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ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

SERIES 4 VOLUME V

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PUBLISHED BY THE

ARNOLD ARBORETUM

JAMAICA PLAIN, MASSACHUSETTS

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ILLUSTRATIONS

Forsythia europaea, F. intermedia, F. viridissima, F. ovata, F. sus-
pensa, Plate I, p. 5.

Forsythia intermedia spectabilis, F. ovata, Plate II, p. 7.

Prunus Sargenti (formerly P.serrulata saehalinensis) , Plate III, p. 11

Pink-flowered Rhododendron Schlippenbachii, Plate IV, p. 19

Rhododendron yedoense poukhanense, Plate V, p. 21

Part of the Chinese Collection on the top of Bussey Hill in the Arnold
Arboretum, Plate VI, p. 27

Title-page of Jacquin’s “Selectarum stirpium americanarum historia’*
(cir. 1780), Plate VII, p. 35

Frontispiece and first page of “Gart der Gesundheit” 1485, Plate
VIII, p. 39

Clematis macropetala, a charming Chinese species of the Atragene
Type, in the azure-blue flowers, Plate IX, p. 45

Clematis “Duchess of Albany,” one of the Texensis Hybirds, Plate
X, p. 47

Clematis Belle of Woking, ” a double-flowered silvery-gray hybrid,
Plate XI, p. 51

Clematis “W.E. Gladstone,” a fine hybrid, with flowers of heavenly
blue, Plate XII, p. 58

Clematis lanuginosa, a Chinese large-flowered species from which many
of the hybrids have been derived, Plate XIII, p. 55

Berberis koreana, a worthy successor to the old-fashioned B. vulgaris,
Plate XIV, p. 61

Berberis circumserrata, another handsome shrub of distinctive habit,
Plate XV, p. 65

Berberis Gilgiana, hardy in Boston and valued for its fruit and autumn
color, Plate XVI, p. 69

V iburnum prunifolium, Plate XVII, p. 75

Viburnum dilatatum xanthocarpum, one of the yellow-fruited vibur-
nums, Plate XVIII, p. 77

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ARNOLD ARBORETUM

HARVARD UNIVERSITY

-$-•

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V APRIL 2, 1937 Number 1

THE FORSYTHIAS

FORSYTH IAS are among the most common of garden shrubs, and
their early yellow blossoms are a boone to many a dreary garden
which has looked lifeless a greater part of the winter. They were first
introduced into America about 100 years ago. Probably no other hardy
wood shrubs which have been introduced from the Old World into our
gardens can equal or surpass the forsythias in cheerful beauty, which
is developed at a season when there are comparatively few other com-
petitors so attractive.

All the plants in this genus have yellow flowers which open in late
March or early April before the leaves appear. All can be grown in
many different types of soil and can withstand the tough, trying con-
ditions of the city garden better than many other shrubs. Only one,
the green-stem forsythia ( Forsythia viridissima, ) has autumn color, and
this is a lovely purplish red.

Unfortunately many public plantings of forsythias are sadly muti-
lated because of lack of intelligent care in pruning. Forsythias should
be given plenty of room in which to grow and expand. They should
not be crowded closely together for any reason except to make a good,
dense bank planting where the whole object is to cover the ground.
Many times when a single bush is used, it will be placed only two or
three feet from a walk when actually it should be placed 8 to 1 0 feet
from the walk, in order to give the plant plenty of room to expand
fully at maturity. If the plants are pruned from the side, this neces-
sarily cuts off the lovely drooping branches and spoils the entire effect,
leaving only the unsightly base and a few branches ending prema-
turely in mid-air when they should be allowed to arch gracefully to-
ward the ground.

[i]

Pruning. Forsythias should be pruned only after flowering. This
is not because of anything peculiarly inherent in the plant itself, but
simply because the flower buds are present all winter long, and if the
plant is pruned before it flowers a large proportion of the buds would
be needlessly destroyed before they have an opportunity to open. Con-
sequently, it is always better to leave the plants alone until they have
blossomed, and then, if necessary, do the required pruning. Also, after
the flowers are gone the young shoots commence active growth, and
such pruning as has been necessary will be considerably less apparent.
It is usually best when pruning forsythias to leave as many of the
graceful side branches as possible.

