Albert Francis Blakeslee.

Trees in winter; their study, planting, care and identification online

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tasting bark and twigs of any unknown tree-like species.

The bark varies in character according to the age of the tree.
In the young tree the bark is smooth, but, as the trunk expands
from the growth of the wood within, the covering of dead bark
outside is forced to crack in a variety of ways giving rise to
characteristic fissures and ridges which become more prominent
as the tree grows older. The bark of few trees such as the Beech
(p. 295) and the American Hornbeam (p. 279) remain smooth,
their outer layers expanding with the growth of the tree. The barks
of others as the Paper and Yellow Birch (p. 283) stretch and peel
off in thin papery layers. In the Birches (p. 289) and Cherries
(p. 369) the breathing pores (lenticels) become horizontally elon-
gated to form narrow transverse streaks which are characteristic for
these forms. When ridges or scales are formed they may be close
and firm and with difficulty removed from the trunk as is the case
with the bark in the Black Oak group or, on the other hand, they
may be easily rubbed off as are the scales of the bark of the
White Oak and of most members of the White Oak group. Bark
of this latter type is called flaky in our descriptions and this
distinction between barks that are flaky and those that are not
flaky is of considerable importance in classification. To avoid
confusion little notice is taken of the minute scales that are
likely to occur on the surface of both types of bark. The bark
may come off in large sheets as in the Shag-bark Hickory (p. 269)
and the Sycamore (p. 349), and the ridges may be long as in
the Chestnut (p. 297) or short and run together to fonn more
or less perfect diamond-shaped areas as in the White Ash (p. 423)


but these as well as other differences in the sculpturing are shown
in the photographs and do not require further discussion.

Tivigs — The unqualified, word twig refers in the descriptions
to the growth of the past season only. Older twigs and branch-
lets are the designations employed for the small growth of several
seasons. The Horse-chestnut (fig. 20) has been taken as a con-
venient form to illustrate the various markings found on the twig
and is discussed on page 39.

In some species, such as the Black Birch (p. 281) and the
cultivated Cherry (p. 3G9), a sharp distinction can be drawn
between rapidly-grown long shoots which have elongated inter-
nodes and continue the growth of the twig and slowly grown
short spurs which have greatly abbreviated internodes and crowded
leaf-scars. The fruit-spurs of the Apple (p. 353) and Pear
(p. 351) are of this latter type.

Of the distinctive 'characters given under the heading twigs may
be mentioned the relative thickness, whether stout or slender, the
presence or absence of thorns or prickles, the color, the taste as
indicated under the discussion of the bark, and the character of
the surface, whether smooth or more or less covered with hairs.
Twigs are called hairy when the hairs are individually distinct,
downy when they are fine and numerous, and woolly or cottony
when they are twisted together into a more or less felt-like mass,
but these distinctions cannot be always sharply drawn. A twig
if smooth may be dull or shiny in appearance. The lenticels are of
most distinctive value in those forms like the Birches (p. 289), in
which they become horizontally elongated with age. The color,
size and shape of the pith are often characteristic as seen in the
wide salmon-colored pith of the Kentucky Coffee Tree (p. 381)
and the star-shaped pith in the Oaks and to a less degree in the
Poplars (fig. 100). The pith, however, frequently varies consider-
ably in color in a given species. Some few trees have their pith
separated by hollow chambers such as the Hackberry and the
Butternut (fig. 101) or have solid pith but with woody cross
partitions such as the Tupelo.

Leaf -scars — The arrangement of the leaf-scars form primary
divisions in the classification. They may be opposite with two


scars at a node as in the Horse-chestnut, or alternate with only
one scar at the node as in the majority of species. Alternate leaf-
scars may be arranged along the twig in two longitudinal rows
when they are said to be 2-ranhed, as in the Mulberry (fig. 103),
or in several rows when they are more than 2-ranked as in the
Poplars (fig. 100). Twigs sometimes if rapidly grown have the
leaf-scars which are normally opposite pulled apart to appear al-
ternate, but the typical condition will be found on other parts of
the tree. A few species like the Chestnut sometimes take the
2-ranked, and sometimes the more than 2-ranked position, and
the number of ranks in other forms may be at times somewhat
obscured by a twisting of the twig. The distinctions in the main,
however, hold good and where a doubt is likely to occur in regard
to the arrangement, a place has been made in the key for the
species in both the 2-ranked and the more than 2-ranked groups.

