,
on poplar sprouts and trunks, and on willow, but there is no evidence that the
insect was breeding in poplar. Larsen put a number of the beetles in a cage
and supplied them with fresh leaves. " When only birch leaves were supplied
they fed very sparingly. Some elm leaves were then put in with the birch and
they fed greedily upon these. This led to further experiment and various
sorts of lea?ves were used. They fed upon almost any leaf of soft texture.
But their favorite food was willow, poplar and aspen leaves with preference

74

JU/LLF/riN 23.}.

strongly marked in the order given. It seems from this that the beetles upon
leaving the birch feed on other trees until he time for reproduction."

THE LIFE AND HABITS OF THE INSECT

The chain of evidence regarding the life-story of this bronze birch borer
is not yet quite complete, but from the records and from my observations and
investigations most of the details can be supplied.

Hibernation. — All the evidence I have, shows that the insect always passes
the winter as a full-grown grub or borer curled up in a long, narrow cell or
chamber, which it makes in the wood not far from the bark. I have failed to
find smaller borers in uncompleted burrows in autumn. One of these hiber-
nating cells is shown at c in Fig. 36. Most of the borers may be found in these
cells early in October; Adams reports finding some as early as July i4th.
Some of them can be easily located by cutting into the tree beneath the char-
acteristic rusty colored spots (Fig. 30, #). The grubs rest in the cells in a
peculiar manner with the cephalic third of the body bent around lying close to
the remainder. They are very sluggish when removed from the cells. Early
in the spring these hibernated borers shorten up, straighten out in their cells,
and thus prepare for transforming.

Transformation and habits in spring. — During the latter part of April or
early in May, depending upon weather conditions, the grubs transform in their
hibernating cells into the adult insects or beetles (Figs. 31 and 35). A day or
two before transforming the pupae turn to the dark bronzy color of the beetle.

In making its hibernating and transforming chamber in the wood in early
autumn, the borer also extends its burrow up to the bark, so that in the spring
the newly-transformed beetles only have to squeeze their way out of the cell
and eat their way through the bark. Larsen records that the emergence of
the beetles is rather a laborious process, as some were found "with the for-
ward parts of their bodies protruding for hours making long rests between
efforts to free themselves." Several of the peculiar shaped exit holes of the
beetles are shown in Fig. 37.
Eleven exit holes have been
counted in an area only two
and a half inches in diameter.

The date of emergence
of the beetles in the spring is
of much importance in con-
nection with methods for
controlling it, and it varies
somewhat with climatic and
other conditions. Sometimes
a few of them emnge as early
as May ist, but my observa-
tions and breeding notes in
New York, indicate that most

of them do not appear i mil

Fit;. 37.- A.i// hoies oj the bronze bitch borer beetles
the bark. Natural size.

THE BRONZE BIRCH BORER 7-

from May i5th to June ist, or even later. In 1900 Adams reported that none
of the beetles had emerged by June 3rd. The beetles feed on tender foliage, evi-
dently preferring other trees like the willow and poplars, as Larsen has shown.

Egg-laying. — I have not seen the eggs of this bronze birch borer as I
could not induce the beetles to lay eggs in my cages, but Larsen was more
fortunate and obtained evidence that they were laid in crevices of the bark.
He states that beetles ''confined in a glass jar were found to be depositing
eggs on June 8th, and for a week or more afterwards. Pieces of fresh limbs
were supplied, but the insects did not deposit their eggs upon these, but moved
about feeling for crevices with their long prehensile ovipositor and having
found a place, such as between the glass and the lower part of the cork or
under a piece of wood, from five to ten or more eggs were put in one place.
Copulation had gone on for sometime before this. Great activity was exhib-
ited during the copulation and egg-laying. No observations were made on the
development of the eggs. " It is unfortunate that the eggs were not described.

As further evidence that the eggs are laid several in a place in crevices or
rough places on the bark, is the fact that the burrow I followed from end to
end, as described on page 68 and shown in Fig. 32, began at a rough place
where a twig had been broken off. And Larsen found that " in one place in
a slight swelling on the bark were several small openings, less in diameter than
a pin. From these openings burrows were traced. The burrows are at first
very small and lie close under the^bark and are filled with dark granules."
Adams wrote me of a similar observation made in Buffalo early in June, 1899.
He " detected the beginnings of the burrows by a slight circular discoloration
on the outer bark."

Thus the evidence indicates that after feeding for a few days, the beetles
mate and the eggs are laid early in June in rough places on the bark of the
birches, first on the upper branches and later on the trunk.

Work of the borer. — The beginning of the newly-hatched borer's burrow-
ings in the bark in June have just been described in the preceding paragraph.
And its later work as it industriously tunnels its way, zigzagging around and
through the branches has been described on page 68. Beginning early in
June, the borer must work almost incessantly to be able to dig such a tunnel
in less than four months, or before October ist.

Length of the life-cycle. — Although no one has followed this birch pest
through its whole life, all the recorded evidence and all my observations indi-
cate a yearly life-cycle.* I have just made a careful examination of much of
the infested portion of a large white birch, and I found nothing but full-grown
grubs or borers and exit holes of last year's generation. There were no indi-

* Most of the species of Agrilut* both European and American, whose life-history has
been fully worked out, require two years to complete a life-cycle or generation. This is
true of Agrilus viridis and Agrilus sinuatus, both European species, the latter now an
American pest also. But our native Agrilus bilineatus and Agrilus ruficollis seem to have
a yearly life-cycle.

y6 BULLETIN 234

cations of small or half -grown borers, as there would be if the insect required
two seasons to develop.

NATURAL ENEMIES

Were it not for the ubiquitous English sparrow, doubtless the woodpeck-
ers would help considerably in reducing the numbers of this bronze birch
borer. The sparrows have largely driven the woodpeckers out of city parks
and private grounds. During most of its life, or for about eleven months
in a year, the borer is just under the bark where the birds could easily get at
it. Adams observed one of the common woodpeckers, probably the hairy
woodpecker, feeding quite extensively upon the grubs in Buffalo.

The pest does not escape from parasitic enemies. While examining
some infested branches of birch in January, 1899, I found several borers that
had been killed by parasitic grubs. The parasite had spun a tough, semi-
transparent cocoon inside the skin of its host. Later the adult parasite was
bred and it proved to be the interesting little creature shown much enlarged in

FIG. 38. — Phasgonophora sulcata. The interesting 1. 1 lie parasitic
enemy of the btonze birch borer. Much enlatged.

Fig. 38. It is a Chalcid fly known to science as Phasgonophora sulcata West-
wood (Griffith's Animal Kingdom, Insects, Vol. II, p. 432). Note the won-
derful development of the hind legs, the purpose of which is unknown. Chit-
tenden also reared the same parasite from this borer and from the flat-headed
apple-borer infesting a Japanese redbud tree. The parasites issued about
two weeks after the beetles. Dr. Howard writes me that the parasite has
been taken in Texas, California, Washington, D. C., Illinois, South Caro-
lina, Canada, Florida and Oregon, thus showing a very wide distribution.
Doubtless this interesting little enemy aids materially in holding this bronze
birch borer in check. But in most localities it has not yet reached that point
where it is numerous enough to cope with the pest to the extent that man
need not employ artificial agencies to prevent the destruction of his beautiful
white birches.

THE BRONZE BIRCH BORER 77

REMEDIAL SUGGESTIONS

This bronze birch borer is practically invulnerable against man's usual
insecticides. Nearly all of its life is spent as a borer under the bark out of
reach of insecticides. The fact that the beetles feed for a few days on tender
leaves would suggest spraying the trees in May with a poison, but apparently
they do not eat the birch foliage to any extent, preferring that of willow, pop-
lar, or elm. Thus it is very doubtful if it would materially check the insect
to spray the birches with a poison.

On account of the possibility that the beetles might be prevented from
emerging or from laying their eggs, several applications to the bark have been
suggested, such as a poisoned whitewash, a mixture of hydraulic cement and
skim milk, covering the trunks with a paper wrapping, and a resin-oil wash.
Adams treated about forty trees in Buffalo with a resin-oil wash (5 pounds
resin dissolved and i gallon raw linseed oil poured in) with no satisfactory
results. As the insect infests all parts of the tree, from branches half an
inch in diameter to the trunk, it would be difficult to so cover the bark
as to allow no place for egg-laying, or to put on such a coating as to prevent the
exit of the beetles. I doubt the practicability and effectiveness of such
methods against this birch borer.

Some have tried to save their trees by cutting out the top branches that
were dead or dying, but in every case the trees finally succumbed. This
pruning may sometimes delay the inevitable death of the tree for a year or
more. / doubt if a tree can be saved after it is once infested to the extent that
the top branches are dying. Better sacrifice the whole tree at once and thus
prevent the spread of the pest to neighboring trees.

This brings me to the only practicable and effective method of dealing
with this borer. That is the heroic one of cutting down and burning the
infested tree, trunk and branches, before May ist, thus destroying the whole
crop or generation of borers in their hibernating quarters under the bark.
As soon as the top branches are killed (as shown in the frontispiece and in
Fig- 34)) do not delay a moment, but cut and burn the tree, as its death is
inevitable within a year or two.

But this is much more easily said than done, as any one can testify who
has tried to persuade owners of private grounds or park authorities to apply
the method in time. Sentiment and the forlorn hope that the tree may revive
or last a few years more, often results in an infested tree remaining as a leaf-
less eyesore on the landscape for a year or more after it is dead and all the
beetles have been allowed to emerge and spread to other trees. It seems to
be almost impossible in many cases to get individuals or city authorities to act
promptly. Often after one succeeds in getting an infested tree cut down in
time, it will not be burned promptly, but left where the beetles can readily
emerge, so that practically nothing is accomplished in checking the pest.

A determined effort is' now being made to save the remaining white

78 BULLETIN 234

birches on the University Campus. This autumn all the infested trees show-
ing dying tops are being removed and promptly burned. In cities and towns
where this insect is killing the white birches, there should be enacted an ordin-
ance compelling the authorities to promptly cut and burn in autumn, winter,
and surely before May ist, the infested trees in the parks, and if possible
requiring owners of private grounds to do the same. The mere enactment of
such an ordinance will not often accomplish the desire'cyresult. Public opinion
must be behind such a measure to enforce it. Ithaca Buffalo, Rochester and
other New York State cities are now face to face with the problem of check-
ing this pest or of losing their white birches. Civic Improvement Societies
could render efficient aid in such work.

Briefly then , there is no known way of preventing this bronze birch borer
from attacking white birches, and the only practicable and effective method yet
found for checking its ravages is to promptly cut and burn the- infested trees in
autumn, in winter, or before May ist. There is no possibility of saving a tree
when the top branches are dead, as shown in the frontispiece and in Fig. jj>.
Cut and burn such trees at once and thus prevent the spread of the insect.

NOVEMBER, 1912

BULLETIN 322

CORNELL UNIVERSITY

AGRICULTURAL EXPERIMENT STATION OF

THE COLLEGE OF AGRICULTURE

Department of Entomology

THE LARCH CASE-BEARER

BY GLENN W. HERRICK

L
J

D

LJ

h
J

ITHACA, N. Y.
PUBLISHED BY THE UNIVERSITY

CORNELL UNIVERSITY
AGRICULTURAL EXPERIMENT STATION

EXPERIMENTING STAFF

LIBERTY H. BAILEY, M.S., LL.D., Director.

ALBERT R. MANN, B.S.A., Secretary and Editor.

JOHN H. COMSTOCK, B.S., Entomology.

HENRY H. WING, M.S. in Agr., Animal Husbandry.

T. LYTTLETON LYON, Ph.D., Soil Technology.

HERBERT J. WEBBER, M.A., Ph.D., Plant-Breeding.

JOHN L. STONE, B. Agr., Farm Practice and Farm Crops.

JAMES E. RICE, B.S.A., Poultry Husbandry.

GEORGE W. CAVANAUGH, B.S., Chemistry.

HERBERT H. WHETZEL, A.B., M.A., Plant Pathology.

ELMER O. PIPPIN, B.S.A., Soil Technology.

GEORGE F. WARREN, Ph.D., Farm Management.

WILLIAM A. STOCKING, JR., M.S.A., Dairy Industry.

CHARLES S. WILSON, A.B.,M.S.A., Pomology.

WILFORD M. WILSON, M.D., Meteorology.

WALTER MULFORD, B.S.A., F.E., Forestry.

HARRY H. LOVE, Ph.D., Plant-Breeding Investigations.

ARTHUR W. GILBERT, Ph.D., Plant-Breeding.

DONALD REDDICK, A.B., Ph.D., Plant Pathology.

EDWARD G. MONTGOMERY, M.A., Farm Crops.

WILLIAM A. RILEY, Ph.D., Entomology.

MERRITT W. HARPER, M.S., Animal Husbandry.

J. A. BIZZELL, Ph.D., Soil Technology.

CLARENCE A. ROGERS, M.S.A., Poultry Husbandry.

GLENN W. HERRICK, B.S.A., Economic Entomology.

HOWARD W. RILEY, M.E., Farm Mechanics.

CYRUS R. CROSBY, A.B., Entomological Investigations.

HAROLD E. ROSS, M.S.A., Dairy Industry.

ELMER S. SAVAGE, M.S.A., Ph.D., Animal Husbandry.

LEWIS KNUDSON, B.S.A., Ph.D., Plant Physiology.

KENNETH C. LIVERMORE, B.S.inAgr., Farm Management.

ALVIN C. BEAL, Ph.D., Floriculture.

MORTIER F. BARRUS, A.B., Plant Pathology.

GEORGE W. TAILBY, JR., B.S.A., Superintendent of Live Stock.

EDWARD S. GUTHRIE, M.S. in Agr., Dairy Industry.

PAUL WORK, B.S., A.B., Olericulture.

EDWARD R. MINNS, B.S A., Farm Practice and Farm Crops.

JOHN BENTLEY, JR., B.S., M.F., Forestry.

HARVEY L. AYRES, Superintendent of Dairy Manufacture j.

EMMONS W. LELAND, B.S.A., Soil Technology.

CHARLES T. GREGORY, B.S. in Agr., Plant Pathology.

WALTER W. FISK, B.S. in Agr., Dairy Industry.

R. D. ANTHONY, B.S., B.S. in Agr., Pomology.

The regular bulletins of the Station are sent free to persons residing in New
York State who request them.

THE LARCH CASE-BEARER

(Coleophora laricella Hbn.)
Order, Lepidoptera Family, Elachistidae

GLENN W. HERRI CK

Many of our favorite ornamental trees are subject to the attacks of
various pests, which in some cases, notably on the elms, white birches,
and hickories, prove very serious. In fact, there is scarcely a shade
tree that has not one or more enemies with which to contend. The larch,
which is widely used as an ornamental tree and is much admired for its
soft, green, feathery foliage, has struggled for years with the larch saw-
fly and with the larch case-bearer. Although these two pests were first
discovered in this country at about the same time, yet the case-bearer
has not attracted much attention until within the last ten years. For
several seasons the larches used for ornamental purposes on the campus
of Cornell University have been rather seriously injured by the small
larvae of this case-bearer. Opportunity has thus been offered to observe
the habits, injuries, and life history of this interesting insect during the
past two years. The writer was fortunate in finding an apparently
satisfactory method of controlling this pest on trees used for ornamental
purposes, but the method would not be practicable for trees in a forest.

HISTORY OF THE LARCH CASE-BEARER, AND INJURIES CAUSED BY THE INSECT

The larch case-bearer is a European insect and has been known in
Europe for many years, it having been originally described in 1827 by
the German worker, Hiibner. In Europe, especially in Germany, it is a
serious pest to the forest larches and the Germans have given it con-
siderable attention. The insect found its way to England and Scotland
when the larch was introduced into Great Britain. Later it reached
America.

Doctor Hagen was the first person to definitely record the presence
of the insect in this country. He found it on twigs sent to him from the
private grounds of Henry Watson in Northampton, Mass., in 1886. It
was found on specimens of the European larch (Larix europed) that had
been planted along an avenue. These trees were thirty years old and had
never been affected before, so far as had been noted. The pest had evi-
dently not been introduced with the trees, but had come in later from

NOTE. — D. E. Fink, student assistant, gave valuable aid by his observations in the field during the
summer of 1910.

39

40 BULLETIN 322

some other source. J. G. Jack, writing in Garden and Forest in 1896,
says that the insect had been known in the Arnold Arboretum at Cam-
bridge, Mass., for many years. It is quite possible that this case-bearer
reached America earlier than 1886. It has evidently spread slowly in
this country.

In 1905 Dr. James Fletcher recorded the insect at Ottawa, Canada,
where it was working on the European larches. He says that " the num-
bers of the larvae upon the trees at Ottawa in May last were not large
enough to have any serious effects upon either the growth or appearance
of the trees; but I regret to find this autumn that the small cases of the
larvae are enormously more abundant than they were last spring."