Fortunately, forsythias, like lilacs and privets, w7hen necessary, can
withstand the most severe pruning. As an example, this spring at the
Arboretum it w7as necessary to cut off one of our bank plantings of
forsythias to the ground, because it had become so overgrown that it
was a physical impossibility to cut out only the dead wood. Because
of the large amount of dead w ood and the overgrown condition of the
mass planting, the shrubs did not bloom nearly as well during the
past few7 years as they should, thus requiring this drastic treatment.
These plants will now sprout vigorously from the base and within two
or three years will amply repay such extreme treatment by yielding
a far superior crop of flow ers.

Hardiness. Although the forsythias are classed as hardy, there is
a limit to the endurance of such severe temperatures as wre often ex-
perience in New7 England. The plants themselves may withstand lower
temperatures than the flow7er buds. It is common, after a severe win-
ter in New7 England, to see flowTers only on those branches w7hich have
been protected by the snow7 during the winter, for it often happens
that with temperatures of 15 to 20 degrees below7 zero, unprotected
flow7er buds will be killed. This has often happened in the Arboretum.
There is, how7ever, one forsythia w'hich apparently can withstand these
lower temperatures and still bloom. This is the Korean forsythia, F.
ovata, introduced by the Arboretum in 1917. F.europaea has also proved
hardy, but its flowrers are not as handsome as those of the other species.

Forsythia suspensa. The common type of this species is the va-
riety Sieboldii , which is a shrub with very pendulous branches, often
touching the ground and rooting at the tip. It was the first exotic
forsythia introduced into Europe. It is a native of China and first
reached the Netherlands in 1833. Now7 it is common in cultivation
everywhere. There is the vigorous upright growing Fortunei, intro-
duced from China in about 1860. In habit this is not nearly so droop-

ing as var. Sieboldii and cannot be substituted for it, particularly where
it would be expected to cover arbors, walls, or to ramble over rocks.
Another variety, F.snspensa pallida , must have originated prior to 1912
and is simply of value because it has flowers of a considerably lighter
yellow than the other type. Although there are several other varieties
known ( variegata , pubescens , and atrocaulis with its young growth pur-
plish in color), these are not sufficiently outstanding to be strongly
recommended and are more tender than the type.

Forsythia viridissima. Robert Fortune is responsible for first send-
ing this plant to Europe from the gardens of China in 1844. It is not
as hardy in New England as the other species and often kills severely,
even to the ground. It is upright in habit of growth, having the ad-
vantage of developing a rather good, dark red autumn color in the
fall, a character which most of the other forsythias lack.

The manner in which these plants were first brought from Japan
and China has been described in a most interesting way by Robert
Fortune. In those days the trip from Japan to England was a long
and tedious one around the Cape of Good Hope. The trip was not a
matter of a few weeks, but one of four to five months. It was often
difficult to keep seeds in a viable condition for that period of time, let
alone cuttings and young plants. Then, too, if potted plants were
taken there was the problem of protecting them against salt spray and
of watering them over so long a period of time, for fresh water on
sailing ships was limited.

This difficulty was surmounted by the early plant explorer by using
one of the then new “Wardian” cases, which are now more commonly
used in the form of solariums. These were simply pieces of glass sealed
together so that no air or moisture escaped. Sufficient soil was placed
in the base in which to plant the rooted cuttings or young plants. Just
before the ship sailed, the plants were well watered and the cases
sealed for the trip. In this way the water requirement was decidedly
reduced, and even if the plants did occasionally need additional water
this could easily be supplied. One of the most important factors was
to see that the cases were carefully sealed, not so much to keep the
moisture in, but to keep the salt water out. If a very small amount
of salt water got in, it would result in serious injury. The sealed cases
had to be placed where there was plenty of light, and according to
Fortune, “large vessels with poops” were always to be preferred
where there was any choice.

Probably more hardy than F .viridissima is its Korean relative, var.
koreana , which was introduced by the Arboretum in 1919 through

seeds sent here by the Department of Forestry in Korea.

Forsythia intermedia. Since forsythias cross freely, hybrids often
occur, and F .intermedia is one that has proved the most promising. It
is a cross between the two Chinese species, F.suspensa and F.viridis-
sirna , originating in Europe shortly before 1880. It is considered su-
perior to both its parents, particularly its very common variety spec-
tabilis , which has individual flowers 1| inches across. This can well
be termed the most handsome of all the golden-bells because of its
large, dark yellow flowers and the profuseness with which they are
borne. It is extremely floriferous, and well-grown stems, 6 to 8 feet
long, are literally covered along their entire length with the deep
yellow flowers.