The size and shape of leaf-scars are important factors in identi-
fication. They may be very narrow as in the Pear and their
upper margins may be flat or convex as in the Black Ash (p. 427)
or deeply notched as in the White Ash (p. 423) or form a band
nearly surrounding the bud as in the Sycamore (p. 349). They
may become dingy and inconspicuous or be sharply distinct
by color contrast with the rest of the twig. Thus the Elms and
the Poplars have their leaf-scars covered with a light-colored cork-
like layer which makes them conspicuous irrespective of their size.
Leaf-scars may be level with the twig or more or less raised with
tbeir surfaces parallel with the twig or making various angles
with it up to a right angle. Ridges in some cases run down
the twig from the base and corners of the leaf-scar.

At the bases of the leaves of some species a pair of small leaflets
called stipules are regularly formed and leave, at the fall of the
leaf, more or- less definite stipule-scars at either side of the leaf-
scar as, shown in the Carolina Poplar (fig. 100).

The number, the size, the relation to the surface of the leaf-
scar whether sunken or projecting, and the distribution of the
bundle-scars form important points of distinction. When they are


indistinct, as is frequently the case, they may be revealed
if a thin slice is taken off the surface of the leaf-scar.
This surface section must be very thin, however, since
the number of bundle-scars exposed by a deep cut is
often different from that on the surface, and this latter
number is the one used in the keys and descriptions. A
distinction is made between a group in which the
bundle-scars form a single line and a second group in
which they are variously scattered and grouped or in
a double line.

Buds — In regard to their position buds are ter-
— 5X minal or lateral. Buds produced at or near the nodes
but not in the axil of a leaf-scar are called accessory
buds. Of these there are two kinds: Superposed buds
located above the axillary buds and collateral buds
located at either side of the axillary buds. The former
are shown in the Butternut (fig. 101) and the latter in
the Red Maple (fig. 102). Classified according to what
they produce there are flower buds which contain the
rudiments of flowers, leaf buds which contain rudiments
of leaves, and mixed buds which produce both flowers
and leaves. Flower buds are generally stouter than leaf
-? Most species by the end of the growing season have
o-fcaroiTna^-^^^"^^^ terminal buds which remain through the winter
sx— supuie ^^^ ^^® destined to continue the growth the following
p_star-^^^' spi'i^g- I^ some species, however, such as the Mulberry
shaped Pith(fig, 103)the terminal bud together with the tip of the
twig dies away and drops off before the beginning of winter
leaving a small scar at the end of the twig. The presence or
absence of the terminal bud is a very valuable point of distinction
and is used throughout in the keys. Unfortunately it is not always
possible at a cursory glance to say whether the terminal bud is
present or absent and a hand-lens must generally be used for an
accurate determination of this point. In the Mulberry figured,
the self-pruning scar formed by the dropping off of the terminal
bud is perched on the tip of the twig with the topmost lateral bud
obviously in the axil of the last leaf -scar. Frequently, however,.




the self-pruning scar may be nearer the lateral bud which bends in
and gives the appearance of being terminal. The presence of a
leaf-scar below it shows that it is in fact axillary,
but since leaf-scars are sometimes present toward
the end of twigs without buds in their axils the
presence of the self-pruning scar at the twig end must
be used as the decisive sign that the terminal bud is
really absent.

Aside from the color, the presence or absence of
hairs, stickiness, fragrance and other such surface
characters, the position of the buds in relation to the
twig may be of importance. Buds that lie close
up against the twig as those of the Small-toothed
Aspen (p. 255) are called appressed, while those
that project more or less away from
the twig as those of the Carolina
Poplar (fig. 100)are called divergent.
In the Common Locust and a few
other forms the buds are sunken
below the surface of the twig, and
can be found only by cutting the
twig lengthwise through the leaf-
Fig, 101. Twig scar.

of Butternut.

tr— terminai^^ The characters of the bud-scales Fig! 102. Twig of
ax-axiiiaryj^^- of most importance are the shape, .^l^^^^n^^y bud.
sp— Superposed the number visible in the unmutil- ci— coUaterai

accessory bud. accessory bud.

p— chambered arrangement — whether alternate or

opposite — and the number of ranks they f onn on
the bud.