Dr. C. Gordon Hewitt writes under date of March 29, 1912, that this
species infests both the native tamarack and the European larch in eastern
Canada, and that during the past two years it has been exceedingly abun-
dant in certain localities, especially in the provinces of New Brunswick
and Nova Scotia. He says, " The most serious depredations of this
insect which I have witnessed were in Nova Scotia where considerable
areas of tamarack had been attacked; the destruction and shrivelling up
of the foliage gave the trees a characteristic light-brown color, quite
distinct at a distance from the appearance produced by the defoliations
by the larch sawfly, Lygaeonematus erichsonii"

Doctor Fletcher quotes an account of Rudolph Japing, Forest Assessor,
Muenden, Hanover, Germany, concerning this pest, in which the latter
says, " The injury to the trees from these insects can be very great, espe-
cially in the spring. The growth stops and the trees become feeble and
are thus susceptible to canker, which often follows the damage done by
the insect. The larch case-bearer is mostly found on trees from ten to
forty years old."

Cecconi says that he has observed the invasion to begin generally
at the topmost part of the trees and to extend gradually toward
the base. Young trees and the most vigorous ones are preferred, while
the old trees and those isolated are generally spared. He calls attention
to the great numbers of the larvae in the larch forests of Bellino, Italy,
in 1904. He says that from nearly eight hundred grams of dry branches
(that is, withered) sent to him in May and taken from the breeding cage
about the end of August, he obtained more than six thousand moths.

The insect is also becoming a pest of considerable importance in the
forests of the northeastern United States. Miss Patch observed the case-
bearers over a period of two years in Maine. She found them rather
widely distributed on larches in the forest, and committing serious injury.
She says, " Although minute, they have been present in such enormous
numbers that larch trees have often been, during the past three seasons,

THE LARCH CASE-BEARER 41

eaten bare of green early in the spring. . . . Small larches in the
vicinity of Bangor and Orono which have been subjected to an attack
of at least three seasons died this summer from no other apparent cause
than the presence of great numbers of the case-bearers which kept the
needles eaten off. Many large larches infested by this insect look yellowish
and unhealthy."

The case-bearer has been present on larches in the vicinity of Ithaca
for several years and undoubtedly has done considerable injury. The
small green leaves are devoured in early spring as fast as they push out,
and on many trees the green tissues are eaten out and the leaves left
pale and bleached in early spring (Figs. 14 and 15). Badly infested
trees show the effects of the work of this insect and fail to make their
normal growth. Many of the branches are killed outright.

The records of this department show that complaints of injury have
been received from Franklin county, New York. The author has also
found the case-bearer in abundance on larches in the Adirondacks in the
vicinity of Cranberry Lake. The work of the insect was apparent on
the trees, but was almost overshadowed by the much more serious
injuries of the larch sawfly (Lygaeonematus erichsonii).

Doctor Felt records the case-bearer in the vicinity of Albany, N. Y.,
where he has seen it at work for several years on ornamental larches.

THE NAME

The larch case-bearer belongs to that large group of moths commonly
known as the Tineids. These moths are all small and have narrow wings
fringed with very long, slender scales. Although small, some of them are
really very beautiful, surpassing many of our larger moths in brilliancy
and richness of coloring. Since this species of insect infests only the larch,
and since the larva always lives in a case, it has very properly been given
the name " larch case-bearer." Its scientific name, Coleophora laricella,
is also very appropriate. The word " Coleophora " means bearing a
sheath, and the word " laricella " refers to the larch — the ending " ella "
meaning small. Hence, we have a small case-bearer living on the larch.

The following is the history of its scientific names: In 1827 Hiibner,
a German worker, named the insect Tinea laricella and figured the moth
and the larva. Seven years later, Treitschke, another German ento-
mologist, put the insect in his genus Ornix, and added the termination
pennella to the specific name or gyro because he thought all species belonging
to this genus should end with pennella. Four years after, Duponchel put
the insect in the genus Gracillaria, and in 1839 Zeller placed it in the genus
Coleophora and retained Hiibner 's specific name laricella. Under the
last name it still remains.

42 BULLETIN 322

Synonymy of Coleophora laricella

1827 Tinea laricella Hbn., Samm. Europ. Schmett., V, fig. 427.

1834 Ornix argyropennella Treit., Schmetterl. Europa, X, part III, p. 221.

1838 Gracillaria laricella Du., Histoire Naturelle des Lepidopteres, etc., XI, p. 586,

pi. 311, fig. 3.

1839 Coleophora laricella Zell., Isis, p. 208.

1840 Tinea laricella Ratz., Forst-Insecten, part II, p. 244

DISTRIBUTION AND FOOD PLANTS

The larch case-bearer is a European insect and is rather widely dis-
tributed over Europe, being especially abundant and injurious in Germany.
It has been reported as injurious in Italy, France, Switzerland, and Fin-
land. It very probably exists in other countries on the Continent. It
is also widely distributed in Great Britain, probably having been intro-
duced on the European larch, the larch not being indigenous to the British
Isles.

As has been stated, the case-bearer probably reached this country by
being introduced on the European larch. It is now certainly widely dis-
tributed in the northeastern United States — New York and New England.
Doctor Felt records it as present on larches in the vicinity of Albany,
N. Y., and Doctor Fletcher recorded it in the vicinity of Ottawa, Canada,
in 1905.

The food plants of the insect evidently consist of the European and
American larches. The latter tree is known in the United States as the
tamarack, or hackmatack, and sometimes, although erroneously, the
juniper.

It is said that the Japanese larches are not attacked by this case-bearer.
Cecconi records it as attacking the Larix leptolepis in Italy.

LIFE HISTORY

The larch case-bearer has an interesting life history and most interesting
habits. It passes a very protected life, for while young it lives in burrows
within the larch leaves and later it fashions a case in which it ensconces
itself and which it never leaves as a larva. Undoubtedly this case serves
to protect the tiny larva from extreme weather conditions, if not from
insect enemies.

Hibernation

By a strange instinct the larva? migrate in the autumn from the
deciduous leaves of the larch upon which they have been feeding, and
securely fasten themselves in their tiny cases to the branches. Here
instinct tells them they will be safe from falling to the ground and will
be accessible to their food supply in the early spring.

THE LARCH CASE-BEARER

43

When the larvae enter hibernation in the fall they are very small and
only about one fourth to one third grown. Their cases at this time are
long and slender, for each case is merely a piece of a mined leaf from the
larch. The cases are nearly cylindrical, for, although the leaves of the
larch are flat, the body of the larva evidently fills out the hollow leaf
and makes it cylindrical. The outer, or free, end of the case is usually
slightly contracted and fully closed with a sheet of silk. The other end
of the case is securely attached to the branch with a copious supply of
silk. Some of the cases lie flat along the branch, while others project at
various angles as shown in Figs. 5 and 1 2 . Very often the cases occur in

FIG. 5. — Hibernating case-bearers, natural size

bunches of four or five clustered in the axil of a bud. The winter cases
vary considerably in length, measuring all the way from one eighth to
one sixth of an inch.

In the fall of 1910 the majority of the larvae did not migrate from the
leaves to the branches until the latter part of October. On October 24
most of them were still actively feeding on the leaves, but a few had moved
down to the branches. By October 31 the great majority had established
themselves in their winter quarters. Here they remained until the fol-
lowing April, nearly six months, in a perfectly quiescent condition.

The case-bearers in spring

As soon as the buds of the larch begin to put out in the spring, the case-
bearers wake from their long winter's sleep and migrate to the buds (Fig. 1 1) .

44 BULLETIN 322

In the spring of 1910 the larvae had begun migrating to the buds by April
15, but in 1911 they were about ten days later owing to the retarded
opening of the buds. Before leaving its place on the branch the larva
sheds its skin. The cast skins, with the dark-colored skeletons of the
head, can be found among the tangled silk on the twigs where the case-
bearers were fastened during the winter.

The young larva attacks a leaf in an interesting manner. It eats a
tiny hole through the epidermis of the leaf and mines out the inside tissues
of the leaf as far on each side of the entrance opening as it can reach.
During this time it does not let go its hold of the case, but remains attached
to it by its posterior prolegs and wriggles back into it when disturbed.
Attacked leaves soon assume a bleached, whitened appearance (Fig. 10),
and when deserted by the larva they shrivel and curl.

One larva must attack a great number of the small young leaves, for
in cases observed in 1910 the larva? were not abundant enough to do the
damage that they did unless each case-bearer attacked and injured several
leaves. As bearing on this point, a branch six inches long was selected
and it was found that this branch bore 24 whorls of leaves; one whorl,
at this particular stage, containing 54 small leaves and other nascent ones
in the center that could not be counted. If 54 leaves be taken as the
average, then the branch bore 1,296 leaves that were of a size to be attrac-
tive to the larvae. On this branch were ten case-bearers. These larvae
had evidently begun at the bottom of the branch, for they were now near
the tip, and every leaf of any size had been injured except those in the last
whorl. Moreover, the larvae had injured the outside leaves first because
these were largest, and now they were going down into the middle of the
buds to get at the small growing green leaves in the center. These ten
larvae had probably eaten and injured over a thousand leaves.

About the first thing that a case-bearer does after it reaches the fresh
buds in the spring is to enlarge its old winter case. This it does by slitting
the case lengthwise on the underside and then inserting a gore of silk.
The buds are not far enough out at this time so that the larva can obtain
leaves for enlarging its case. In the spring of 1912 the case-bearers first
began migrating to the buds on April 2 1 , a warm, sunny day. They lived
on the growing buds for nearly ten days before they were able to find
leaves long enough to cut off and fasten to their cases over the slit already
made and filled with silk. In addition to this enlargement in diameter
of the case, it is also now increased in length by the addition of silk to the
anterior end. The new leaf is usually cut longer than the old case, so
that on the underside of the case the leaf extends the whole length
(Fig. 9). At this period in the life of the larva it destroys many leaves,
for it passes from one to another as has been already pointed out. Cecconi

THE LARCH CASE-BEARER

45

FIG. 6. — The female moth, much enlarged

FIG. 7.. — Eggs on larch leaves,
enlarged

FIG. 8. — Young larva in cases just formed in autumn.
Enlarged

46

BULLETIN 322

FIG. 9. — Full-grown larva in case, much enlarged

FIG. 10. — Work
of larva on leaf

FIG. 1 1 . — Over -wintering larva getting their first meal in the spring.
Enlarged

THE LARCH CASE-BEARER

47

FIG. 12. — Hibernating case-bearers on branches in winter. Enlarged

FIG, 13. — Full-grown larva in position for pupation.
Enlarged

BULLETIN 322

/

FIG. 14. — Badly injured branches at right and left, with
normal branch between

FIG. 15. — Badly injured buds at left, normal buds at right

THE LARCH CASE-BEARER 49

says that when the larvae have consumed all the needles on one branchlet
they lower themselves down to others by means of a silken thread. He
also noted that they devoured the flowers of the larch.

Apparently the larva lives in this enlarged case during the remaining
time of its growth and pupates within it.

The larva

The larva is dark reddish brown and, when full-grown, about one fifth
of an inch in length (4^ to 5 mm.). The head is black, and the thoracic
shield is black but divided along the middle. The last segment of the
abdomen bears a black plate on the dorsal side. The anterior pairs of
prolegs are small and each one is furnished with a circle of minute hooks;
while each of the posterior prolegs bears a half circle of strong hooks point-
ing forward, by which the larva clings most tenaciously to its case. The
end of the caudal segment of the abdomen is beset with strong chitinized
setae pointing straight caudad.

The favorite locations for the larvae to attach themselves when ready
to pupate seem to be at the bases of the short side branches and in the
center of the leaf whorls. In Fig. 13 is shown a cluster of four pupae
at the base of a short side branch. The pupal stage lasts fourteen to
twenty days. The pupa is small and brownish black, with no char-
acteristic markings.

The moth

The moths were appearing by May 24 in 1911 and were abundant from
that time on. The moth is small, silvery grayish brown in color, with
no conspicuous markings. Both pairs of wings are narrow, especially
the hind wings, and fringed with long, slender scales (Fig. 6). The wings
expand about one third of an inch. The moths are active during the
daytime and when at rest they alight on the stems or leaves, with the
wings closely folded along the body and the antennae projecting straight
forward.

Within a few days the moths pair, and in a week to ten days from
emergence begin laying their eggs.

The egg

The eggs are small, but plainly visible to the unaided eye, and in shape
they resemble an inverted teacup. Each egg is conspicuously marked
with twelve to fourteen ridges radiating down the sides from the apex.
The eggs are conspicuous objects on the green leaves of the larch, being
cinnamon-rufous in color and standing out clearly in contrast to the green.
They seem to be laid indiscriminately on the upper and under sides of

50 BULLETIN 322

the leaves (Fig. 7). The great majority of the eggs, in the vicinity
of Ithaca, are deposited during the first part of June. In 1910 an
abundance of eggs was found in the field on June 10. The time will
vary somewhat, however, in different years.

The summer habits of the larva

When the larva hatches from the egg it bores directly through the floor,
or bottom side, of the eggshell, and thence through the epidermis of the
leaf into the inside. Mr. Fink demonstrated this habit of the larva very
clearly, for he found specimens in the act of entering the leaf in this manner.
Mr. Fink and the writer were puzzled by not finding any openings in the
leaves_ through which the larvae had entered, until they found individuals
entering directly from the egg. The larva, being exceedingly small,
mines very slowly at first; but after a few weeks the light-colored mine,
with the dark body of the miner showing through, is seen. The light-
colored eggshell clings to the leaf for many days, but if it is tipped over
one may find the opening through the epidermis to the mine.

The larvae live within the leaves of the larch, gradually enlarging their
mines until September. The leaves as they are mined appear russet ed.
As the tiny miner grows and enlarges its burrow, it packs the empty part
of the mine with excrement. During 1910 the miners began to emerge
from their burrows in the larch leaves and to make their winter cases
during the first half of September. Sometimes these cases were made of
the old leaves in which the larvae had lived all summer, but often they
were made of newly mined leaves. When the larva gets ready to form
its winter case it cuts off the end of the leaf in which it has lived all summer.
The larva then cleans out the burrow, goes to the lower end of the mine
next to the base of the leaf, and cuts off enough of the mined leaf to make
its case. The mine of the larva is large enough to allow its occupant to
turn around with ease and whenever occasion demands. The larva is
very neat in its habits, for it backs up from time to time in its work, pro-
trudes the posterior end of the body, and ejects the excrement outside.
Occasionally one finds a case still bearing the eggshell of an egg laid nearly
three months previously. The inside of the case is lined with a very thin,
delicate layer of silk.

Some of the larvae, as already noted, make cases out of new leaves.
After the middle of September one often finds naked larvae wandering
over the leaves of the larch. These are the ones that have left their old
mines and have gone in search of new leaves to excavate for their winter
cases. When a suitable leaf is found the larva mines it out and makes
the case in the same way as described above.

THE LARCH CASE-BEARER 51

After making their winter cases the larvae feed for three or four weeks
before entering hibernation. They migrate from the leaves in normal
seasons during the latter part of October.

The larvae during this period of their lives may attack more than one
leaf. One would infer from Ratzeburg that as soon as the larva emerges
in September from its summer mine it builds its winter case and goes
into hibernation without more injury. Cecconi points out that in Italy
the larva feeds on the leaves before going into hibernation, and may mine
quite thoroughly more than one leaf after having made its winter case.
There is undoubtedly considerable injury done by the larvae at this period
of their lives. The leaves of the larch are, however, so large and so abun-
dant that this injury does not become conspicuous as a usual thing.

Number of broods

As the life history just detailed indicates, there is but one brood in a
year. This is similar to the life history of the cigar case-bearer and of
the pistol case-bearer on apples.

NATURAL ENEMIES

The larch case-bearer is subject to the attacks of a number of parasites,
especially in Europe. Two or three parasites have been bred at this
station, but not in large numbers. As yet, not enough material has been
obtained for determination. J. C. Crawford very kindly examined the
few that were obtained here, but could place them only provisionally
until he had more specimens for examination. He says, " One is a species
of Pteromalidae, apparently belonging to the tribe Pteromalini ;' the second
is a species of the genus Pachyneuron ; the third is a Tetrastichine and prob-
ably of the genus Tetrastichus."

The following parasites are recorded as having been bred from this
insect in Europe; Bracon guttiger Wesm., Microdus pumilus Ratz., Campo-
plex nanus Gr., Anaphes(?), Entedon arcuatus Frst., Entedon laricinellae
Ratz., Pteromalus laricinellae Ratz., Campoplex tumidulus Gr., and Campo-
plex virginalis Gr.