Two other varieties are of importance. The variety primulina , which
originated in the Arboretum in about 1910, has the best pale yellow
flowers of any forsythia. The variety vitellina is also considered good
because of its deep yellow flowers. Since F .intermedia is a hybrid, it is
sometimes confused with the Chinese species.

As an aid in distinguishing between these plants, two helps are
given; a key reproduced from Rehder’s Manual of Cultivated Trees and
Shrubs , and illustrations showing the general outlines of the leaves
of the different forms.

Key to Forsythias (After Rehder’s Manual )

A. Brs. hollow, with solid pith at the nodes: lvs. often 3-foliate

1. F.suspensa

A A. Brs. at least partly with lamellate pith.

B. Mature brts. greenish or brownish: lvs. elliptic-ovate to lan-
ceolate.

C. Lvs. serrate, at least above the middle, only occasionally
entire, 7—14 cm. long.

D. Pith usually solid at the nodes, wanting or lamellate
between the nodes ; lvs. on vigorous brts. sometimes

3-parted 2. F. intermedia

DD. Pith lamellate throughout, only at base of vigorous
brs. wanting between the nodes : lvs. hardly ever 3-

parted 3. F.viridissima

CC. Lvs. usually entire or with few shallow teeth, 5-8 cm.

long, never 3-parted 4. F.europaea

BB. Mature brts. yellowish : lvs. ovate or broad-ovate, serrate,
never 3-parted 5. F.ovata

PLATE I

F.europaea F. ovata

F. intermedia F. viridissima F. suspensa

Branches of five different Forsythia species showing normal leaf outlines. In identifying
Forsythias, these illustrations should be used as an aid only, to the key on the opposite page.

Forsythia ovata. This Korean forsythia is a comparatively recent
arrival, having been introduced into America by the Arnold Arbore-
tum in 1917. E.H. Wilson found it growing in the Diamond Mountains
in Korea. Although its flowers are smaller and not as numerous as are
those of F .intermedia, it is the earliest to bloom and hardiest of all the
forsythias and for this reason should be used in northern plantings
where other species and varieties are subject to winter killing. Its
leaves are rounded and ovate. It is not very dense in habit of growth,
but eventually forms a well-rounded shrub, 6 to 8 feet tall. The very
fact that it is the hardiest should make it valuable to the plant breeder.

Forsythia europaea. This is the only forsythia native of Europe
and the only non-Asiatic species. It was first discovered in the moun-
tains of Albania in 1897. The flower buds are proving rather hardy,
but it has less ornamental value than any of the others.

NOTES

Friends of the Arnold Arboretum will be glad to note that the num-
ber of subscribers to its Bulletin of Popular Information is now larger
than it has been for many years. Through this medium, the Arbore-
tum is able to reach an ever increasing number of friends. We are
always glad to send sample copies to interested individuals and invite
our readers to call our attention to those who may profit from it. It
is our desire to extend the usefulness of the Arboretum as much as
possible.

For the benefit of those who did not subscribe to the 1986 issue in
time to receive a complete set, there is still a limited number of the
following numbers available at 15 cents each: Tree Troubles, The
Flowering Crabapples, Just about Lilacs, Woody Plants with Orna-
mental Fruits, and Autumn Color. Address the Arnold Arboretum,
Jamaica Plain, Massachusetts, for those you wish, enclosing the equiv-
alent of the price in stamps.

Recent Bulletin subscribers for the year 1936 will automatically re-
ceive the Bulletin for 1937, since many 1936 issues are exhausted.

The Arnold Arboretum is actively cooperating in the revision of
Standardized Plant Names, originally published in 1928 and since that
time widely used by the horticultural industries. There are now ap-
proximately 15,000 new names to be added to the original 40,000
entries. While much detailed work is involved, it is hoped that the
revised edition will be available by the first of next year.

Donald Wyman

PLATE II

Forsythia intermedia spectabilis Forsythia ovata

This shows the difference in the size of the flowers between these two species.
The flowers of F. intermedia spertahUis are the largest and the most profuse of any
of the forsvthias. The Korean forsythia ( F. or at a ) is the hardiest.