Fruit — The fruit generally forms a good means of identi-
fication when it can be found. Unfortunately there are a number
of limitations to its use for this purpose. In the first place many
species of trees do not fniit every year, and it may happen that
the species under examination is not in its fruiting period and
consequently all the trees of the region will fail to show fruit.
Again, in some species such as the ilsh the sexes are separate and
consequently only female trees can ever be expected to bear fruit.
The fruit generally does not remain on the tree throughout the
winter but if the tree is sufficiently isolated from other species,


a careful searcli on the ground will often be rewarded b}' the
finding of specimens of fruit that one can feel sure came from
the tree in question. However, some species such as the Poplars
and the Red and Silver Maples scatter their fruit early in spring,
and fmiting material of such forms in consequence is not to be
looked for in winter. The immature fruit of some species may be
found on the tree in winter and be of value in identification.
Thus the presence of young acorns on an Oak in winter shows
that it belongs to the Black Oak group.

The staminate flowering clusters are of similar
diagnostic value in certain groups, their presence
or absence, for example, separating the American
Hornbeam from the Hop Hornbeam.

Comparisons — Under this heading are con-
trasted the difi^erent species that are considered
likely to be confused. It is believed that the in-
formation in this section will prove more valuable
to one with some knowledge of trees than the more
detailed descriptions first given.

Distribution — The habitat first discussed under

T^- mo ^io. r.f ^liis heading shows in what kind of locations

Muiberry.^_^^^^ as to soil, moisture and exposure the species

bud often mis- normally arrows. The information mav be of iden-

taken for a ter- . , ^

minai bud. tificational value by elimination. Thus if one finds

sc — self-pruning -^

scar left by fall a ccdar-like tree on a hillside pasture one can be

of real terminal ^

bud and tip of gure it is not a Coast White Cedar since this latter


species grows only in swamps. In like manner the geographical
limits may assist in identification; a Pine found growing wild in
Rhode Island or Connecticut, for example, could not be the Jack
Pine since this is a northern form found native only in the northern
New England states. Although some cultivated trees have escaped
from cultivation, an introduced tree is generally characterized
by the places in which it is found growing.

Wood — Under this heading the information given in regard to
the characters of the wood and the economic value of the species
is of practically no value for purposes of identification of standing
timber, but may prove of general interest to the student of trees.




Despite the fact that the appearance of the bark and the method
of branching are almost exclusively depended upon by the experi-
enced woodsman in recognition of species, these characters are
difficult of precise description and not adapted to use in a key.
The twigs therefore with the scaly buds and leaf-scars are used, as a
basis of the following keys. The word "twig" in the sense here
used, it should be remembered, denotes the growth of the past
season only, and the word "bark" refers to the bark of the trunk
and older limbs and not of the twigs or branchlets. The student
should read the foregoing section and note the limitation of terms
and characters used in the following pages.

Before attempting to identify an unknown tree it is necessary
to have good material to work with. Care should be taken that
the twigs selected are normal in appearance, being neither abnor-
mally stunted in growth nor unusually elongated as are twigs on
young sprouts. Frequently the species may be determined by an
inspection of the twigs alone but notes on the character of the
bark and the habit of growth as well as specimens of the fruit will
generally be found useful and sometimes necessary.

In the key a choice is given between two paragraphs preceded
by the same number. This choice leads to a new number or to the
name of the species followed by the page where a detailed
description of the tree may be found. The White Ash may be
used to show the method of procedure. Starting with N'o. 1 we
have the choice between trees with "leaves persistent and green
throughout winter" and trees with "leaves 7iot persistent and green
throughout winter." We choose the latter and this takes us to No.

11 where the decision must be made between "leaf-scars opposite
or in 3's" and "leaf-scars alternate." The leaf-scars on the Ash
are opposite and we take the first 11 and are led to No. 12. At

12 we have the alternative between "leaf-scars, or some of them, 3
at a node" and "leaf-scars always 2 at a node." The first pair
of contrasting characters mentioned are always the most important.
The constant presence in the Ash of two leaf-scars at a node is
sufficient to cause us to choose the second 12, and our choice is
corroborated by the position of the bundle-scars and by the presence
of a terminal bud, so we pass to 13. The upper lateral buds of


the Ash are not covered by persistent bases of leaf-stalks and there
are 2 or more pairs of scales to the leaf buds, we therefore pass
to 14. The relatively small size of the buds and their freedom
from stickiness takes us to 15 where the number of the bundle-
scars and the other characters given show us that we have in hand
a twig of one of the Ashes. We now turn to N"o. 165 and confirm
our determination of the genus by reading the general description
of the Ashes. To find out which Ash we are dealing with we
procede with the key of the Ashes and, knowing that the leaf-scars
in our specimens are deeply concave on their upper margins, we
conclude that we have the White Ash {Fraxinus americana).
At page 422 we find a detailed description with photographic
illustrations of this species and may learn the winter characters
of the tree not already given in the key. If the description and
photographs do not correspond to the tree under investigation, we
know that we have gone astray at some point in the key, and
turning back we repeat the analysis taking if need be the other
alternative of a pair where the choice had been doubtful.