METHODS OF CONTROL

No practicable method of control is known for this case-bearer on forest
trees over large areas. It can be controlled, however, on trees used for
ornamental purposes. An account is given below of experiments at this
station with arsenate of lead and the lime-sulfur solution. The concen-
trated lime-sulfur solution, diluted at winter strengths, proved very effec-
tive in killing the case-bearers while in hibernation.

52 BULLETIN 322

Ar senate of lead

From success obtained with arsenate of lead in controlling the closely
allied cigar case-bearer and pistol case-bearer on apples, it has been sug-
gested that the larch case-bearer could be controlled by the same method.
It must be remembered, however, that the pistol case-bearer, at least,
eats much larger quantities of the foliage. That is, it is not so exclusively
a miner as is the larch case-bearer. Moreover, the cigar case-bearer,
in its mining and making of new cases, seems to devour more actual leaf
surface and thus, presumably, obtain more poison than would be the case
with the larch case-bearer. In order to test this method, however, five
larch trees well infested with the case-bearers were sprayed with arsenate
of lead at the rate of 2^ pounds to 50 gallons of water. These trees were
thoroughly sprayed on April 25. The buds were just starting to grow
well and the case-bearers were just coming on them from their winter
quarters.

The trees were examined from time to time, but no appreciable diminu-
tion in the numbers of case-bearers could be noted.

On May 5 the trees, with one exception, were carefully and thoroughly
sprayed again. At this time the leaves were of fair size and the case-
bearers were abundant.

The trees were observed throughout the season, but no difference in
the amount of injury could be seen between these and many others
untreated.

In looking over the trees shortly after they were sprayed, the poison
was found to be invariably gathered in small globules at the bases of the
leaves. The leaves of the larch are small, narrow, and glossy. The poison
does not seem to stick to the narrow needles and consequently does not
become well distributed over the surface of the leaves. It is possible that
a small quantity of soap added to the mixture would enable the poison
to spread and stick better.

Laboratory experiments with arsenate of lead gave very inconclusive
results.

In the light of experiments at this station, the writer would not feel
justified in recommending the use of arsenate of lead for control of the
larch case-bearer.

Lime-sulfur

From experience gained in controlling the bud moth on pecans and the
ribbed cocoon-maker on apples by spraying the trees in the dormant
season with lime-sulfur, thus killing the hibernating larvae and pupae,
it seemed possible to do the same with the larch case-bearer. Accord-
ingly, on April 7, 1911, before the buds had begun to swell and before
the larvae had left their winter positions, a badly infested tree was sprayed

THE LARCH CASE-BEARER 53

with lime-sulfur at scale strengths. The lime-sulfur was the homemade
concentrated, and tested 29° Beaume. It was diluted i to 7 and the tree
thoroughly coated from top to bottom. The next day there was a heavy
fall of snow. The subsequent three or four days were clear and sunny.

On April 2 7 an examination of the trees showed that the buds had started
and that on the unsprayed trees the larvae had moved to the leaves.
On the sprayed tree, however, not a larva had left its winter position.
On May 5 the writer examined many larvae and found only two alive.
The others were dried up and dead. In subsequent examinations the
writer was unable to find that a single larva had moved from its hiber-
nating position to the leaves.

Lime-sulfur is evidently a simple and effective remedy for the larch
case-bearer. Probably the best results will be obtained by applying the
mixture to the trees just as late as possible in the spring before the buds
start growing. There is evidently no injury to buds or tender wood at
this time if the mixture is used at scale strengths, say i gallon to 8| gallons
of water when the concentrated solution tests 33° Beauine*. The mixture
should be applied thoroughly to all the branches, and the tree should be
completely covered with the solution.

BIBLIOGRAPHY OF THE LARCH CASE-BEARER

1827. Hubner, Jakob. — Sammlung Europaischer Schmetterlinge, V, fig.

427.
1834. Treitschke, Friedrich. — Die Schmetterlinge von Europa, X, part

III, p. 221.

1838. Duponchel. — Histoire Naturelle des Lepidopteres, etc., XI, p. 586,

pi. 311, fig. 3.

1839. Zeller, P. C — Isis, p. 208.

1840. Ratzeburg, T. C. — For st -Insect en, part II, p. 244.
1849. Zeller, P. C. — Linnaea Entomologica, vol. 4, p. 376.

1853. Herrich-Schaeffer. — Systematische Bearbeitung der Schmetter-
linge von Europa, etc., vol. 5, p. 230, fig. 667.

1856. Frey, Heinrich. — Die Tineen und Pterophoren, p. 218.

1859. Stainton, H. J. — Natural History of the Tineina, vol. IV, p. 68.

1880. Taschenburg, Dr. E. L. — Praktische Insekten-Kunde, part III, p.
289.

1882. Snellen, P. C. T. — De Vlinders van Nederland, part II, p. 806.

1886. Hagen, H. A. — Canadian Entomologist, vol. 18, p: 125.

1892. Jack, J. G. — Garden and Forest, February 24, p. 87.

1892. Riley and Howard. — Insect Life, vol. 4, p. 405.

1895. Judeich und Nitsche. — Lehrbuch der Mitteleuropaischen Forstin-
sektenkunde, vol. II, p. 1041.

54 BULLETIN 322

1895. Meyrick, Edward. — A Handbook of British Lepidoptera, p. 649.
1895. Schlich, Dr. W. — Manual of Forestry, vol. IV, p. 311.

1901. Staudinger und Rebel. — Catalog der Lepidopteren des Palaearc-

tischen Faunengebietes, part II, p. 190.

1902. Dyar, H. G. — List of North American Lepidoptera, p. 532.
1904. Cecconi, Dr. Giacomo. — Bullettino della Societa Entomologica

Italiana, vol. 36, p. 103.

1904. Theobald, F. V. — Gardeners' Chronicle, third series, no. 924,

pp. 181-182.

1905. Fletcher, Dr. J. — 36th Ann. Rept. Ent. Soc. Ont., p. 90.

1905. Fletcher, Dr. J. — Rept. Ent. and Bot., Canada Dept. Agr., p. 191.

1906. Patch, E. M. — Bui. 134, Maine Exp. Sta., p. 218.

1906. Turner, H. J. — Notes on Coleophora solitariella, C. pyrrhulipennella,
C. laricella, etc. The Entomologist's Record, vol. 18, p. 118.

1908. Gillanders, A. T. — Forest Entomology, p. 281.

1909. Smith, J. B. — The Insects of New Jersey, p. 564.

1910. Tragardh, Ivar. — Larktradsmalen (Coleophora laricella Hbn.).

Entomologisk Tidskrift, p. 258.

1911. Herrick, G. W.— Ann. Ent. Soc. Amer., vol. IV, p. 68.

CORNELL UNIVERSITY AGRICULTURAL
EXPERIMENT STATION

THE FOLLOWING BULLETINS AND CIRCULARS ARE AVAILABLE FOR DISTRIBUTION TO
THOSE RESIDENTS OF NEW YORK STATE WHO MAY DESIRE THEM

219 Diseases of ginseng

262 Apple orchard survey of Niagara county

265 On certain seed-infesting chalcis-flies

266 The black rot of the grape and its control

272 Fire blight of pears, apples, quinces, etc.

273 The effect of fertilizers applied to timothy

on the corn crop following it

282 Seven methods of feeding young chickens

283 The control of insect pests and plant

diseases

285 The cause of "apoplexy" in winter-fed

lambs

286 The snow-white linden moth
289 Lime-sulfur as a summer spray

291 The apple red bugs

292 Cauliflower and brussels sprouts on Long

Island

293 The black rot disease of grapes

295 An agricultural survey of Tompkins
county

297 Studies of variation in plants

298 The packing of apples in boxes
"301 Sweet pea studies — I

302 Notes from the agricultural survey in

Tompkins county

303 The cell content of milk

305 The cause of "apoplexy" in winter-fed

lambs
307 An apple orchard survey of Ontario

county

309 The produ ction of ' ' hothouse ' ' 1 ambs

310 Soy beans as a supplementary silage crop

3 1 1 The fruit-tree leaf-roller

312 Germination of seed as affected by sulfuric

acid treatment

313 The production of new and improved vari-

eties of timothy

314 Cooperative tests of corn varieties

316 Frosts in New York

317 Further experiments on the economic value

of root crops for New York

318 Constitutional vigor in poultry

320 Sweet pea studies— III. Culture of the

sweet pea

321 Computing rations for farm animals

i Testing the germination of seed corn

3 Some essentials in cheese-making

4 Soil drainage and fertility

7 The relation of lime to soil improvement

8 The elm leaf -beetle

9 Orange hawkweed or paint brush
ii Helps for the dairy butter-maker

The chemical analysis of soil
(Departmental Animal Husbandry circular)

The formation of cow testing associations
Propagation of starter for butter making and

cheese making
Working plans of Cornell poultry houses

Address

MAILING ROOM

COLLEGE OF AGRICULTURE
ITHACA, N.

f

NOVEMBER, 1910

BULLETIN 286

CORNELL UNIVERSITY

AGRICULTURAL EXPERIMENT STATION OF

THE COLLEGE OF AGRICULTURE

Department of Entomology (Extension Work)
THE SNOW-WHITE LINDEN MOTH

BY GLENN W. HERRICK

ITHACA, N. Y.
PUBLISHED BY THE UNIVERSITY

ORGANIZATION

OF THE CORNELL UNIVERSITY AGRICULTURAL EXPERIMENT
STATION.

BOARD OF CONTROL
THE TRUSTEES OF THE UNIVERSITY

THE AGRICULTURAL COLLEGE AND STATION COUNCIL

JACOB GOULD SCHURMAN, President of the University.

ROBERT H. TREMAN, Trustee of the University.

LIBERTY H. BAILEY, Director of the College and Experiment Station.

EMMONS L. WILLIAMS, Treasurer of the University.

JOHN H. COMSTOCK, Professor of Entomology.

HENRY H. WING, Professor of Animal Husbandry.

EXPERIMENTING STAFF

LIBERTY H. BAILEY, Director.
ALBERT R. MANN, Secretary.
JOHN HENRY COMSTOCK, Entomology.
HENRY H. WING, Animal Husbandry.
JOHN CRAIG, Horticulture.
T. LYTTLETON LYON, Soil Technology.
HERBERT J. WEBBER, Plant-Breeding.
BENJAMIN M. DUGGAR, Plant Physiology.
JOHN L. STONE, Farm Practice.
JAMES E. RICE, Poultry Husbandry.
GEORGE W. CAVANAUGH, Chemistry.
ELMER O. PIPPIN. Soil Technology.
WILLIAM A. STOCKING, Jr., Dairy Industry.
HERBERT H. WHETZEL, Plant Pathology.
G. F. WARREN, Farm Management.
CHARLES S. WILSON, Pomology.
GLENN W. HERRICK, Entomology.
LOWELL B. JUDSON, Horticulture.
HOWARD W. RILEY, Farm Mechanics.
MERRITT W. HARPER, Animal Husbandry.
JAMES A. BIZZELL, Soil Technology.
CYRUS R. CROSBY, Entomology.
CLARENCE A. ROGERS, Poultry Husbandry.
PAUL J. WHITE, Tarm Crops.
DONALD REDDICK, Plant Pathology.
HAROLD E. ROSS, Dairy Industry.
HARRY H. LOVE, Plant- Breeding.
ARTHUR W. GILBERT, Plant-Breeding.
ELMER S. SAVAGE, Animal Husbandry.
E. S. GUTHRIE, Buttermaking.
EDWARD R. MINNS, Farm Practice.
PAUL WORK, Horticulture.
LEWIS KNUDSON, Plant Physiology.
K. C. LIVERMORE, Farm Management.

The regular bulletins of the Station are sent free to persons residing in New-
York State who request them.

THE SNOW-WHITE LINDEN MOTH

Ennomos subsignarius Hiibn.
Order, Lepidoptera; superfamily, Geometrina

A half century ago the snow-white linden moth was a conspicuous
insect in some of our Eastern cities and its caterpillars were very abun-
dant and exceedingly injurious to shade-trees. From 1857 to 1870
the shade-trees of Brooklyn, N. Y., and Philadelphia, Pa., were annually
subjected to defoliation by this insect. To check its increase, the Eng-
lish sparrow was introduced from Europe, and so well did this bird
do its work that for nearly a half century we have heard almost nothing
about this insect as a shade-tree pest. During this time there has been
an occasional reference to it as a forest-tree despoiler, but it was not
until 1907 that it again appeared as a serious pest, in New York State
at least. During that year it seriously injured forests in the Catskills
and the Adirondacks. In 1908 and 1909 it was again very abundant
and seriously injurious, and now in 1910 it promises to be as prevalent
as ever. During the last two years, in rearing large numbers of the
moths the writer has been able to find but one single specimen of a
parasite. It may be that the absence of parasites is the main reason
for the great abundance of this insect. At any rate, we must conclude
that the environments, climatic conditions, and other factors have been
especially favorable for this insect during the past four or five years.
Just how long it will continue in its present abundance, how widely it
will spread, and whether it will eventually become a pest .to our fruit-
trees and ornamental plants, are questions the answers to which we
shall await with much interest and considerable anxiety.

THE NAME

This insect has masqueraded under several names during its career
with the scientists. It was first named in 1806 by Hiibner, who called
it Eudalimia subsignaria. About a half century afterward, T. W.
Harris, in a paper in Hovey's Magazine of Horticulture, says, "This
species not having been scientifically described or named before may
be called Geometra niveoser ice aria, the snow-white silky Geometer."
In 1857, Guenee placed it in the genus Ennomos. Four years later,
Mr. J. B. Jones, in a communication to the Entomological Society of
Philadelphia, referred to it as Geometra niveosericearia, and also gave it

52 BULLETIN 286

the common name of "measure-worm," although it had no more claim
to this particular appellation than many other caterpillars of the same
family. Packard, in a discussion of the insect in 1869, gave it Guenee's
old name again, Ennomos subsignaria, but in a subsequent and more
extended discussion in 1876 changed it to an entirely new genus, Eugenia
subsignaria. Finally, in 1891, Dr. J. B. Smith, in his "List of Lepi-
doptera of Boreal America," listed it under the name, Ennomos sub-
signarius, and under this it has since remained.

Dr. Lintner, in 1882, first proposed the common name of snow-white
linden moth because of its snow-white color and its chief depredations,
as he then supposed, on the linden tree. It was soon found however,
that it attacked other trees quite as seriously and extensively as the
linden, but since the name was as appropriate as any, it has clung to
the insect to the present day.

HISTORY OF THE SNOW-WHITE LINDEN MOTH

Early history. — The snow-white linden moth was first described in
1806 and has been known to science ever since; but it was not until
about 1860 that it began to attract attention in this country as a serious
pest. In 1855, T. W. Harris discusses the abundance of the larvae in
the city of Brooklyn and says that a correspondent writes that the
"worms" were first seen in the city "ten years ago," since which time
they have appeared at the regular season every year. In 1861, Dr. J.
B. Jones wrote a report on the measure worms which infest the trees
of Brooklyn, with suggestions for treatment. In the same year, the
citizens of Brooklyn became so excited over the increase of this measur-
ing worm that the Common Council seriously discussed a resolution
compelling the destruction of all linden trees on the streets of the city.
In a subsequent examination, however, the caterpillars were found on
so many other varieties of shade-trees that it was seen that no per-
manent good could be accomplished by the destruction of the linden
trees and the resolution was 'laid on the table indefinitely. In 1881,
Mr. Grote wrote that, when he lived in Brooklyn in 1857, this measuring
worm was so abundant "that the horse-chestnuts, elms, and maples,
the latter especially, became completely defoliated, and the brown
measuring worms used to hang down and cover the sidewalks ultimately
to the great discomfort of the passers by." It is said that this condition
continued until the introduction of the English sparrow, which is con-
sidered to have destroyed the caterpillars and held the pest in check.

In. 1880 the pest was discovered in Georgia. Professor Comstock
reported the caterpillars as destroying forests of hickory and chestnut

THE SNOW-WHITE LINDEN MOTH 53

and doing much damage to fruit-trees. Since that time we have heard
mention of the insect only now and then until within the last three years.

Later history. — On July 6th, 1909, we received from a correspondent
at Cooks Falls, N. Y., the following letter concerning this pest: "Last
year there appeared in this community a worm somewhat similar to
the common apple tree worm and known locally as the 'beech' worm
from its habit of eating the leaves of the beech tree. We thought it
would die out over winter, but have been disappointed in this hope.
It is again eating the foliage of the same trees it stripped last year and
is threatening large tracts of very valuable timber land. While it
appears to prefer the beech leaves it quite often attacks maple, birch,
etc. As our interests in timber land are considerable, we write to enlist
your aid in determining what species of worm this is, and how its ravages
can be stopped." In response to this appeal, the writer made a per-
sonal inspection of the infested area and found a fine forest of beech,
maple, and other wood, over five hundred acres in extent, literally
stripped of leaves by the larvae of this moth. The owner said that
they were so numerous that the dropping of the excrement sounded
like rain pattering on the leaves. The undergrowth was almost as
bare as it would be in winter. The young beeches had suffered more
severely than any other trees and most of them were entirely bare of
leaves. Hundreds of empty pupal cases, partly rolledr-up in eaten leaves,
were hanging to the trees. The caterpillars had covered a certain area
on the top of this particular mountain and part way down one side.
The line limiting their injuries was clear and evident to the eye long
before we reached the actual area. For two successive years this forest
had been denuded and the larvae were just as abundant this year (1910)
as ever.