SPRAY PROGRAM AT THE ARNOLD ARBORETUM

Spray

Amount

When

Material

to Apply

to Apply

Scale insects

Miscible oil

1-15

Feb. 15 to early April

Evonymus scale

6 6 6 6

1-30

when plants are dormant

1-50

in the summer

Pine-leaf scale

6 6 6 6

1-30

early April

Spruce-gall aphids

6 6 6 6

1-30

April 15

Larch case-bearer

Arsenate of lead

2 lbs. -50 gal.

when young are feeding

Golden oak scale

Miscible oil

1-15

early spring

Spring canker-worm

Arsenate of lead

2 lbs. -50 gal.

as soon as young appear

Willow leaf beetle

n a < «

2 lbs. -50 gal.

early June, applied to un

der surface of the leaves

Lace-bug of Rhododendrons Sunoco oil 1—70 as they hatch in the spring

1-60 in August on a partly
cloudy day when the tem-
perature is not over 80°F.

Elm leaf-beetle Arsenate of lead 3 lbs. -50 gal. early June. A second

spray may be necessary
for a second brood

Red spider on evergreens Sunoco oil 1—100 applied in summer as a

fine mist on a cloudy day
when temperature is not
over 80° F.

White pine weevil cut out borers and dead

branches

Borers dig out

L. V. Schmitt

Because of many new subscribers who were unable to get a complete set of
1936 issues, this Spray Program is being reprinted from the 1936 Bulletin.
Wherever a miscible oil is mentioned, recommendations have been based on
Sunoco Oil only, which has proved satisfactory at the Arboretum.

[8]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

JJt

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V APRIL 23, 1937 Number 2

SOME SINGLE FLOWERING JAPANESE CHERRIES

WHEN the Japanese cherries bloom in the spring they always
lend a touch of exotic beauty and fragrance which is unsurpassed
by any other group of flowering trees. In America the public is be-
coming increasingly conscious of their beauty, and because of the wide
publicity given the plantings in Washington many cities and civic
organizations are starting local collections. One of the most recent of
these, and perhaps the largest, is in the Fairmount Park System of
Philadelphia.

Japanese cherries were introduced into America approximately one
hundred years ago. Prior to that time it was most difficult to send
plant material of any kind out of Japan. In 1846 the old Ellwanger
and Barry Nursery Company of Rochester, New York, listed a Japa-
nese cherry in its catalogue, and this was probably the first time any
were offered in America. It is probable that the variety first grown
here was the pendulous form of Prunus subhirtella. In 1912 the Mayor
of the city of Tokyo presented to the city of Washington as a token
of friendship two thousand Japanese cherry trees, which have done
much to promote American interest in these plants. Many of them
were planted in Potomac Park in Washington where they are now
creating nation-wide interest each spring when they bloom.

Unfortunately, most of the double-flowering Japanese cherries
should be considered as comparatively short-lived trees. This is par-
ticularly true of many of the double-flowered forms, which often have
to be replaced about every fifteen years. Under favorable growing
conditions they may last considerably longer, but it is well to con-
sider them as a short-lived group in order to avoid later disappoint-
ment. The Sargent cherry is the exception. This is the hardiest of all

and grows to a sizable tree of a ripe old age. One of the first plants
in this country, introduced forty-six years ago, is still growing in the
Arnold Arboretum and is in perfect condition.

In the colder sections of the United States the Japanese cherries
are not hardy, hut in general they may he considered as doing well
in those places where peaches are hardy. In southern Maine, for in-
stance, they cannot he expected to do well although in the states
bordering the Great Lakes, where the temperatures are somewhat
moderated, there are some excellent plantings. In the drier portions
of the mid-west they soon succumb, hut on the Pacific Coast they
thrive from Washington to southern California. Even as far south as
the middle of Georgia, Alabama, and Mississippi they are perfectly
at home.

Propagation. Formerly it was advocated that the best understock
for Japanese cherries was that of the Sargent cherry, Primus Sargenli,
formerly called Primus serrulata sachalinensis .