The meaning of unfamiliar terms may generally be found in the
glossary. Often, however, the photograph offers a better explana-
tion. Thus in distinguishing the Carolina from the Lombardy
Poplar, the word "spire-shaped" as applied to the habit, can best
be understood by reference to the picture of the latter species.
"WTien a choice within a number seems impossible from the infor-
mation available, trial should be made of both contrasting para-
graphs. In the key to the Oaks, for example, the character of
the bark — whether flaky or not flaky — is used as a distinguishing
mark. AYith only the twig at hand, it may still be possible to trace
the name by trying the tree first under "bark flaky" and if this
does not lead to the correct name, then under "bark not flaky."
It might seem needless to suggest that both the contrasted parts
of each number encountered should be read but work with students
has shown that such a suggestion may be useful.

Sometimes a tree is variable in the characters used m the key.
Thus the Chestnut has terminal buds sometimes present on the twigs
though they are generally absent. In such cases, however, and
where there is a legitimate doubt as to whether the tree should be
placed in the first or the second group, it has generally been placed
in both so that either of the two choices should lead to the correct


name. The determination of the presence or absence of the ter-
minal bud is perhaps the greatest pitfall likely to be found in the
use of the key, but should give little difficulty if the discussion
in the introduction is understood and the terminal scar is looked
for with the aid of a hand-lens.



1. Leaves persistent and green throughout winter (Evergreens) ...2

1. Leaves not persistent and green throughout winter (dead leaves
often persistent in the Oaks and Beeches) . 11

2. Leaves broad, prominently spiny-margined. Holly (Ilex opaca) p.396

2. Leaves narrow, often minute and scale-like; Conifers (i.e. cone-
bearing trees) 3

3. Leaves, except scale-leaves, needle-shaped, in definite, generally
sheathed clusters on the sides of the branches Pine (Pinus) 85

3. Leaves, not in definite clusters 4

4. Leaves opposite or in 3's, therefore 2 or 3 at a node 5

4. Leaves alternate, scattered, therefore only 1 at a node 8

5. Leaves whorled in 3's, all alike, whitened above and green below,
awl-shaped, sharp-pointed and spreading; fruit bluish, berry-like;
a shrub or low tree. (See also juvenile condition of Red Cedar) . .
Common Juniper (Juniperus communis) p.244

5. Leaves opposite in 4 ranks, minute, scale-like, closely overlapping 6

6. Young twigs prominently flattened and forming a flat, 2-ranked,
fan-shaped spray often mistaken for the true leaves which are
minute and of two shapes, those on edges of twig being narrower,
those on flat sides being broader and more abruptly pointed with
each leaf generally showing a conspicuous raised glandular dot;

fruit a thin-scaled, oblong, woody cone

Arbor Vitae (Thuja occidentalisj p.242

6. Young twigs not prominently flattened; fruit spherical 7

7. Spray somewhat fan-shaped; young twigs not prominently 4-angled;
leaves all alike in shape, some of them with prominent raised

glandular dot on back; fruit a spherical woody cone

Coast AVliite Cedar (Chamaecyparis thyoides) p.240

7. Spray not fan-shaped; young twigs with typical leaves are prom-
inently 4-angled; leaves without conspicuous glandular dots, of two
kinds; (a) the juvenile form — awl-shaped, spiny-pointed and
spreading, in 2's or 3's at a node and resembling leaves of Common
Juniper, the usual leaf form on young trees but generally to be
found on some parts of older trees; (b) the typical form — smaller,

scale-like and closely appressed; fruit bluish, berry-like

Red Cedar (Juniperus vir giniana) p.246

8. Leaves distinctly flattened 9

8. Leaves not distinctly flattened, needle-shaped, 4-angled, sessile on
projections of the bark Spruce (PiceaJ 91

9. Leaf about 1 cm. long with definite leaf-stalk, leaving prominently
projecting scar when detached. Hemlock (Tsuga canadensis) p.238