On July 9, 1909, a correspondent at Arena, N. Y., about twenty
miles from Cooks Falls, wrote that the caterpillars "are working mostly
on beech, ash, birch, and maple. In fact, nothing comes amiss to them.
In driving through the town of Hardenburgh, Ulster Co., I noticed
the trees were literally stripped of their foliage and a fence running in
the woods was so loaded with them (caterpillars) you could not see
the rails. They hang by webs on the trees, and looking through the
forest appears like looking through smoke or a fog." This same cor-
respondent wrote on May i6th, 1910, nearly a year later, that the trees
were again "literally covered with the very small caterpillars and that
if nothing can be done to check them the Catskills are doomed." The
. pest is evidently widely distributed, for there are reports of its injuries
in Ulster Co., Sullivan Co., and also in the forests of the Adirondacks.

54

BULLETIN 286

In his report for 1908, Dr. Felt says that the Forester, E. S. Woodruff,
reports the beeches on a tract of over two square miles as completely
defoliated. The caterpillars seem to attack the beeches first, but finally
spread to the birches and maples. (Fig. 54).

One of the most remarkable phases of this pest were the flights of
great swarms of the snow-white moths in cities and towns throughout
the eastern part of the State and in New Jersey. In New York City
the effect was compared to a snowstorm in mid-summer. Myriads
of the moths fluttered about the electric lights. Dr. John B. Smith

FIG. 54. — Caterpillars of the snow-white linden moth on maple

says that on the evening of July ryth, Newark, Elizabeth, and Pater-
son, N. J., had the same experience. On the morning after the flight,
however, nothing remained except great numbers of snow-white wings
without bodies, showing the work of the English sparrow, and probably
of other birds and destroyers. These flights are remarkable since the
presence of the caterpillars had not previously been noticed in these
towns and cities. It seems probable that the moths must have flown
long distances from the feeding places of the caterpillars in the forests.
During the latter part of July, 1909, Ithaca and several other cities

THE SNOW-WHITE LINDEN MOTH 55

in the central part of the State experienced similar flights of myriads
of the spruce bud moths. These moths could not have bred in such
numbers on ornamental spruces in the near vicinity of the towns invaded
but must have come from some forested areas, perhaps at long distances
from the towns invaded. Thus we have an undoubted second instance of
a moth which has certainly flown long distances from the feeding places
of its larvae.

THE DANGER AS A FRUIT PEST

The first reference to this insect as a fruit pest that the writer finds
is by Thomas in his Second Illinois Report, in which he says that he
twice found the larvae on apple trees, though not in large numbers,
and had reared them to the perfect insect on the leaves of this tree.
In 1880, Comstock, quoting a correspondent, says that the larvae were
damaging fruit-trees in Georgia. In 1882, Dodge, in the Canadian
Entomologist, quoting from the same correspondent in Georgia, writes
that the "apple trees in June last were as destitute of leaves as in mid-
winter, the fruit growing to the size of marbles and falling off."

In 1904, Garman writes of this insect as an important pest of the
apple tree in Muhlenberg Co., Kentucky. It was especially injurious
in 1903 but not so serious in 1904, due probably to the work of parasites.
Again, in 1908, Garman treats of this pest as a serious one on apple
trees and says that this species "is sometimes very common locally
and may defoliate whole orchards at times." In his 23rd Report, Felt
says very significantly, "It would not be surprising if a number of
outbreaks, hitherto attributed to our more common canker worms,
were in reality the work of this species/'

It is quite evident that we have in this insect a possible future fruit-
tree pest of considerable importance. It apparently used to be con-
fined to the shade-trees of our cities but it has now almost entirely
deserted these for our forest-trees. It would not be at all surprising in
view of the history of this insect if the future should see it migrating
from the forest-trees to our fruit-trees and becoming a serious pest.

DISTRIBUTION

Evidently this insect is widely distributed over the Middle and East-
ern United States, and it occurs in Canada. It has been recorded from
Nova Scotia to Georgia and westward through Michigan, Kentucky,
Iowa and Colorado. In New York State, the moths have been reported
from Delaware, Ulster, Sullivan, Rensselaer, Albany, Columbia, Sara-
toga, Schenectady, Herkimer, Fulton and Oneida Counties, and from
the northeastern part of the State in the Adirondacks.

56 BULLETIN 286

FOOD PLANTS

The larvae infest a great variety of forest-trees, apparently some-
what preferring beech and maple. They have been found on elm,
linden, chestnut, hickory, ash, apple, birch, and others.

V

THE LIFE HISTORY AND HABITS OF THE INSECT

This insect requires nearly a year to pass through its life history.
It is said that in Georgia the eggs were laid on the leaves as though
there might be a second brood or generation in a season. It would
seem from a study of the insect in New York that this must have been
due to the carelessness of the female moths and can hardly be taken
as an evidence of a second brood. At any rate, there is only one brood
in New York State each year; and this is fortunate. If this pest could
pass through its life history and produce a generation every two or
three months, our forests would surely be doomed to destruction.

The eggs of the female moth are laid on the under sides of the branches
— as often on the upper branches of the smaller trees, at least, as on the
lower. In a rather hasty search, the writer found the eggs laid on the
beech only. However, a correspondent at Arena, N. Y., has sent many
eggs deposited on maple. The eggs are always deposited at an oblique
angle to the surface of the bark and lean against each other like a pile
of leaning bricks. They are laid in masses of 20 to 100 or even more,
and are stuck so securely to the branch that in 1909 the writer found
still adhering to the trees the empty shells of quite as many old egg
masses of 1908 as there were new ones of 1909. The eggs are deposited
on the branches in the latter part of June and first part of July, and
remain unaffected by snow, rain, or extremes of temperature until the
following April and May, nearly a year after deposition.

The eggs are about one twenty- fifth of an inch in length, barrel shaped,
often more or less flattened on the sides, light olive when first deposited
but later becoming darker in color, with a conspicuous ring at the free
extremity. They occur in irregular masses, long and narrow if the
branch is small but spread out if the surface is large (Fig. 55).

Eggs brought from Cooks Falls in August, 1909, were placed out-
doors under natural conditions and began to hatch May 2nd, 1910.
Eggs sent from Cooks Falls on May nth, 1910, had not hatched, and
the writer found that the caterpillars on the mountain at Cooks Falls
had appeared two to three weeks later than at Ithaca or at Arena,
N. Y., the difference probably being due to the higher altitude and
lower temperature. Eggs at Arena, N. Y., brought into the house in

THE SNOW-WHITE LINDEN MOTH

57

FIG. 55. — The snow-white linden moth: i, egg mass, side view; 2, eggs "-enlarged;
3, eggs much enlarged; 4, larva enlarged; 5, pupa enlarged

58 BULLETIN 286

February, moistened and placed by the stove, hatched and the cater-
pillars, which were fed on leaves of Abutilon, apparently throve finely
but were not reared to maturity. Other eggs from Arena placed out-
doors under natural conditions hatched at Ithaca as early as April 23rd.

The number of eggs that may be deposited on a single tree is very
great. The number in six average clusters ran as follows: 93, 21, 44,
40, 89, and 67, respectively. Many clusters contain more eggs than
the highest of the foregoing. Scores of such egg clusters exist on many
of the trees in the infested area. Messrs. Graef and Weibe say that
they removed at least 60,000 eggs from one small maple tree in Brooklyn.

It is probably right to say that the eggs of this moth begin to hatch
in the latter half of April, and in high altitudes probably not much
before the middle of May. When a caterpillar first emerges from the
egg it is only about one-tenth of an inch in length and its general color
is green. The head, last abdominal segment, and sides of the body
are light green while the back is a darker green. In general, when
the larva is viewed from above, the two ends of the body appear light
green in color with the part between a darker olive green.

The young larvae begin at once to eat the green tender leaves.
On May 3d, the writer placed six caterpillars, just out of the egg, on
fresh tender maple leaves, each caterpillar on a leaf by itself, to watch
its habits of eating. By the morning of May 5th each one had eaten
holes through its leaf, varying from pinholes up to good sized shot
holes. In one leaf eighteen such holes had been eaten, which shows
something of the voracity of the tiny larvae. Observers who have
had the opportunity to watch these larvae in the forest say that at
first they climb to the top of the tree and to the ends of the branches
where the leaves are presumably younger and more tender. As they
grow they gradually ravage the entire tree.

The caterpillars vary considerably in color and markings. In general,
after the first molt they become dark reddish brown, in many cases
almost black, with the head and last abdominal segment red or reddish
brown and quite conspicuous. The larvae resemble the twigs of the
tree on which they are feeding, and like other "measuring worms"
have the habit of holding themselves erect and motionless like a broken
twig. The six larvae reared on separate maple leaves and receiving an
abundance of food were without exception of a beautiful pale rose
color with three distinct tubercles on the abdomen, as shown in Figs.
54, 55. Many of the caterpillars received from the infested forest trees
were of a light green color throughout and in marked contrast with
the darker ones. Full grown caterpillars that have had all the food

THE SNOW-WHITE LINDEN MOTH 59

they want become a little over two inches in length, but when they are
crowded and the food supply limited they are often less than two inches
long. During 'their growth the larvae molt five times or even six times.
Graef and Weibe record only three molts.

The caterpillars of this moth have the three pairs of true legs attached
to the thorax, but only the last two pairs of abdominal legs are present,
thus leaving the middle of the body unsupported. Hence, instead of
walking like many other caterpillars do, they move with a looping
gait and have been called "looping" caterpillars or "measuring worms."
Moreover, they have the habit of spinning a silken thread and letting
themselves down by it from the branches when the tree is suddenly
struck or jarred. Frequently they drop half way down to the ground
and remain quietly suspended in the air for a few moments, after which
they ascend to the branches above. It is said that during their great
abundance on the shade-trees in Brooklyn in the sixties much annoy-
ance was caused by this habit of dangling in the faces of pedestrians.
The following remarks of a committee from the Brooklyn Horticultural
Society anent this phase of the insect are interesting: " It would seem
to be entirely unnecessary for the committee to urge upon those who
have been constrained to traverse our streets in the latter part of June
and the early part of July, the great importance — they might almost
say the necessity — of devising and accomplishing some plan for remov-
ing the worms which dangle before their faces, are dropped upon their
clothing, or are crushed by their feet at every step. Certainly no gen-
tleman, no lady, can need to be convinced that carrying these worms
from house to house, brushing them out of the face and hair, or stopping
at the corners to pick them off with the fingers — at the risk of crushing
them in the experiment — is not a part of the privilege which one looks
for in becoming a resident of a city like this."

Six caterpillars that emerged from eggs May 3rd began spinning
their cocoons May 30, July i, 2, 3, 6 and 7, respectively, and changed
to pupae about three days after commencing the cocoons. It should
be understood that these larvae were under exceptionally favorable
surroundings so far as food was concerned. The cocoons are very flimsy
affairs and usually are made by turning over the edge of a ragged leaf
and lining the inside with a thin net-like layer of silk (Fig. 56). Graef
and Weibe say that the insects pupate on the trunks and branches of
trees, on fences, railings, lamp-posts, or almost anything they can reach.

The pupa is about five-eighths of an inch long, sometimes more, some-
times less. It is blunt and rounded at the anterior end but strongly
pointed at the posterior extremity and terminates with about six small,

6o

BULLETIN 286

-3

FIG. 56. — The snow-white linden moth: 2, moths from nature; 3, lace-like cocoon
4, pupa under the rolled edge of a leaf

THE SNOW-WHITE LINDEN MOTH 61

chitinous hooks that securely fasten the pupa to the network of threads
lining the cocoon. The pupa is of a pale brown color necked with numer-
ous black dots which in some places run together. .The six pupae,
under observation, occupied 13 to 16 days for their transformations
to adults.

The moths are pure white, and the females are somewhat larger
than the males and have thread-like antennae, while the males possess
feather-like antennae. The front wings of the male and the female
are angulated, those of the female more prominently. Packard says
that the hind wings of the male are entire. In a long series of bred
specimens, many males show notched hind wings while some are entire
in outline. The hind wings of the female are noticeably and quite
regularly notched. (Fig. 57).

FIG. 57. — Male moth at left, female at right

From the eggs brought to Ithaca from Arena and Cooks Falls we
find the moths appearing from June 16 to July ist. From caterpillars
obtained from Cooks Falls in 1909 we find the moths appearing July 18
to July 2$th. At Arena, N. Y., in 1909, the larvae were found pupating
about July ist and the moths appeared about the middle of July. It
would seem, then, that the adult moths appear from the middle of
June to the last of July, depending upon the season, altitude, and other
factors. The eggs are deposited within a few days after the moths
emerge, thus completing the life cycle.

NATURAL ENEMIES

What the natural checks of this insect are we are unable to say at
present. It is evident that some unfavorable conditions have operated

62 BULLETIN 286

to hold it in check for the last fifty years, and it is equally evident that
for the past three or four years these forces have been partly or wholly
inoperative.

The testimony regarding the activity of the English sparrow in
exterminating this pest in cities seems to show rather conclusively
that this much-disliked bird did actually bring about the destruction
of this insect. Nearly every writer on the snow-white linden moth
makes acknowledgment to the sparrow and declares that the cities
owe their freedom from this insect to that bird. We take pleasure in
again calling attention to this little-known meritorious work of the
English sparrow.

Mr. William H. Broadwell in describing the visitation of the snow-
white linden moths at Newark, N. J., on the night of July lyth, 1908,

as "a July blizzard," has the follow-
ing to say regarding the work of the
* sparrows in destroying this insect:

"Early the following morning, under
the lamps, the wings were on the
ground as thick as apple blossoms
after a storm, showing that the spar-
rows had not forgotten why they were
FIG. 58.— A parasite (Pimplacon- brought over to this COUntry some

quisitor} of the sncw-white linden ,. » n/r r>

• ^ forty years ago. Mr. Grote, in a paper

from which we have already quoted,

after discussing the great abundance of the measure worms in Brooklyn,
says further, "The advent of the English sparrow changed all this.
The naked brown larvae of subsignaria disappeared before them."

In 1880, Mr. G. H. French of Carbondale, 111., bred five males and
seven females of a minute Hymenopterous parasite, Macrocentus irides-
cens, from two caterpillars, which he took to be Ennomos subsignaria,
found on an elm tree. We have not been fortunate enough to find
this parasite present in any of the caterpillars reared by us. We have,
however, bred one single specimen of a common parasite, Pimpla con-
quisitor (Fig. 58), from the pupae of the snow-white linden moth. Since
only the one specimen has been obtained from the scores of pupae we
have had, it will be seen that this parasite is not abundant enough
'yet to be of any great service as a check. Mr. Harris says that Chalcis
ovata, a small parasite, has also been reared from the pupae.

It may well be that the great and wanton destruction of birds is
one cause of the abnormal abundance of this insect. If one bird is
so efficient in the control of this pest, as the evidence shows it to have.

THE SNOW-WHITE LINDEN MOTH 63

been, then why may we not legitimately expect a great deal of our native
birds in this respect ? Undoubtedly one of the most efficient and feasible
means for the control of this insect in our forests will be the better
protection of our native birds.

METHODS OF CONTROL

In the control of this pest in shade-trees, spraying with arsenate of
lead, 3 pounds to 50 gallons of water, would probably be very effective.
If it ever becomes injurious to apple trees in this State, the same method
of control would have to be followed. The trees should be sprayed
early while the caterpillars are small, as the poison will be much more
effective then.

As we have already noted, the caterpillars have the habit of sud-
denly dropping to the ground in great numbers when the trees are jarred.
On small trees, hundreds of the caterpillars may be jarred on to sheets
and then destroyed. Unfortunately, the young larvae are not so sus-
ceptible to this kind of treatment, and if one waits until they become
large much of the damage will already have been done.

Tho masses of eggs are very conspicuous objects and could easily
be found on the branches and scraped off. In the case of small trees
much good could be accomplished in this manner. On large trees it
would be more difficult to collect the eggs.

In forests there seems no practicable way of controlling this pest. In
case of the particular forest area mentioned at Cooks Falls, the wood
is being grown for the manufacture of certain wood chemicals. In this
instance it may be best to cut off the present growth of timber and
use it for the distillation products before it dies as a result of the annual
defoliation to which it has been subject for the past two years.