Mr. William H. Judd, Propagator at the Arnold Arboretum, after
long experience with these plants, now feels that the use of Prunus
avium as an understock is perfectly satisfactory. This understock
4 ‘works” slightly better than that of the Sargent cherry and is cer-
tainly much more easily obtained. It is widely used for this purpose
by many nurserymen. Particular forms of Prunus subhirtella can he
grafted on seedlings of this species. Primus yedoensis may he grown
from cuttings or grafted on P. avium stock. All double-flowered vari-
eties can he grafted on P. avium stock. There are certain species which
can be readily grown from seed, and would include P. Sargenti , P.
incisa, P. nipponica , and often even the hybrid, P. yedoensis although
in this species the plants do not always come true from seed. The
Arboretum wishes to modify certain statements which have been made
in the past in this Bulletin regarding understock for Japanese cherries
and emphatically states that P. avium as an understock has certainly
proved as good if not better than P. Sargenti.

Prunus Sargenti. Introduced about 1890 from seeds sent to the
Arboretum by William S. Bigelow, this fast growing tree has proved
the most hardy of all the Japanese cherries. It is the tallest, being a
fair-sized tree, and is the only one of all the Japanese cherries that
has any autumn color. This is a good deep red. The flowers are deep
pink and single. It is one of the first Japanese cherries to bloom,
usually opening before or at about the same time as the leaves ap-
pear. Because of its size, its hardiness, and its attractiveness in both
spring and fall, this cherry is proving a valuable ornamental and is

PLATE III

Prunus Sargenti (formerly P. serrulata sachalinensis)

This is the largest and hardiest of all the Japanese cherries. It
may be either upright and pyramidal in form (as in foreground) or
considerably more rounded (see other tree at rear of bench) .

deserving of much wider use.

Prunus yedoensis. The Yoshino cherry is another one of the single-
flowered forms and makes up the greatest part of the display at Wash-
ington, since almost half of the original gift from Tokyo was of this
variety. Professor Sargent wrote of this tree in 1922 that it was one
of the favorites in Japan and before the earthquake in that year there
were over 250,000 trees in Tokyo alone. The Sargent cherry is often
upright in habit, but the Yoshino is more spreading. It has pale pink
flowers which sometimes are almost white and can be combined with
the Sargent cherry for general landscape effect, for the flowers of
both open at approximately the same time.

Prunus subhirtella. The Higan cherry is perhaps the most flori-
ferous of all. Its single flowers are borne in the greatest profusion,
and it is not unusual to find the branches literally covered by the
blossoms. There is wide variation in the shapes of individual trees
when grown from seed, but as a rule they are small and of very bushy
habit with pale pink blossoms. All cherries, of course, are used most
effectively in front of an evergreen background of pine or hemlock
wherever such planting is possible.

Perhaps the most common cherry planted now is the drooping form
of the Higan cherry, Prunus subhirtella pendu/a. Another outstanding
form is Prunus subhirtella autumnalis, which often has a second bloom
in the fall though at that season it is not particularly outstanding.
Last spring a large tree of this variety was more attractive than any
of the other cherries in the Arboretum. Its light pink, semi-double
flowers are most outstanding. If the crop of flowers in the spring is
unusually large, then the number of flowers in the fall will be very
small. This tree is another good type and should be used a great deal
more in combination with the early blooming single-flowered types.

FIELD CLASS AT ARBORETUM DURING MAY

A Field Class will be conducted Saturday mornings during May to
assist those who wish to gain a more intimate knowledge of the flower-
ing trees and shrubs growing in the Arnold Arboretum. The class will
meet from 10:00 a.m. to noon, is open to anyone who is interested,
and will meet at the Forest Hills Entrance of the Arnold Arboretum
for the first time on Saturday, May 1.

Registration for the course is one dollar, payable in advance by
mail.

Donald Wyman

[12]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V MAY 7, 1937 Number 3

THE IDENTIFICATION OF PLANT MATERIAL
AT THE ARNOLD ARBORETUM

THERE are many waiys in which the Arnold Arboretum furnishes the public
with information concerning trees and shrubs. One of these is the identifica-
tion of plant material sent through the mail. Most of the work of identifying
plants is done in the herbarium, and it may be interesting and helpful to give
some account of how the work is handled.