9. Leaf about 2 cm. or more long, without leaf-stalk, leaving a flat
or only slightly raised scar when detached 10

10. Buds small, nearly spherical to broadly ovate, their scales covered

and glued together by resinous coating; leaf-scars flat

Balsam Fir (Ahies halsamea) p.236

10. Buds larger, narrow conical, without resinous coating; leaf-scars
slightly raised Ooug;las Fir (Pseudotsuga taxifolia) p.234

11. Leaf-scars opposite or in 3's, therefore 2 or 3 at a node 12

11. Leaf-scars alternate, therefore only 1 at a node 16

12. Leaf-scars or some of them 3 at a node; bundle-scars in an
ellipse; terminal bud absent Catalpa (Catalpa) p.428

12. Leaf-scars always 2 at a node; bundle-scars not in an ellipse;
terminal bud present 13

13. Leaf buds with only a single pair of scales; lateral buds, at least

the upper ones, covered by persistent bases of leaf-stalks

FloweriuR Dogwood (Cornus florida) p.418

13. Leaf buds with 2 or more pairs of scales; lateral buds not covered
by persistent bases of leaf-stalks 14


14. Terminal buds large, over 1.5 cm. long, sticky or varnished; leaf-
scar larg-e, inversely triangular; bundle-scars 3-9, conspicuous

Horse-chestnut (Aescuius HippocastanumJ p.414

14. Terminal buds smaller, under 1.5 cm. long, not sticky-varnished;
leaf-scars smaller 15

15. Bundle-scars, minute, numerous in a U-shaped line often more or

less confluent; bud-scales scurfy (i.e. rough-downy)

Ash (Fraxinus) 165

15. Bundle-scars not minute, generally definitely 3 in number; bud-
scales not scurfy Maple (Acer) 155

16. Stipule-scars entirely encircling the twig- 17

16. Stipule-scars absent or if present not encircling the twig 19

17. Leaf-scar almost completely surrounding the bud; terminal bud
absent; (the last lateral bud may appear to be terminal but absence

of terminal bud is shown by small scar at end of twig)

Sycamore (PlatanusJ p.348

17. Leaf-scar not surrounding the bud; terminal bud present 18

18. Buds ovate to conical, hairy at least within; scar of rudimentary

leaf surmounting decurrent ridge on side of bud

Magnolia (Magnolia) 142

18. Buds flattened oblong, smooth without and within; scar of rudi-
mentary leaf, if present, at base of bud

Tulip Tree (Lirioclendron Tulipifera) p.340

19. Twigs with thorns, spines, or prickles, or branches ending in
thorns 20

19. Twigs without thorns, spines, or prickles 27

20. Spines in pairs at the nodes, or twigs covered with weak hair-
like prickles 21

20. Spines not in pairs at the nodes, twigs not covered with weak
prickles 22

21. Buds rusty-hairy, more or less covered by bark; terminal bud
absent Locust (Rohinia) p.38S

21. Buds, red, exposed; terminal bud present; a shrub

. . . .Prickly Ash (Zanthoxylon americanum) under Comparisons p.388

22. Thorns lateral, regularly placed on the twig at or near the
nodes 23

22. Thorns terminal 25

23. Thorns generally branched, situated above the nodes; buds several

in a longitudinal row, the lower ones covered by the bark

Honey Locust (Gleditsia triacanthus) p.382

23. Thorns generally unbranched on twigs, situated at the nodes;
sometimes branched thorns on trunk; buds exposed 24

24. Thorns generally present at all the nodes; bundle-scar single

[email protected] Orange (Madura pomifera) under Comparisons p.360

24. Thorns generally absent from many of the nodes; bundle-scars 3.
: Hawthorn (Crataegus) p.360

25. Terminal bud absent but leaving a terminal scar on twig

Plum (Prunus) 151

25. Terminal bud present, at least on spineless branches 26

26. Tree with bushy habit of growth; twigs with characteristic
licorice-like taste, generally reddish-brown, more or less pale-
woolly at least toward apex; lateral buds blunt, flattish, appressed
and more or less pale-woolly Apple (Pyrus Malus) p.352

26. Tree with upright habit of growth; twigs without characteristic
taste, generally yellowish green and generally smooth; lateral buds
sharp-pointed, smooth or sometimes slightly downy, generally not
flattened nor appressed Pear (Pyrus communis) p. 350

Online LibraryAlbert Francis BlakesleeTrees in winter; their study, planting, care and identification → online text (page 14 of 31)