BIBLIOGRAPHY

1806. Hiibner, J. — Samml. Exot. Schmett., ii. Taf. 429. (Lists Eudalimia

subsignaria.)

1855. Harris, T. W. — Mag. of Hort. (Hovey). Vol. 21, pp. 418-423.
1857. Guenee. — Lepidopteres nocturnes. Vol. IX, p. 181. (Description of

moth and larva.)
1860. Morris, J. G.— Cat. of the Descr. Lep. of N. A., J>. 56.

1860. Walker, F. — List of the Lepidopterous Insects in the British Museum,

Vol. 20, p. 209.

1861. Jones, J. B. — Proc. Ent. Soc. Phil., i, p. 31. (Report on the measure

worm.)

1861. Glover, Townend. — U. S. Dept. Agri. Rpt., p. 554. (Mentioned.)

1862. Graef and Weibe. — Rpt. Brooklyn Hort. Soc., 1862. (Report on the

measure worm.)
1868. Packard, A. S.— Amer. Nat. II, p. 333.

1869. Guide to the Study of Insects, p. 321.

1872. Lintner, J. A. — Ent. Contrib., i, p. 77' (Listed.)
1874. Leconte, J. L. Pop. Sc. Month., 1874, p. 381.

64 BULLETIN 286

1874. — Proc. A. A. A. S., Pt. 2, pp, 23-44.

1876. Packard, A. S. — Monograph of the Geometric! Moths of the United States.

Geol. Surv. of the Terr., Vol. X, p. 528.

1877. French, G. H. —Trans. Dpt. Agri. 111., XV., p. 243.

1878. — Nox. and Ben. Ins. 111., 7th Rpt., p. 243. (Larva des-

cribed and adult as Eugenia.)

1880. — Can. Ent., Vol. 12, p. 43. (Parasite bred from Ennomos —

Macrocentus iridescens.)

1881. Packard, A. S. — Bull. U. S. Ent. Comm., VII, p. 62. (Brief description.)

1881. Comstock, J. H. — U. S. Dpt. Agr. Rpt., 1880, p. 271. (Injuries as Eugonia.)

1882. Dodge, C. R. — Can. Ent. Vol. XIV, p. 30. (A new apple pest.)
1882. Grote.— Bull. Geol. Surv. Terr., Hayden, VI, p. 588.

1882. Dodge, C. R. — Ent. Soc. Ont. Rpt., i3th, p. 18. (Same as above.)
1882. Packard, A. S. — Fifth Rpt. Ent. Comm., pp. 232, 306, 329, 354 and 481.

1882. Lintner, J. A. — N. Y. State Ent. ist Rpt., p. 329. (Proposes name of

snow-white linden moth.)

1883. Saunders, W. — Insects Injurious to Fruits, p. in. (Brief account.)
1883. Grote, A. R. — Can. Ent. Vol. XV, p. 235. (Sparrows eating caterpillars.)

1885. Lintner, J. A. — N. Y. State Ent. 2nd Rpt., p. 76. (List of food plants.)

1886. Walsh, B. — Pract. Ent. i, p. 57. (Life history, etc.)

1891. Smith, J. B. — List of Lepidoptera, p. 65.

1892. Meyrick, E. — Trans Ent. Soc. London, pp. 53—140. (Classification of

Geometrina of Europe.)

1893. Lintner, J. A. — Insect Life, Vol. 6, p. 184. (Mentioned as Eugonia.)

1895. Meyrick, E. — Handbook of British Lepidoptera.

1896. Hulst, G. D.— Trans. Amer. Ent. Soc., Vol. XXIII, p. 371. (Synonomy.)
1896. Lintner, J. A. — N. Y. State Ent. nth Rpt., .p. 121. (Mentioned.)
1896. Osborn, Herbert. — U. S. Dept. Agri. Div. Ent. Bull. 6 n. s., p. 80. (Injur-
ing forests.)

1899. Lugger, Otto. — Minn. Agri. Expt. Stat. Bull. 61, p. 230. (Brief notice.)

1899. Smith, J. B. — Insects of New Jersey, p. 449.

1902. Dyar, H. G. — List of N. A. Lep., p. 336.

1903. Holland, W. J. — Moth Book, p. 348. (Distribution.)

1904. Garman, H. — Ken. Agri. Expt. Stat. Bull. 116, p. 79. (Life history on

apple.)
1904. Kirby, W. F. — Hubner's Exot. Schmett., Ill, Additional notes, p. 164.

(Lists Eudalimia subsignaria. Gives synonyms

Ennomos subsignaria and Geometrina niveoseri-

cearia.)

1904. Gibson, Arthur. — Rpt. Ent. Soc. Ont., 34th, p. 56. (Brief life history.)
1906. Felt, E. P. — N. Y. State Mus. Mem. 8, Vol. 2, p. 725. (Food plants.)
1908. —Jour. EC. Ent. Vol. i, No. 5, p. 330. (Dist. in N. Y. State.)

1908. Jour. EC. Ent. Vol. 2, No. 4, p. 306. (Presence in N. Y. State.)

1908. — N. Y. State Ent. Rpt. 23rd, p. 23. (Descrip., life history, etc.)

1908. Smith, J. B. — New Jersey State Ent. Rpt., p. 317. (Unusual abundance.)
1908. Britton, W. E. — Conn. State Ent. Rpt. 8th, p. 842. (Abundance of.)
1908. Broadwell, W. H. — Can. Ent. Vol. XL, pp. 327-328.

1908. Garman, H. — Ken. Agri. Expt. Stat. Bull. 133, p. 29. (Habits and life

history.)

1909. Felt, E. P. — Jour. EC. Ent., p. 308. (Reference.)

1909. — N. Y. State Ent. Rpt. 24th, p. 51. (Injuries in 1908.)

1909. 'Broadwell, W. H.— Can. Ent. Vol. XLI, p. 392.

1909. Winn, A. F. — Ent. Soc. Ont. Rpt. 4oth, p. 56. (Unusual abundance of.)

NOVEMBER, 1910

CIRCULAR No. 8

CORNELL UNIVERSITY

AGRICULTURAL EXPERIMENT STATION OF

THE COLLEGE OF AGRICULTURE

Department of Entomology (Extension Work)

Fir,

THE ELM LEAF-BEETLE

GLENN W. HERRICK

About 1834 there was introduced into the city of
Baltimore, from somewhere in Europe, a small in-
conspicuous beetle whose food plant at home had
been the European elms. It attracted no particular
attention until about four years later, when it came
into prominence as a serious enemy of the elms in
this Maryland city. Since that time it has gradually
extended its territory until now it is found as far
north as Massachusetts and New York and westward
to Ohio and Kentucky. In
— \n adult NGW York State it is destruc-
eim leaf-beetle. tive in the eastern and cen-
tral sections, and very likely

will gradually extend its activity until it

covers the greater part of the State.

THE APPEARANCE OF THE BEETLE, AND ITS
WORK

The insect is about one-fourth of an inch long.
In general, it is yellowish or brownish yellow
in color, with a dark line along each side of
its back (Fig. i). Its color varies somewhat,
and the over-wintering beetles are often so
dark colored that the brownish yellow almost
disappears and the black lines are hardly *
noticeable. In its normal coloring it is quite
likely to be confused with the common striped

cucumber beetle, although it is considerably ^ 2 _Adult beetles eating
larger. leaf in the spring.

When the beetle first awakens in the spring from its long winter
sleep, it flies to the elm trees just bursting into leaf and takes its first
meal by eating small, irregular holes through the young, tender leaves
(Fig. 2). After feeding a few days, the orange-colored eggs are depos-
ited on the leaves and these in a few days more hatch into the tiny
black and yellow grubs (Fig. 3). These grubs are the chief culprits.
They work on both surfaces of the leaves, although mostly on the under
sides, and eat so ravenously that in a few weeks nothing remains of the
leaves except a bare network of veins. The effect on the leaves is serious,
for they turn brown, curl, and finally fall from the trees. If the trees
are vigorous enough and the season isTpropitious, a second crop of
leaves is put out, but these may meet the same fate as the first.

FIG. 3. — Young grubs eating leaf.

EXTENT OF ITS INJURIES

It was estimated that in 1898 1,000 fine elms were killed in the city
of Albany and that in Troy the conditions were even worse. Similar
condition's obtained in dozens of other towns in the Hudson Valley
and along the Mohawk River. The writer has been told that a majority
bf the magnificent elms in Harvard Yard have been destroyed within
the last two or three years by the attacks of these small pests. There
is danger that through inaction and apathy the splendid elms of our
own City and Campus will suffer a like fate. Some of them are now
probably past any effort to save them.

FIG .4.— Eggs natural size, and much enlarged.

Undoubtedly the elm leaf-
beetle must be regarded as the
most serious pest to shade-
trees in this State. It prob-
ably destroys more shade-trees,
certainly more elm trees, than
all other insect pests com-
bined.

STORY OF ITS LIFE

In the fall of the year many
of the full-grown beetles, in
searching for snug crannies in
which to pass the winter, find
their way into* dwelling houses, congregating especially in the attics
where they may often be found by the score. Housekeepers are some-
times alarmed when they see so many of these beetles crawling on the
window panes, walls, and ceilings of the rooms, likely thinking that
here is another household pest. Fortunately, so far as the writer
knows, these insects do not injure household articles of any descrip-
tion. Other individuals hide away under loose pieces of bark on trees,
in cracks in fences and telegraph poles, in outhouses, sheds, and in
any other sheltered places they are able to find. Here they remain in
a quiet, inactive condition through the long winter months. With the

warm days of spring, the bee-
tles awake and begin crawling
about on the walks and on the
window panes.

As soon as the leaves begin
to appear, the insects fly to the
trees for their first spring meal.
After feeding for some time
they deposit their conspicuous
orange-colored eggs (Fig. 4) in
clusters of five to twenty-five
on the undersides of the leaves.
Each egg is flask-shaped and
stands upright with its larger
end attached to the leaf. The

FIG. 5.— Grubs nearly grown, eggs hatch in five or six days

during hot weather, but in cool

FIG. 6. — Pupa of the elm
leaf -beetle .

weather this period may be prolonged several
days. The writer found that in Ithaca, last year,
the majority of the eggs were laid during the first
three weeks of June. By June 2oth the young
grubs wrere appearing in force. The grubs eat
ravenously, increase in size very fast, and com-
plete their growth in fifteen to twenty days (Fig. 5).
When full grown they either crawl down the trunk
of the tree or drop from the ends of the branches.
At the bases of the trunks many of the larvae
transform to the yellow pupae (Fig. 6). Some-
times they are so numerous that the golden pupae

lie an inch deep about the foot of the tree. Others
transform in crevices of the bark, especially if the

trunk is rough, others go to the gutters, while others seek shelter in
crevices of the sidewalk and wherever they can find hiding places. The
quiet, inactive pupae lie motionless for six to ten days and then trans-
form to the adult beetles, thus completing the life round of one genera-
tion. Our observations show that in Ithaca we have one generation,
with a possible second, the latter, however, being so small as to cause
no serious damage.

METHODS OF CONTROL

The elm leaf-beetle can be controlled effectively only, by spraying
the trees with an arsenical poison, preferably arsenate of lead, at the
rate of three or four pounds to fifty gallons of water. (See Fig. 7 for

FIG. 7. — Sprayed elm at right, unsprayed at left.

-I^!lfe*<;:> ;

•<•--••-•• •••'••\te':

sprayed and tmsprayed trees.) In
order to be most effective, two spray-
ings each year should be given,
especially during the first season. If
the work is well done the trees may
not need another application for a
year or two.

The first spraying should be made
while the leaves are unfolding and
expanding, to kill as many of the
adult beetles as possible before they
commit injury or lay their eggs. The
second spraying should be made about
the second week in June in this locality,
to kill the young grubs as soon as
they begin to feed. Since they feed
mainly on the lower surfaces of the
leaves the poison mixture should be
applied as much as possible to the undersides of the leaves.

FIG. 8. — Hand-spray^ng outfit.

SPRAYING APPARATUS

Low and medium-sized trees can be sprayed very well with certain
hand-spraying outfits, like the one in Fig. 8. A high step-ladder with
an extension rod to which the nozzle may be attached will facilitate
the work greatly. A nozzle capable of throwing a fine or coarse spray
will probably be best.

For large trees a power spraying outfit will be necessary. There
are several makes of gasoline power sprayers on the market that can
be bought for $250.00 to $300.00 (Fig. 9).

COST OF SPRAYING

Available data on this subject
show that it costs twenty-five to
sixty cents for a single applica-
tion to a large tree if the work
is done privately. If the work is
performed on a large scale by a
contractor it can be done more
cheaply. If one can contract to
have his trees sprayed twice in
FIG. 9. —Power-spraying out-fit. °ne season for fifty cents a tree,

for large trees, it would seem to be a reasonable price. If the trees are
small, they should be sprayed for less.

Figures 2, 3, 4 and 5 are from photographs by M. V. Slingerlarid. The draw-
ings were made by Miss Anna Stryke.

Bulletin 160. "**inuary, 1899.

Cornell University Agricultural Experiment Station.

ITHACA, N. Y.

HORTICULTURAL DIVISION.

RURAL SCHOOL

GROUNDS.

By L. H. BAILEY.

PUBLISHED BY THE UNIVERSITY,

ITHACA, N. Y,

1899-

ORGANIZATION.

BOARD OF CONTROL:

THE TRUSTEES OF THE UNIVERSITY.

THE AGRICULTURAL COLLEGE AND STATION COUNCIL.

JACOB GOULD SCHURMAN, President of the University.

FRANKLIN C. CORNELL, Trustee of the University.

ISAAC. P. ROBERTS, Director of the College and 'Experiment Station.

EMMONS L. WILLIAMS, Treasurer of the University.

LIBERTY H. BAILEY, Professor of Horticulture.

JOHN H. COMSTOCK, Professor of Entomology.

STATION AND UNIVERSITY EXTENSION STAFF.

I. P. ROBERTS, Agriculture.

G. C. CALDWELL, Chemistry.

JAMES LAW, Veterinary Science.

J. H. COMSTOCK, Entomology.

L. H. BAILEY, Horticulture.

H. H. WING, Dairy Husbandry.

G. F. ATKINSON, Botany.

M. V. SLINGERLAND, Entomology.

G. W. CAVANAUGH, Chemistry.

L. A. CLINTON, Agriculture.

B M. DUGGAR, Botany.

J. W. SPENCER, Extension Work.

J. L. STONE, Sugar Beet Investigation.

MISS M. F. ROGERS, Nature-Study.

A. L. KNISELY, Chemistry.

C. E. HUNN, Gardening.

W. W. HALL, Dairy Husbandry.

W. E. GRIFFITHS, Dairy Husbandry.

A. R. WARD, Dairy Bacteriology.

L. ANDERSON, Dairy Husbandry.

F. A. STEVENS, Demonstrator.

OFFICERS OF THE STATION.

I. P. ROBERTS, Director.
E. L. WILLIAMS, Treasurer.
EDWARD A. BUTLER, Clerk.

CORNELL UNIVERSITY, January 2, 1899.
HONORABLE COMMISSIONER OF AGRICULTURE, ALBANY.

Sir : In the effort to extend the teaching of nature and to
popularize farming subjects, we have found the nature-study
leaflets to be invaluable. These leaflets are now so well estab-
lished in the estimation of New York teachers that we are obliged
to print them in editions of 25,000. These afford subject-matter
for direct teaching. But the surroundings of the child should also
be such as to interest him in rural subjects. The home and the
school premises should supplement the explicit work of the teacher.

We have endeavored to provide suggestions for the improve-
ment of home surroundings in a number of bulletins ; and we
hope that more will follow. For many years, Professor Bailey
has been studying the problem of the improvement of rural
school grounds, but it is only now that he has felt that the time
is ripe for a distinct movement in this direction. This bul-
letin is the first move. It strikes at one of the greatest evils
connected with the education of the farmer's children. We hope
to follow up the movement, and eventually to give suggestions
for the interior of the schoolhouse.

These recommendations are the result of long study of trees
and shrubs as adapted to New York State, and of the principles
of landscape gardening. The report is submitted for publication
as a bulletin under Chapter 67 of the L/aws of 1898.

I. P. ROBERTS, Director.

2\.— Where children are taught. An actual example, in one of the most
prosperous fruit-growing sections of New York.

22. — ^ suggestion in planting.

HINTS ON RURAL SCHOOL GROUNDS.

One's training for the work of life is begun in the home and
fostered in the school. This training is the result of a direct and
conscious effort on the part of the parent and teacher, combined
with the indirect result of the surroundings in which the child is
placed. The surroundings are more potent than we think ; and
they are usually neglected. It is probable that the antipathy to

23. — The beginning and the end,— school house and graveyard. In
eastern New York.

farm life is formed before the child is able to reason on the
subject. An attractive play-ground will do more than a profit-
able wheat crop to keep the child on the farm.

a. THE FACT.