When a specimen is received at the Arboretum, it is examined by some mem-
ber of the staff, who may be able to identify it at sight. Some plants are so dis-
tinct and easily recognizable that it may be possible to name them from a single
typical leaf or fruit, but often the problem is not so simple. If the plant is not
readily recognized, the investigator tries to limit it to certain plant families through
such characters as are shown by the specimen, and then proceeds to follow up
clues that may lead to its full identification. This is done by comparing it with
mounted specimens in the herbarium, or, if possible, with living plants, and by
consulting descriptions and illustrations in the literature dealing with the group
to which it is thought to belong. This may involve much library and herbarium
search, and hours may be spent in solving a particularly difficult problem. Some-
times the material received is so inadequate that the investigator must send for a
more typical specimen. However, because of an unwillingness to disappoint the
inquirer and because a difficult problem offers something of a challenge, every ef-
fort is made and every means is exhausted before such a course is taken. In cases
where some doubt may remain after a careful study of the material, the investi-
gator often consults with other members of the staff, especially if the plant be-
longs to a group with which one of his colleagues is especially familiar.

Plants are extremely variable, there often being a wide range of diversity in
various characters even within a single species. Some groups of plants are much
more variable than others. For example, in the roses, apples, plums, hawthorns,
cherries and others, there is such great variability that authorities differ widely
as to their classification. Some recognize numerous species based on slight varia-

[13]

tions while others place these slightly varying forms under a single name. The
leaves of a species may differ greatly in shape and size, not only in different plants,
but even on a single plant; while sometimes flowers, fruits and other parts are
equally variable. Again, the leaves of seedlings, young plants, or those from vig-
orous shoots are very different from those of the mature plant or of typical flow-
ering branches. Some of the divergent forms seem to be due to ecological con-
ditions, such as the character of the soil, or the amount of light, moisture and
shade received. Some of these aberrant forms can be accounted for only as sports
or abnormalities, some as hybrids between related species, and in other cases they
can only be regarded as individual differences, which are common to all living
things. Consequently, when branches are selected for identification they should
be taken from a normal plant. They should be fully matured in growth, but not
have reached maturity too fast, due to excessive vigor, or too slowly, due to poor
growth conditions, insector disease troubles. If normally matured typical branches
are selected, the inquirer will go a long way in assisting the Arboretum staff to
correctly identify specimens.

A vast amount of literature has been written about plants, and this is being
increased each year by students of various groups in all parts of the world. That
the subject of plant classification is one regarding which the last word has not
been said is shown by the fact that for the higher groups of plants alone about
6500 new binomials are published each year, of which approximately 4750 rep-
resent species supposed by their sponsors to represent previously unnamed and
undescribed ones. Furthermore, many groups are subject to constant study and
revision. Good manuals, covering the floras of most parts of the United States
have been published and many other reference books about both native and cul-
tivated plants are available. Some of these books are fully illustrated and contain
keys and descriptions that make them valuable and almost indispensable to serious
students of plant life. However, the information they contain is limited, because
of the great number of species considered, and it is impossible to include in them
more than brief descriptions, these usually limited to the typical forms. In any
event, when a specimen comes to the Arboretum for identification, the investigator
is familiar with these various sources of information, and thanks to the excellent
library facilities available, he can turn to the desired references immediately.

Suggestions for shipping

In sending material for identification, a few simple rules, if observed, may save
disappointment to the inquirer as well as much time and trouble to the Arbore-
tum staff. For the identification of trees or shrubs a small branch should be sent
which bears flowers or fruit, as well as typical leaves. The specimen may either
be pressed and mailed dry between cardboards, or if the material is not too frag-
ile or the distance too great, it may be sent fresh. Fresh specimens may be placed
between paper and cardboards or packed in waxed or slightly dampened paper
and either mailed in a carton or protected by heavy wrapping paper. When more
than one specimen is sent, each should have a number attached to it, and a list
should be sent with corresponding numbers, giving as much information as pos-

sible about the plant. In doing this, the same numbers should be given to the
plants from which the specimens were taken. Large fruits, not attached to the
branches, may be wrapped separately and should also bear the same number as
the leaf specimen to which they belong. It should be indicated whether the plant
is a tree, shrub or vine, the approximate height and general habit or shape, also
whether it was found wild or in cultivation; if from cultivated plants, the source
of the plant or seed should be indicated if known. It is also helpful to give the
popular or local name, if known, and to state the color of the flowers which may
be too much faded when they arrive for this to be determined.

In the case of crab apples and similar plants represented in gardens by nu-
merous hybrid forms, both flowers and fruits are often necessary for identifica-
tion ; herbarium specimens of both stages from the same plant, or herbarium
specimens of one and fresh specimens of the other should be sent at the same
time. With thousands of specimens sent each year for identification, it is mani-
festly impossible to preserve the specimens sent and keep track of corresponding
specimens received at different seasons of the year.

However, it is not always possible to send samples of flower and fruit of de-
ciduous plants. In some cases, particularly with the general run of nursery stock,
accurate identification can be made without these aides, but in most cases they
are necessary. For instance, it is comparatively easy to identify a normal twig of
a crab apple, but with a few exceptions, almost impossible to tell the exact va-
riety without the flowers or fruit or both. The inquirer should keep these points
in mind and not expect the impossible where flowers and fruits are not sent.

Many of the evergreens however, cannot be readily distinguished without
cones, if at all, and thus cones should always be sent if possible. Some cultivated
forms and varieties are distinguished solely by the shape or habit of the plant,
and can thus be recognized only if information about these characters be given.
In some cases it is necessary to have mature acorns or nuts in order to distinguish
between different species or varieties of hickories and oaks, and both flowers and
fruit may be necessary before some species of plums, apples and haws can be
determined.

The inquirer sending a plant for identification naturally desires to learn a
definite name for it, and in the great majority of cases, it is possible to give this
information if the material received is at all adequate or typical. Sometimes, be-
cause of meager, incomplete, or poorly preserved specimens, identification is im-
possible. In some cases, even though the material is ample, only approximate
identification is possible, because the specimen may not be typical and may differ
in some character from the species to which it seems most closely related. This
anyone who has had considerable experience in studying plants readily under-
stands but to the inexperienced, it is sometimes difficult to explain why definite
identification of the species, variety or form is not always possible.

The material received for identification at the Arboretum ranges from a single
specimen, sometimes unfortunately consisting only of a detached leaf or fruit, to
collections numbering hundreds of specimens. Occasionally seeds, sterile twigs,
resins, gums, and specimens of wood are submitted for identification. Many speci-

[15]

mens of herbaceous plants are sent to the Arboretum, although our living and
reference collections are limited to woody material. Occasionally even mosses,
lichens, and fungi are sent to us from friends who seem to have too great confi-
dence in our stock of information. These may be referred to other departments
of the University, such as the Gray Herbarium in case of herbaceous species,
and to the Farlow Herbarium for cryptogamic plants.

The correspondents who call upon the Arboretum for information range from
professors of botany in leading educational and scientific institutions to persons
with little or no knowledge of plants. The Arboretum is also often called upon
for advice by commercial concerns and by importers of various commodities, uti-
lized in industry. Occasionally, we have been asked to furnish evidence to be
used in litigation, or even to settle a wager. During the height of the cross-word
puzzle craze, numerous inquiries were received, most of them by telephone, re-
garding the name of some tree or other plant with vaguely described characters
but containing a definite number of letters. After a few good-natured efforts to
comply with these requests it was decided that this was not really part of our
mission in the world.

There are no fixed formulas for identifying plants, nor does the scientist pos-
sess any occult powers for distinguishing them. All that the investigator can do
is to examine the material available, noting the characters shown, and try to place
it in its proper relationship in view of what he knows about plant classification
and the characteristics that distinguish plant families, genera and species. Only
when good material is supplied can the determination be made with facility and
certainty.

The botanist is not infallible and he is not dealing with an exact science. If
he is honest, he will sometimes have to express a doubt, or admit that he does
not know, and at times he may make mistakes. As an illustration of the difficulty
found in some groups of plants, a botanist in one of the western states, in study-
ing the plants of his region, found a number of specimens of wild roses that were
difficult to classify, and some of these were sent to other botanists for study. In
one case he reports sending identical specimens from the same plant to four of
the leading botanical institutions of America, and of receiving in reply four dif-
ferent opinions as to the identity of the plant. Being himself a botanist and re-
alizing some of the difficulties involved, he did not, as a result, completely lose
confidence in the institutions nor in the value of the opinions of the man con-
nected with them ; at least he is still sending puzzling specimens to the Arbo-
retum for determination.