Bare, harsh, cheerless, immodest, — these are the facts about
the average rural school ground. Observe Fig. 21.

Children cannot be forced to like the school. They like it only

276

BULLETIN 160.

when it is worth liking. And when they like it, they learn.
The fanciest school apparatus will not atone for a charmless
school ground. A child should not be blamed for playing truant
if he is sent to school in a graveyard. Observe Fig. 23.

It would seem that land is very precious. Very little of it
can be afforded for a school ground. A quarter of an acre of
good land will raise four bushels of wheat, and this wheat may
be worth three or four dollars a year. We cannot afford to de-

iBgE

.

24. — A suggestion for a simple little schoolhouse.

vote such valuable property to children. We can find a bit of
swamp, or a sand hill, or a treeless waste. The first district
school I taught was on a heartless hillside. The premises had two
or three disconsolate oaks, and an old barrel was stuck in the top
of one of them. The second school was on an island in a swamp.
The mosquitoes loved it.

The school building is generally little more than a large box.
It has not even the charm of proper proportions. A different
shape, with the same cost, might have made an attractive
building. Even a little attention to design might make a great

HINTS ON RURAL SCHOOL GROUNDS. 277

difference in the looks of a schoolhouse ; and the mere looks
of a schoolhouse has a wonderful influence on the child. The
railroad corporation likes to build good-looking station-houses,
although they have no greater capacity than homely ones. I
asked an architect for a simple plan of a cheap school house.
He gave me Fig. 24. Plans for the improvement of shoolhouses may
be obtained of the Superintendent of Public Instruction, Albany.

The following sentences are extracted from the ' ' Report of
the Committee of Twelve on Rural Schools," of the National
Educational Association (1897) :

' The rural schoolhouse, generally speaking, in its' character
and surroundings is depressing and degrading. There is nothing
about it calculated to cultivate a taste for the beautiful in art or
nature. ' '

"If children are daily surrounded by those influences that
elevate them, that make them clean and well-ordered, that make
them love flowers, and pictures, and proper decorations, they at
last reach that degree of culture where nothing else will please
them. When they grow up and have homes of their own, they
must have them clean, neat, bright with pictures, and fringed
with shade trees and flowers, for they have been brought up to
be happy in no other environment."

' The rural schoolhouse should be built in accordance with the
laws of sanitation and modern civilization. It never will be
until the State, speaking through the Supervisor, compels it as
a prerequisite for receiving a share of the public funds."

b. HOW TO BKGIN A REFORM.

We will assume that there is one person in each rural school
district who desires to renovate and improve the school premises.
There may be two. If this person is the school commissioner or
the teacher, so much the better.

Let this person call a meeting of the patrons at the school-
house. Lay before the people the necessity of improving the
premises. Quote the opinions of intelligent persons respecting
the degrading influence of wretched surroundings ; or even read
extracts from this bulletin. The cooperation of the most

278 BULLETIN 160

influential men of the district should be secured before the
meeting is called.

Propose a "bee" for improving the school grounds. John
Smith will agree to repair the fence (or take it away, if it is not
needed). Jones will plow and harrow the ground, if plowing
is necessary. Brown will sow the grass seed. Black and Green
and White will go about the neighborhood with their teams
for trees and bushes. Some of these may be got in the edges of
the woods, but many of the bushes can be picked up in front
yards. Others will donate their labor towards grading, planting,
and cleaning up the place.

The whole thing can be done in one day. Perhaps Arbor Day
can be chosen.

C. THE PLAN OF THE PLACE.

This is the most important part of the entire undertaking, — the
right kind of a plan for the improvement of the grounds. The
person who calls the meeting should have a definite plan in mind ;
and this plan may be discussed and adopted. The remainder of
this bulletin is devoted to plans for school grounds and means of
working them out. If any person is interested in this subject, he
should have our Bulletin 121, on the " Planting of Shrubbery."

Begin with the fundamentals, not with the details. — If
an artist is to make a portrait, he first draws a few bold strokes,
representing the general outline. He ' ' blocks out ' ' the
picture. With the general plan well in mind, he gradually
works in the incidentals and the details, — the nose, eyes, beard.

Most persons reverse this natural order when they plant their
grounds. They first ask about the kinds of roses, the soil for
snowballs, how far apart hollyhocks shall be planted. It is as if
the artist first asked about the color of the eyes and the fashion
of the neck-tie ; or as if the architect first chose the color of
paint and then planned his building. The result of this type
of planting is that there is no plan, and the yard means nothing
when it is done. Begin with the plan, not with the plants.

The place should mean something. — The home ground
should be home-like, retired and cosy. The school ground
should be set off from the bare fields and should be open enough

HINTS ON RURAL SCHOOL GROUNDS.

279

to allow of play -grounds. It should be hollow, — well planted on
the sides, open in the interior. The side next the highway
should contain little planting. The place should be a picture, not a
mere collection of trees and bushes. Fig. 25 shows what I mean,
As seen in the picture (Fig. 25), this style of planting seems to
be too elaborate and expensive for any ordinary place. But if
the reader will bear with me, he shall learn otherwise.

25. — A picture, of which a schoolhouse is the central figure .

Keep the center of the place open* — Do not scatter the
trees over the place. They will be in the way. The boys will
break them down. Moreover, they do not look well when
scattered over the whole area. When an artist makes a picture
with many people in it, he does not place the persons one by one
all over his canvas. He masses them. Thereby he secures a
stronger effect. He focusses attention, rather than distributes it.

The diagrams (Figs. 26, 27), taken from Bulletin 121, make
this conception plain. The same trees and shrubs can be used
to make either a nursery or a picture. But it is more difficult to
make the nursery, and to keep it in order, because the trees
grow one at a place in the sod, and they are exposed to acci-
dents.

280

BULLETIN 160.

26. — The co)nmon or nursery type of planting.

Go to the blackboard. With four lines, represent the borders
of the school grounds, as in Fig. 28. Indicate the schoolhouse

and the out-
buildings. Ex-
isting trees may
be located by
small circles.
Now you have
the facts, or the
fixed points.

Now put in the
walks. The first
fixed point is the
front door. The
other fixed point
is the place or
places at which

the children enter the grounds. Join these points by the most
direct and simplest curves possible. That is all there is of it. In
many, or perhaps most places, the house is so near the highway
that only a straight walk is possible or advisable.

Next comes the
planting. Let it
be irregular and
natural, and rep-
resent it by a wavy
line, as in Fig. 28.
First of all, cover
upthe out-houses.
Then plant heav-
ily on the side
next the swamp
or a disagreeable
barnyard, or in ™—~ur m

the direction of 27. — The proper or pictorial type of planting.
the prevailing

wind. L/eave openings in your plan wherever there are views
to be had of fine old trees, attractive farm homes, a brook, or

HINTS ON RURAL SCHOOL GROUNDS.

281

28. — The blackboard plan.

a beautiful hill or field. Throw a handful of shrubs into the

corners by the steps, and about the bare corners of the building.
You now have a plan to work

to. It has been the work of five

minutes at the blackboard.
Sometimes the problem is not

so simple as all this. There may

be three entrances to the grounds

and a highway on two sides.

Fig. 29 is a plan made for such

a place in western New York.

It was thought to be necessary

to separate the play -grounds of

the boys and girls. This was done by a wide hedge-row of bushes

running back from the schoolhouse.

An interesting case as shown in Figs. 21 and 22. It is indecent

j I to put the two out-

buildings together.
But it was assumed
that it would not be
allowable to move
them. The place is
bald and cheerless .
The outlay of a day's
work, and no money,
might cause it to look
like Fig. 22 inside of
three or four years.

Perhaps some per-
sons object to so much

29. — Suggestions for the planting of a school- shrubbery. They look

yard upon four corners. From "Lessons

with Plants." uP°n lt: as mere brush.

Very well ; then use

trees alone. But do not scatter them hit and miss over the place.
Throw them in at the side, as in Fig. 30. Give room for
the children to play ; and make the place a picture at the same
time. Three or four trees may be planted near the building to
shade it, but the heaviest planting should be on the sides.

282

BULLETIN 160.

The mere planting of trees and shrubs is the smaller part of
the problem, — Arbor day has emphasized the mere planting of

trees. Fortunately,
many of the trees do
not live. They are
too often put in the
wrong places. If the

^f,^,,^^B,^^,^-, «..«_™, love of trees could be

m&

30. — A border planting of trees.

combined with some
purpose in the plant-
ing, the results would
be much better. Fig.
3 1 suggests Arbor Day
planting ; and this is
certainly much better
than nothing. These
four trees will be useful in their present positions, but the place
will still remain bare. The great thing — the border planting-
has been omitted, and the incidental thing has been done.

Observe how the long foliage-mass adds charm to Fig. 32. A
row is better than mere scattered trees. But even this planting-
is not ideal. Heavy planting should have been made along the
fence beyond the schoolhouse. There are too many trees between
the border row and the house, although this is not a serious
fault. A few bushes and vines would relieve the barrenness of
the house ; so would one or two trees close against the house on
the side next the road. But this place is so much more attrac-
tive than most rural school premises that one ought not to find
fault with it.

d. HOW TO MAKE THE IMPROVEMENTS.

Every effort should be exerted to do the work well in the begin-
ning. If all preparations are thoroughly considered, and the
details carried out with care, the premises should become more
attractive year by year with almost no annual outlay of labor.
The school grounds should be able to take care of themselves
when once the place is set in order. Of course, better results

HINTS ON RURAL SCHOOL GROUNDS.

283

are to be expected when much labor is put on the grounds each
year, but it is useless to advise such expenditure for the rural

31. — Trees enough in the center, but the place needs a back-ground.

32. — A row of willows makes the place attractive.

schools. But it is surprising what excellent results can be
secured with almost no attention from year to year. The beau-

284 BULLETIN 160.

tiful garden in Fig. 34 has received practically no labor for three
years except that required to mow the grass.

Making the sod. — In mail}' cases the school yard is already
level or well graded and has a good sod, and it is not nec-
essary to plow it and re-seed it. It should be said that the sod
on old lawns can be renewed without plowing it up. In the
bare or thin places, scratch up the ground with an iron-toothed
rake, apply a little fertilizer, and sow more seed. Weedy lawns
are those in which the sod is poor. It may be necessary to pull
out the weeds ; but after they are out, the land should be quickly
covered with sod or they will come in again. Annual weeds,
as pigweeds, ragweed, can usually be crowded out by merely
securing a heavier sod. A little clover seed will often be a good
addition, for it supplies nitrogen and has an excellent mechanical
effect on the soil.

The ideal time to prepare the land is in the fall, before the
heavy rains come. Then sow in the fall, and again in early
spring on a late snow. However, the work may be done in
spring, but the danger is that it will be put off so long that the
young grass will not become established before the dry hot
weather comes.

The only outlay of money required for the entire improvement
is for grass seed. The best lawn grass for New York is June-
grass or blue-grass. Seedsmen know it as Poa pratensis. It
weighs but 14 pounds to the bushel. Not less than three bush-
els should be sown to the acre. We want many very small stems
of grass, not a few large ones : for we are making a lawn, not a
meadow.

Do not sow grain with the grass seed. The June-grass grows
slowly at first, however, and therefore it is a good plan to sow
timothy with it, at the rate of two or three quarts to the acre.
The timothy comes up quickly and makes a green ; and the
June-grass will crowd it out in a year or two. If the land is hard
and inclined to be too dry, some kind of clover will greatly assist
the June-grass. Red clover is too large and coarse for the lawn.
Crimson clover is excellent, for it is an annual, and it does not
become unsightly in the lawn. White clover is perhaps best,
since it not only helps the grass but looks well in the sod. One
or two pounds of seed is generally sufficient for an acre.

HINTS ON RURAL SCHOOL GROUNDS. 285

At first the weeds will come up. Do not pull them. Mow the
lawn as soon as there is any growth large enough to mow. Of
course, the lawn mower is best, but there is no use of recommend-
ing it for rural school yards. Then use the ordinary field
mower. When the sod is established, mowing the yard three or
four times a year will be sufficient. And here is another advant-
age of the open-centered yard which I have recommended, -
it is easily mown. It would be a fussy matter to mow a yard
planted after the fashion of Fig. 26 ; but one like Fig. 27, is
easily managed. A yard like Fig. 25 can be mown in a half hour.

How to make the border planting. — The borders should
be planted thick. Plow up the strip. Never plant these trees
and bushes in holes cut in the sod. Scatter the bushes and
trees promiscuously in the narrow border. In home grounds, it is
easy to run through these borders occasionally with a cultivator,
for the first year or two.

Make the edges of this border irregular. Plant the lowest
bushes on the inner edge. Fig. 33 shows how a certain yard was
marked out for the planting. The wThole area had been plowed,
rolled, harrowed and raked. Grass seed had been sown and raked
in. Then a line was drawn, by means of a rake handle, to represent
the edges of the border planting. The interior or lawn space
was now rolled, and th,e soft area along the borders was left for
the planting. Five years later, the place looked as shown in
Fig. 34. Imagine a schoolhouse at the end of that garden !

For all such things as lilacs, mock-oranges, Japan quinces, and
bushes that are found along the roadsides, two or three feet apart
is about right. Some will die anyway. Cut them back one-half
when they are planted. They will look thin and stiff for two or
three years; but after that they will crowd the spaces full, lop over
on the sod, and make a billow of green. Prepare the land well,
plant carefully ; andlet the bushes alone.

The kinds of plants for the main planting.— We now come to
the details, — the particular kinds of plants to use. One great
principle will simplify the matter : the • main planting should
be for foliage effects. That is, think first of giving the place
a heavy bordermass. Flowers are mere decorations.

Select those trees and shrubs which are the commonest, because

286

BULLETIN 160.

they are cheapest, hardiest and most likely to grow. There is no
district so poor and bare that enough plants cannot be secured,
without money, for the school yard. You will find them in
the woods, in old yards, along the fences. It is little matter
if no one knows their names. What is handsomer than a
tangled fence -row ?

Scatter in a few trees along the fence and about the buildings.

33. — A newly made landscape garden, ready for the border planting .

Maples, basswood, elms, ashes, buttonwood, pepperidge, oaks,
beeches, birches, hickories, poplars, a few trees of pine or spruce
or hemlock, — any of these are excellent. If the country is bleak, a
rather heavy planting of evergreens about the border, in the
place of so much shrubbery, is excellent.

For shrubs, use the common things to be found in the woods
and swales, together with roots which can be had in every old
yard. Willows, osiers, witch hazel, dogwood, wild roses, thorn
apples, haws, elders, sumac, wild honeysuckles, — these and
others can be found in every school district. From the farm
yards can be secured snowballs, spireas, lilacs, forsythias, mock-

288

BULLETIN 160.

-

oranges, roses, snowberries,
barberries, flowering cur-
rants, honeysuckles and
the like.

Vines can be used to ex-
cellent purpose on the out-
buildings or on the school-
house itself. The com-
mon wild Virginia creeper
(shown on the right in Fig.
36) is the most serviceable.
On brick or stone school
houses the Boston ivy or
Japanese ampelopsis may be
used, unless the lo-

35. — It is easy to make*ayard as good as this, cation is very bleak.
This is not hardy in the northern parts of the State.
Honeysuckles, clematis and bitter-sweet are also attrac-
tive. Bowers are always interesting to children ; and
actinidia (to be had at nurseries) is best for this
purpose.

Kinds of plants for decoration.—

Against these heavy borders and in the
angles about the building, many kinds
of flowering plants can be grown.
The flowers are much more easily
cared for in such positions than
they are in the middle of the lawn,
and they also show off better. Notice
how striking the holyhocks are in
Figs. 34 and 37. They have a back-
ground. Even a clump of weeds looks
well when it is in the right place.
Observe Fig. 36.

It is impossible to grow many flowers
in the school ground under present con-
ditions, for what is everybody's busi- creeper. How pretty they are !
ness is nobody's business ; and then, the place is neglected all through

HINTS ON RURAL SCHOOL GROUNDS. 289

the summer. But the children can be taught to plant many
things.

Only those flowers should be used which are very
easy to grow and which have the habit of taking
care of themselves. They should also be such as
bloom in spring or fall, when the school is in ses-
sion. Perennial plants — those which live from year
to year — are excellent. Of these, day lilies, bleed-
ing hearts, pinks, bluebells, hollyhocks, perennial
phlox and hibiscus, are always useful. Nothing
is better than the common wild asters and golden-
rods. They will grow almost anywhere and they
improve when grown in rich ground and given ZI. —
plenty of room ; and they bloom in the fall.

Many kinds of bulbs are useful, especially as so many of them
bloom very early in spring. We propose to issue^a nature-study
leaflet on this subject the coming season. Think of a school
yard with crocuses, daffodills and tulips in it \

Annual flowers may be grown along the borders, out of the
way of the play-grounds. China asters, petunias and Cali-
fornia poppies are very attractive, and they are easy to grow.
They bloom in the fall. Phlox, swreet peas, allyssum, and
many others are also useful. Consult Bulletin 161.

While the main planting should be made up of common trees
and shrubs, a rare or strange plant may be introduced now and
then from the nurseries, if there is any money with which to buy
such things. Plant it at some conspicuous point just in front
of the border, where it will show oil well, be out of the way,
and have some relation to the rest of the planting. Two or
three purple-leaved or variegated-leaved bushes will add much
spirit and verve to the place ; but many of them make the place
look fussy and overdone.

e. GENERAL REMARKS.

More than one-third of all public schools will probably always
be in the country. They will have most intimate relations with
rural life. We must make that life attractive to the pupils.

In Europe there are school gardens, and similar plans are

290 BULLETIN 160.

recommended for this country. It is certainly desirable that
some area be set aside for the actual cultivation of plants by the
children and for the growing of specimens to be used in the
school room. However, the conditions of Europe are very
different from ours. In the rural school in Germany and other
countries, the school house is the teacher's home. He lives in it,
or by it. The summer vacation is short. In this country, there
is no one to care for the rural school ground in the long summer
vacation. Teachers change frequently. It is impossible to have
uniformity and continuity of purpose. In the Old World, the
rural schools are in the hamlets.

We shall be very glad to correspond with any persons who are
interested in improving school premises, either on the lines
herein suggested, or in other directions. The improvement must
come, or, one by one, the rural schools will die out .for lack of
pupils. In the struggle for existence, the pupils will more and
more seek the more attractive schools. There must be rural
schools, whether in the open country or in the hamlet ; and
wherever they are, they must be cheered and brightened.

A Flower Day every October would be a fitting complement of
Arbor Day. Already, flower shows have been held in various
rural schools. They are symbols of the harvest. We want to
focali/e this movement in the coming year. We call upon ever)7
citi/en for sympathy and cooperation.

A revolution in rural school grounds will not come suddenly.
Here and there a beginning will be made ; and slowly the great
work will spread. L. H. BAILEY.

Bulletin 168. May, 1899.

Cornell University Agricultural Experiment Station,

ITHACA, N. Y.

BOTANICAL DIVISION:

Studies and Illustrations

OF —

MUSHROOMS: II.

" By the rose flesh mushrooms, undivulged
Last evening. Nay, in to-day' s first dew
Yon sudden coral nipple bulged,
Where a freaked, fawn-colored, flaky crew
Of toadstools peep indulged.''1

Browning's By the Fireside.

THREE EDIBLE SPECIES OF COPRINUS.
By GEO. F. ATKINSON.

PUBLISHED BY THE UNIVERSITY,

ITHACA, N. Y.

I899.

ORGANIZATION.

BOARD OF CONTROL :
THE TRUSTEES OF THE UNIVERSITY

THE AGRICULTURAL COLLEGE AND STATION COUNCIL.

JACOB GOULD SCHURMAN, President of the University.

FRANKLIN C. CORNELL, Trustee of the University.

ISAAC P. ROBERTS, Director of the College and Experiment Station.

EMMONS L. WILLIAMS, Treasurer of the University.

LIBERTY H. BAILEY, Professor of Horticulture.

JOHN H. COMSTOCK, Professor of Entomology.

STATION AND UNIVERSITY EXTENSION STAFF.

I. P. ROBERTS, Agriculture.

G. C. CALDWELL, Chemistry.

JAMES LAW, Veterinary Science.

J. H. COMSTOCK, Entomology.

L. H. BAILEY, Horticulture.

H. H. WING, Dairy Husbandry.

GEO. F. ATKINSON, Botany.

M. V. SLINGERLAND, Entomology.

G. W. CAVANAUGH, Chemistry.

L. A. CLINTON, Agriculture.

W. A. MURRILL, Botany.

J. W. SPENCER, Extension Work.

J. L. STONE, Sugar Beet Investigation

MISS M. F. ROGERS, Nature-Study.

A. L. KNISELY, Chemistry.

C. E. HUNN. Horticulture.

G. W. TAILBY, Foreman of the Farm.

A. R. WARD, Dairy Bacteriology.

L. ANDERSON, Dairy Husbandry.

OFFICERS OF THE STATION

I. P. ROBERTS, Director.
E. L. WILLIAMS, Treasurer.
EDWARD A. BUTLER, Clerk.

Office of Director, Room 20, Morrill Hall.

CORNELL UNIVERSITY, ITHACA, May 15, 1899.
HONORABLE COMMISSIONER OF AGRICULTURE, ALBANY, N. Y.

Sir: This bulletin, the second of a series of "Studies and
Illustrations of Mushrooms," is submitted under Chapter 67 of
the Laws of 1898. The object of these studies is to give accu-
rate information upon, and illustrations of, the more common
mushrooms or toad-stools. This should enable interested per-
sons to collect and determine specimens occurring from spring to
late autumn. Large numbers of the edible species go to waste
each year for the want of some clear and ready information to
assist in distinguishing the edible from the poisonous kinds.

It is to be regretted that in the smaller cities, in suburban
districts, and upon the farms, more attention is not given to
learning to know well a few of the more common species, since
the fields and woods where these plants grow are so easy of
access. By careful attention to the localities and by comparison
of the plants with the descriptions and illustrations given in
these bulletins, a person having no botanical knowledge can
identify a number of these plants. Every one has, or should
have, a certain amount of leisure time which can be devoted to
recreation, or relief from the every day work. Many find enjoy-
ment and profit in combining such recreation with an interest in
some observation upon nature and natural objects. Having
learned to recognize the edible species, it is possible thereafter to
readily collect for food large numbers of the more common ones.
Some of these plants are so easily determined that children only
eight years old, after seeing the photographs of two of the
species illustrated in this bulletin, were able later to name the
plants from freshly collected specimens, without the opportunity
of a comparison with the photographs.

One not familiar with the subject should use caution in the
first collections of an unknown plant. It is well in some cases

492 BULLETIN 168.

to consult some one who does know the plants, or who has the
means of determining them. In such cases, the Botanical
Division of this Station is ready to assist in the identification.
Directions for collecting and mailing specimens are given in the
present bulletin. With some attention to this subject there is no
reason why, in America, mushrooms should not form as important
an article of food as they do in parts of the Old World.

Professor Atkinson has made a large number of photographs
of the edible and poisonous mushrooms, as well as of those wood
destroying species so destructive to timber and forest trees.

I. P. ROBERTS, Director.

STUDIES AND ILLUSTRATIONS OF MUSH-
ROOMS, II.

Three Edible Species of Coprinus.
I — THK SHAGGY-MANE (Coprinus contains] .

The "shaggy-mane," or "horsetail mushroom" (Coprinus
comatus) , is one of the largest plants of this genus. It is usually
considered by many to surpass all the other species of the genus
in those qualities most esteemed by the fungus eater. The
frontispiece is from a photograph of a group of these plants
growing in a lawn on the Cornell University Campus. All stages
of the "horsetail" are here represented, from the tiny ones
which are thrusting their heads through the turf to the old ones
which present an unsightly aspect as they are melting down
into inky blackness, an example of the swiftness with which it
passes its ephemeral existence. A day, or at most two or three
days is vouchsafed to it during which it is to lift itself up into
the free air, where it may expand and mature its spores. Then
it vanishes. But it has accomplished the final purpose for which
it exists as an organism. Its "seed," the spores are free to
be carried by the wind or other agencies of dissemination to
distant places, and thus propagate the species. While the
natural mode of the wide dissemination of the plant is probably
by the distribution of the spores, dissemination may take place
through the agency of man or other animals when the soil is
disturbed.

Some of the ' ' spawn ' ' may be transplanted in the sod for
covering new lawns, or in the fertilizer for old ones. Here food
lying hidden in the soil is awaiting forage at the pleasure of the
searching threads of the mycelium or "spawn," which now
spreads its meshes as it extends through the earth. Here it
grows for months or sometimes for years may be, laying b}7 sup-
plies in the shape of an increased amount of "spawn." We
tread upon the soft carpet of green or recline on the sod unmind-

494

BULLETIN 168.

(34)

ful of the process of growth, absorption and assimilation in that
wonderful unseen world of plant life. Suddenly some morning we
see the shaggy, unkempt heads of our old friends again just risen
from their long sleep which calls to mind Browning's verse,—

' ' By the rose flesh mushrooms undivulged

L/ast evening. Nay, in to-day's first dew
Yon sudden coral nipple bulged,

Where a freaked, fawn-colored flaky crew
Of toad-stools peep indulged. ' '

83. — "Shaggy-mane" (Coprinus contains} in lawn.

A " mushroom growth," we say. It looks that way ; as if the
whole thing had grown in a single night. That is because we
have not searched underneath the sod and observed the long,
tedious process of growth while the cords and meshes of the
mycelium have increased, and extended their lines through the
moist soil. If we do search there and observe we see that some-
time before the shaggy heads peep forth, tiny bodies appear on
the cords of mycelium ; first like a pin head in size, then as large
as a pea and the size of a thimble they grow. A great deal of

(35) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 495

growth has taken place in the formation of these tiny bodies
beneath the soil. They are made up of delicate threads and the
tiniest cells which have multiplied until there are countless num-
bers of them. Now when every thing is ready in these fungus
"buttons," the tiny cells already formed, as well as new ones still
forming, expand rapidly and this pushes the mushroom up into
view in a single night.

In figure 84 are shown two buttons of the size when they are
just ready to break through the soil. They are now quite dark

84. — " Buttons'1'1 of Coprinus ; two in section, showing gill slits and
hollow stem. (Natural size. )

in color on the outside. They appear mottled with dark and
white, for the outer layer of fungus threads, which are dark
brown, is torn and separated into patches or scales, showing
between, the delicate meshes of white threads which lie beneath.
The upper part of the button is already forming the cap or
"pileus," and the slight constriction about midway shows the
lower boundary or margin of the pileus where it is still connected
with the undeveloped stem.

We are curious to know if the internal structure of these but-
tons will reveal the parts of the mushroom. We can learn this
by splitting buttons through from one end to the other with a

496 BULLETIN 168. (36)

sharp knife. At the right of each of these buttons in the figure
is shown a section of a plant of the same age. Here the parts of
the plant though still undeveloped are quite well marked out.
Just underneath the pileus layer are the gills. In the section

85. — Coprinus comatus, removed from soil. (Natural size.}

one gill is exposed to view on either side. They are long, narrow,
and taper at each end. In the section of the larger button the
free edge of the gill is still closely applied to the stem, while in

(37) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 497

the small one the gills are separated a short distance from the

stems showing "gill slits."

Here, too, the connection of the

margin of the pileus with the stem

is still shown. From our first

study of mushrooms (Bulletin

1 38) we know that this connecting

layer between the margin of the

pileus and stem forms the veil.

This kind of a veil is a marginal

veil.

The stem is hollow even at this
young stage, and a slender cord
of mycelium extends down the
center of the tube thus formed as
is shown in the sections. From
the button stage the growth is
quite rapid, and in a short while
the plants are full grown.

Now the plants are nearly all
white. The brown scales so close
together on the buttons are widely
separated except at the top or
center of the pileus, where they
remain close together and form a
broad cap resting jauntily on the
shaggy head. This is shown in
figure 85 which is from a photo-
graph of three plants removed
from the sod.

A study of the different stages,
which appear from the button
stage to the mature plant, reveals
the cause of this change in color
and the wide separation of the
dark brown scales. The threads
of the outer layer of the pileus,
and especially those in the brown
patches seen on the buttons, soon

86. — Coprinus comatus, well mer-
iting the name "shaggy mane".

(Natural size.)

498

BULLETIN 168.

(38)

cease to grow, though they are firmly entangled with the inner
layers. Now the threads underneath and all through the plant,
in the gills and in the upper part of the stem grow and elongate
rapidly. This pulls on the outer layer tearing it in the first place
into small patches and causing them later to be more widely

separated on the mature
plant. Some of these
scales remain quite large
while others are torn up in-
to quite small tufts.

As the plant ages, the
next inner layers of the
pileus grow less rapidly, so
that the white layer beneath
the brown is torn up into an
intricate tangle of locks and
tufts, or is frazzled into a
delicate pile which exists
here and there between well
formed tufts. While all
present the same general
characters there is consider-
able individual variation as
one can see by comparing a
number of different plants.
Figure 86 shows one of the
interesting conditions.
There is little of the brown
color, and the outer portion
of the pileus is torn into
^.—Coprinus comatus, surface of pileus long locks, quite evenly dis-
gatheredin loups. (Natural size}. tributed and curled up at

the ends in an interesting fashion which merits well the term
"shaggy." In others the threads are looped up quite regularly
into triangular tresses which appear to be knotted at the ends
where the tangle of brown threads holds them together as if
some fairy had plaited the lock.

There is one curious feature about the expansion of the pileus

(39) STUDIES AND ILLUSTRATIONS OF MUSHROOMS: II. 499

of the shaggy-mane which could not escape our attention. The
pileus has become very long while comparatively little lateral

88. — Coprinus comatus, sections of the three plants shoiun in figure 85.

(Natural size}.

expansion has taken place. The pileus has remained cylindrical
or barrel-shaped, while in the case of the mushrooms treated of in
our first study the pileus expanded into the form of an umbrella.

500

BULLETIN 168.

(40)

The cylindrical or barrel-shaped pileus is characteristic of the shag-
gy-mane mush-
room. As the
pileus elongates
the stem does
also, but more
rapidly. This
tears apart the
connection of the
margin of the
pileus with the
base of the stem,
as is plainly
shown in figure
85. In breaking
away, the con-
necting portion
or veil, is freed
both from the
stem and from
the margin o f
the pileus, and
is left as a free,
o r loose ring,
around the stem.
In all of the
plants of our for-
mer study, the
common mush-
room (Agaricus
campestris) , the
smooth lepiota
(Lfpiota nauci-
na) , and the
deadly amanita
(Amanitap hallo-
ides) , the ring

remained attached to the stem, i. e., it is not a free ring in those

89. — Coprinus comatus, early stage of diliquescence.
The ring is lying on the sod. (Natuial size.}

(41) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 501

species. In the shaggy-mane the veil does not form a thin
expanded curtain as in the three species just enumerated. It
is really an annular outer layer of the button lying between the

margin of the
base of the stem,
from the stem,
gates more rap-
pileus, the latter
u p away r
base of the
Sometimes
the free

pileus and the
It becomes free
As the stem elon-
idly than the
is lifted
from the
K\ stem.

annulus is left as a
of the stem, still
superficial 1 a yer of
for a time more or
margin o f the pileus
at the left hand in
lifted higher up on
comes free from the
dangling somewhere
break and fall down
instances it may re-
herent to the margin
breaks apart as the
somewhat. In such
for some time to dis-
sterile margin of the
its outer texture re-
ure of the pileus.

90. — Coprinus com

ing more expanded.
(Natural size).

collar around the base
loosely adherent to the
the same, or it remains
less adherent to the
as shown in the plant
figure 85. It is often
the stem before it be-
pileus, and is then left
on the stem, or it may
on the sod. In other
main quite firmly ad-
of the pileus so that it
pileus in age expands
cases one of ten searches
cover it clinging as a
• pileus, so closely does
semble the outer text-
It is interesting to ob-

serve a section of the plants at this stage. These sections can be
made by splitting the pileus and stem lengthwise through the
middle line with a sharp knife as shown in figure 88. Here, in

502

BULLETIN 168.

(42)

the plant at the right hand, the "cord" of mycelium is plainly
seen running through the hollow stem. This cord is well seen

91. — Coprinns contains, drops of inky fluid about to fall from wasted pileus.

(Nutural size}.

(43) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 503

if one partly splits a stem and then gently pulls the halves apart.
At the same time if the stem is held toward the light a very deli-
cate mesh of threads, reminding one of the finest gauze, is seer-
extending from the cord to the wall of the tubular stem. The
gills form a large portion of the plant for they are very broad and
lie closely packed side by side. They are nowhere attached to
the stem but at the upper end round off to the pileus leaving a
well defined space between their ends and the stem. The pileus,
while it is rather thick at the center, i. e., where it joins the stem,
becomes comparatively thin where it spreads out over the gills.
At this age of the plant the gills are of a rich salmon color, i. <?.,
before the spores are ripe, and the taste when raw is a pleasant
nutty flavor reminding one of the meat of fresh green hickory
nuts. In a somewhat earlier stage the edges of all the gills are
closely applied to the stem which they surround. So closely are
they applied to the stem in most cases that threads of
mycelium pass from the stem to the edge of the gills, so that
they might be said to be "sewed" together. As the- pileus
expands slightly in ageing, these threads are torn asunder and
the stem is covered with a very delicate down or with flocculent
particles which easily disappear on handling or by the washing
of the rains. The edges of the gills are also left in a frazzled
condition as one can see by examining them with a good hand
lens.

The spores now begin to ripen and as they become black the
color of the gills changes. At the same time the gills and the
pileus begin to dissolve into an inky fluid, first becoming dark and
then melting into a black liquid. As this accumulates it forms
into drops which dangle from the pileus until they fall away. This
change takes place on the margin of the pileus first, and advances
toward the center, and the contrast of color, as the blackening
invades the rich salmon, is very striking. The pileus now begins
to expand outward more, so that it becomes somewhat umbrella
shaped. The extreme outer surface of the pileus does not dili-
quesce so freely, and the thin remnant curls upward and becomes
enrolled on the upper side as the pileus with wasted gills becomes
nearly flat.

504

BULLETIN 168.

(44)

\

(45) STUDIES AND ILLUSTRATIONS OF MUSHROOMS: II. 505

II. — THE INK-CAP (Coprinus atramentarius).

The ink-cap (Coprinus atramentarius) occurs under much the

same conditions as the shaggy -mane, and is sometimes found

accompanying it. It is usually more common and more abundant.

It springs up in old or newly made lawns which have been richly

93. — Coprinus atramentarius, scaly form. {Natural size '.)

manured, or it occurs in other grassy places. Sometimes the
plants are scattered, sometimes two or three in a cluster, but
usually large clusters are formed where ten to twenty or more
are crowded closely together (figure 92). The stems are shorter
than those of the shaggy-mane and the pileus is of a different
shape and color. The pileus is more egg-shaped or oval. It

506

BULLETIN 168.

(46)

varies in color from a silvery grey in a few forms, to a dark ashen
grey, or smoky brown color in others. Sometimes the pileus is
entirely smooth, as I have seen it in some of the silvery grey

94. — Coprinus atramentarius ; showing annulus as a border line between
scaly and smooth part of stem. (Natural size.}

forms, where the delicate fibres coursing down in lines on the
outer surface cast a beautiful silvery sheen in the light. Other
forms present numerous small scales on the top or center of the
pileus which are formed by the cleavage of the outer surface here
into large numbers of pointed tufts. In others, the delicate
tufts cover more or less the entire surface, giving the plant a
coarsely granular aspect. This is perhaps the more common
appearance, at least so far as my observation goes. But not
infrequently one finds forms which have the entire outer surface

(47) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 507

of the pileus torn into quite a large number of coarse scales, and
these are often more prominent over the upper portion. Fine
lines or striations mark also the surface of all the forms,
especially toward the margin where the scales are not so promi-

95. — Coprinus atramentar inspection plant. (Natural size.}

nent. The marginal half of the pileus is also frequently furrowed
more or less irregularly, and this forms a crenate or uneven edge.
The annulus or ring on the stem of the ink-cap is very
different from that of the shaggy-mane. It forms an irregularly
zigzag elevated line of threads which extend around the stem
near the base. It is well shown in figure 94 as a border line

508

BULLETIN 168.

(48)

between the lower scaly end of the stem and the smooth white
upper part. It is formed at the time of the separation of the
margin of the pileus from the stem, the connecting fibres being
pulled outward and left to mark the line of junction, while
others below give the scaly appearance. It is easily effaced by
rough handling or by the washing of the rains. A section of
a plant is illustrated by a photograph in figure 95. On either
side of the stem is shown the layer of fibres which form the
annulus, and this layer is of a different texture from that of the
stem. The stem is hollow as seen here also. In this figure one
can see the change in color of the gills just at the time when
they begin to diliquesce. This diliquescence proceeds much in
the same way as in the shaggy-mane, and sometimes the thin
remnant of the pileus expands and the margin is inrolled over
the top.

III. — THE GLISTENING COPRINUS (Coprinus micaceus).

The third species described here is the glistening coprinus

(Coprinus micaceus]. It received this name because of the very

delicate scales which often cover the surface of the pileus, and

glisten in the light like particles of mica. This plant is very

common during the spring
and early summer though it
does appear during the au-
tumn. It occurs about the
bases of stumps or trees or in
grassy or denuded places,
from dead roots, etc., buried
in the soil. It occurs in dense
tufts of ten to thirty or more
individuals ; sometimes as
many as several hundred
spring up from the roots of a
dead tree or stump along the
streets or in lawns, forming
large masses More rarely
it occurs on logs in the woods,
and sometimes, the plants are

96. — The "glistening coprinus,'"
Coprinus micaceus; young stage
showing annulus, on the pileus
the " mica" particles. {Natural
size. )

scattered in lawns. From the different habits of the plant it

(49) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 509

is sometimes difficult to determine, especially where the
individuals are more or less scattered. However, the color of
the plant, and the markings on the pileus, especially the presence
of the small shining scales when not effaced, characterize the
plant so that little difficulty is experienced in determining it
when one has once carefully noted these peculiarities.

micaceus, showing different aspects.
(2-3 natural size. )

Figure 96 is from a group of three young individuals photo-
graphed just as the margin of the pileus is breaking away from
the lower part of the stem, showing the delicate fibrous ring
which is formed in the same way as in Coprinus atramentarius.
The ring is much more delicate and is rarely seen except
in very young specimens which are carefully collected and which

510 BULLETIN 168. (50)

have not been washed by rains. The mature plants are 8 cm.
to 10 cm. high (3-4 inches), and the pileus varies from 2 cm.
to 4 cm. in diameter. The stem is quite slender and the pileus
and gills quite thin as compared with the shaggy-mane and ink-
cap. The gills are not nearly so crowded as they are in the two
other species. The pileus is tan color, or light buff , or yellow-
ish brown. Except near the center it is marked with quite
prominent striations which radiate to the margin. These stria-
tions are minute furrows or depressed lines, and form one of the
characters of the species, being much more prominent than on
the pileus of the ink-cap.

In wet weather this coprinus melts down into an inky fluid
also, but in quite dry weather it remains more or less firm, and
sometimes it does not diliquesce at all, but dries with all parts
well preserved though much shrunken of course as is the case
with all the very fleshy fungi.

Many persons who are fond of mushrooms do not venture to
collect and eat other species then the Agaricus campestris. Many
will tramp considerable distances to collect the ' ' pink gilled
agaric," and pass by on the street, or perhaps in their dooryard,
a clump of coprinus sufficient for a meal. During the spring and
early summer the Agaricus campestris is not to be had in the
open, while these three species of coprinus usually grow in
abundance, though the shaggy-mane is usually more abundant
in the autumn than in the spring.

During the autumn of 1898 the common " pink gilled mush-
room " {Agaricus campestris] was very rare in the vicinity of
Ithaca. This has led a few to search for other forms. Two of
my friends during October brought into my office a peck basket
filled with mushrooms, and wished to know if they were "good to
eat." Nearly all of the plants were the "ink-cap " (C. atramen-
tarius], there were four or five of the shaggy-mane (C. comatus),
and a single " glistening coprinus " (C. micaceus). All of them
good to eat and collected in a single dooryard. One of these
gentlemen had never before ventured to partake of any other
species than the Agaricus campestris.

During the early summer of 1897, while collecting a " mess "

(51) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 511

of Coprinus micaceus from a large tuft growing around the base
of a stump on one of the principal streets of Ithaca, a passer-by
halted, probably for the charitable purpose of giving some infor-
mation which he thought might save my life. " Them's toad-
stools ain't they? " " Yes," I replied. " Well, I thought so,"
said he. Thereupon I ate one of the "toad-stools" raw, and
received from him a look of mingled pity and despair as he
passed on.

All of these three species have a somewhat nutty flavor, that
of fresh hickory nuts when eaten raw, but they are more palata-
ble when properly prepared for the table. The Coprinus mica-
ceus need only be rinsed to remove from the caps any adhering
particles of soil. The other two species may be peeled if it is
desired to remove the outer and tougher layer of the pileus, or
this may be done by gently scraping. The shaggy-mane peels
well by starting at the margin of the pileus and with the fingers
stripping off the outer layer. The ink-cap peels more readily by
first splitting the pileus in halves and then starting the strip at
the top of each half. It is sufficient, however, to gently scrape
the surface of the pileus to remove the coarser outer fibers and
whatever soil may adhere.

To those who are not acquainted with any of the species of
coprinus and wish to extend the range of species collected for
table use these three species are commended. The shaggy-mane
is perhaps the most delicious of the three, but the other two are
much more abundant usually. By a careful comparison of the
species growing in lawns, and along streets with these descrip-
tions, and especially with the illustrations, there should be no
trouble in identifying them. While the camera here has not at
present succeeded in reproducing all the colors, this series of pho-
tographs illustrates well the habit, texture and specific characters
of the plants, and the color values in black and white are quite
faithfully represented. It is doubtful if any hand coloring has
yet succeeded in producing such perfect imitations as these pho-
tographic studies of the shaggy- mane and ink-cap. That they
accurately portray the habit and specific characters of these plants
I am convinced by the experience of my little boy of eight years.
While selecting the illustrations for this study one evening, I

512 BULLETIN 168. (52)

showed him the photographs, told him the names of each and the
parts of the mushroom. The subject was not mentioned again
until a week later when I brought in a few specimens of one of
the species. "What is the name of this?" I said. "That's
the shaggy-mane," he said. "What partis this?" "That's
the cap." "And this?" That's the ring." "And this?"
That's the stem." " Now, father," he said, " where 's the ink-
cap? " At another time he was able to select the ink -cap from
among a miscellaneous collection.

While the Coprinas micaceus usually grows on decaying wood,
or roots, etc., underneath the soil, the shaggy-mane and ink-cap
grow in rich soil in grassy places, especially such as have been
quite recently manured. This latter peculiarity of growing on
manured ground, or on dung, so characteristic of a number of
the species of the genus, suggested the name " coprinus, " from
the work " kopros" meaning dung.

A large number of the species of the genus,, practically all the
large fleshy ones (some of the smaller also) diliquesce into an
inky fluid. In the delicate or membranous ones, usually quite
small species, the pileus splits in radiating lines above each gill
in such a way that the gill itself is split downward, thus giving
to the pileus a fluted appearance.

In bulletin 138 the writer suggested the formation of mycolog-
ical clubs as a medium for the exchange of information among
interested persons in a given community. At that time there
was already in existence among others, the Boston Mycological
Club, New York Mycological Club and the Philadelphia Mycolog-
ical Center. Since that time there have been organized the
Washington Mycological Club, Chicago Mycological Club, and
others.

CORNELL MYCOLOGICAL CLUB.

A mycological club has recently been organized at Cornell Uni-
versity, with a somewhat broader work in view. It is called the
' ' Cornell Mycological Club ' ' and is under the supervision of the
members in the Botanical Department. Its purpose is to study
the fungi, to propagate information concerning them among its
members, and to encourage the growing popular interest in those

(53) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 513

groups of economic importance, to which belong especially the
edible, poisonous and parasitic fungi.

The rules governing the club are such that they admit to
membership any person interested in its aims and work. No
other qualifications except the payment of the small annual fee
of twenty-five cents, are necessary, and any person sending name
and enclosing the fee will be placed on the membership roll.
This small fee is to be used in necessary expenses incurred relat-
ing to executive matters of the club, as determined by the
Executive Council. With this small fee it will not be possible
at present to publish a bulletin of information. It is hoped,
however, that it will lead eventually to some medium of com-
munication among members, by which a knowledge of the
numerous local fungus floras may be obtained, and that this
information as well as other matters of interest may be regularly
communicated to members.

It is purposed to make the club a center to which persons inter-
ested in the study, and in becoming acquainted with the fungi,
may appeal for aid in the determination of species they collect.
To this end a few general directions are given here for those who
desire to know how to put up specimens properly for mailing, so
that they will not be broken or ruined in transit.

How TO MAIL FLESHY FUNGI.

Fresh " mushrooms," or " toad-stools" if of medium or large
size, should be wrapped separately in tissue paper, or if the plants
grow in tufts the paper can be worked in between the individual
specimens unless the tuft is a compact one. A sufficient amount
of paper should be used to give support to the expanded parts
of the plant, and so arranged that delicate structures on the sur-
face will not be rubbed away. The plants should then be packed
quite firmly, but not crushed, into a tin box, or a light but
strong wooden box. If they do not quite fill it more paper can
be added, so that they will not jostle about, or they become
badly broken. Pasteboard boxes are apt to become broken and
ruin the specimens.

In collecting the mushrooms do not break off the stems, but
pry the stems out of the earth carefully in order to preserve all

514 BULLETIN 168. (54)

the characters on the lower end of the stem. Also use care in
handling the stems so that the "collar," when present, and the
delicate scales, be not rubbed off. The corky or woody fungi
growing on trees, logs, stumps, etc., may be wrapped in the
same way. In all specimens from logs or trees, the name of the
wood should be given when that is accurately known. When
the name of the tree is not known a portion of the wood and
bark, or some leaves, nay accompany the specimen. The corky
or woody fungi may be dried before mailing if desired. To dry
the fleshy fungi requires considerable care, and usually artificial
heat, for they must be dried quickly, not burned or roasted,
though careful notes upon the characters of the plants while fresh,
should also be made before they are dried, in most cases.

An extemporized oven for drying may be made of tin, with
holes in the sides for ventilation. In this the plants can be
placed in paper boxes while they are drying. The oven may
then be placed above a stove, or a lamp may be placed under-
neath it. Shelves above a stove where warm air is constantly
rising is a good place to dry the plants. The best place that I
have ever used is the brick work around a large steam boiler,
the plants, or boxes containing them, being placed directly on the
brick work. Parasitic fungi on leaves of plants should be dried
between absorbent paper under some pressure to keep the leaves
from shriveling and curling.

Dried specimens of the mushrooms can be wrapped in tissue
paper for shipment. It is better in most cases, however, if the
plants are shipped away for determination, to send them in a
fresh condition. At least some duplicates are desirable in a fresh
condition, since fresh material is often necessary for determina-
tion of the species, especially with doubtful species, and in the
case of many genera.

When fresh material is mailed, if the sender will use foresight
in putting it up and mailing just in time for a mail train which
makes good connections through, specimens will usually travel
several hundred miles and arrive in a good condition.

Specimens sent by mail require, according to the present
postal regulations, i ct. per 2 ounces in weight, and the
package should be marked " plants." Wherever it is desired to

(55) STUDIES AND ILLUSTRATIONS OF MUSHROOMS : II. 515

send by express, the sender should pay the express charges,
except where good material prepared and named for the her-
barium or museum is contributed, or where the sender is certain
that the material is of value, as in the case of some rare
specimens. In all cases where a list of the plants is desired in
return, the sender should enclose a number with each specimen,
so that the names can be given to correspond with the numbers.
All desirable material will be preserved and kept in the her-
barium here where it will be available for comparison and for
study. For this reason the locality and date of collection and
other notes of interest should accompany the specimens. After
one has had some experience in the collection of these plants
and in noting the important characters their specimens will be
of more value. It is possible in this way for collectors to aid us
in bringing together material from different sources which
should assist in making these studies and illustrations of mush-
rooms more comprehensive and of wider usefulness.

From students of the fungi who have duplicate material in any
of the groups, the Botanical Department will welcome contri-
butions to the herbarium. Such gifts are certain to be of great
usefulness at a center where students come for research. Not
only is this branch of botanical study, as well as others
emphasized, it is important to consider that mycological study
here contributes to, and is supplemented by, other fields of
research in related departments, as well as in the work of the
Experiment Station, and in that of the newly organized College
of Forestry.

Specimens may be sent to either of the following addresses :
PROFESSOR GEO. F. ATKINSON,

Botanical Department,
Cornell University, Ithaca, N. Y.
or,

CORNELL MYCOLOGICAL CLUB, Ithaca, N. Y.

Persons desiring to join the Club should send name with the
annual fee enclosed, to either of the above addresses. The fee
should not be sent in postage stamps, but preferably in a postal
note when in so small a sum, unless the "quarter " is enclosed

5i6 BULLETIN 168. (56)

in a mailing card for the purpose. The cost of sending will be
reduced where several from the same locality choose to send
names and fees in a single letter. The exact address should also
be given for each person, with the street number where
necessary.

Those wishing to take up the study of the fungi would find it
profitable to attend some school where suitable opportunities
are offered for beginners. A course in mycology* (devoted
especially to the mushrooms) will be given during the summer
of 1899 in tne Botanical Department of Cornell University.

* Besides the course in mycology, courses in general morphology and
physiology of plants, as well as a course in ecology are offered in the sum-
mer school especially for teachers. The catalog of the summer school can
be obtained by addressing, The Registrar, Cornell University, Ithaca, N.Y.
A full year's course in mycology is given during the regular annual
session of the University as described in the annual Register.

NOTE. — The author was asissted in making some of the photographs
illustrating this bulletin, by Mr. H. Hasselbring, and Mr. B. F. White.

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