From the appreciative letters received from correspondents who have called
upon us for help, we believe that the service the Arboretum is rendering in plant
identification is a useful one. We wish to make the service as efficient as possible
and to answer all inquiries as promptly and as fully as we can. It is hoped that
this explanation of the methods followed and of the limitations of the service
may be mutually advantageous to our correspondents and to the Arboretum.

Ernest J. Palmer

[10]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

MAY 14, 1937

Number 4

Series 4. Vol. V

TWO MONTHS OF AZALEA BLOOM

AZALEAS form a most colorful display of bloom in the springtime,
and if care is taken in selecting certain species it is possible to
obtain a flowering sequence for a period of over two months. Many
azaleas commonly grown in the south are not hardy in the northeastern

United States, but all are valued for their bright flowers and some for
their fragrance. The foliage of some deciduous azaleas turns a brilliant

red in the fall, and such forms certainly warrant more extensive use.
The more plants of twofold interest that we can use in our gardens,
the longer our gardens will be enjoyed.

What are the differences between rhododendrons and azaleas?
Now that azaleas are classed in the genus Rhododendron , this forms a
perplexing problem to many, but is well clarified by a recent state-
ment made by Professor Alfred Rehder: 4 ‘There are no clear cut
characters between rhododendrons and azaleas ; they can only be sep-
arated by a combination of characters. Rhododendrons are all ever-
green except R.mucronulatum and R.dauricum but there is an evergreen
variety of the latter : they have mostly ten or sometimes more stamens,
and the leaves are often scaly or lepidote ; azaleas are mostly decidu-
ous ; they have mostly five stamens, the leaves are never dotted with
scales and are often strigose. The two deciduous rhododendrons are
distinguished from all azaleas by the leaves being dotted beneath with
minute scales and also from most of them by the ten stamens.”

As with rhododendrons, all azaleas need acid soil. This is not the
only soil requirement, for it is usually best to keep their roots cool
and moist all the time. This is best done by applying a good mulch,
such as well-rotted oak leaves, pine needles, or acid peat moss.

Although there are a large number of excellent hybrid azaleas a-

vailable in the trade today, it is the object in this bulletin to discuss
briefly only certain species which are known to bloom in sequence, so
that by selecting plants from this list it may be possible to have azalea
flowers in the garden for eight or ten weeks.

ORDER OF BLOOM

Late April

Rhododendron mucronulatum
Early May

Rhododendron obtusum amoenum
Rhododendron obtusum arnoldianum
Rhododendron obtusum ’ ‘Hinodegiri’*
Rhododendron mucronatum

Mid May

Rhododendron canadense
Rhododendron obtusum Kaempferi
Rhododendron yedoense poukhanense
Rhododendron Schlippenbachii
Rhododendron Vaseyi
Late May

Rhododendron atlanticum
Rhododendron japonicum
Rhododendron nudiflorum
Rhododendron roseum

Early June

Rhododendron calendulaeeum

Late June

Rhododendron arborescens

Early June

Rhododendron viscosum

Korean Rhododendron

Amoena Azalea

Hinodegiri Azalea
Snow Azalea

Rhodora
Torch Azalea
Korean Azalea
Royal Azalea
Pinkshell Azalea

Coast Azalea
Japanese Azalea
Pinxterbloom
Downy Pinxterbloom

Flame Azalea

Sweet Azalea

Swamp Azalea

Rhododendron mucronulatum (sometimes incorrectly called Azalea
mucronulata) : This was originally introduced into America by the
Arnold Arboretum in 1882 and blooms before any of the azaleas. It
is the only true rhododendron discussed in this Bulletin and is one of
the two deciduous rhododendrons. The flowers are large and rosy
purple. If the weather remains cool, it may hold its beautiful flowers
for about two weeks. Sometimes late frosts kill the flowers after they
have opened, but if it is planted in the shade and protected from the
morning sun the chances are increased for its remaining in good con-
dition for some time. Most of the early blooming shrubs have yellow
flowers in the early spring, but here is one with a rosy purple color

[18]

PLATE IV

Pink-flowered Rhododendron Sch/ippenbachii

which makes it very conspicuous.

Rhododendron canadens e( Rhodora canadensis) : The Rhodora grows
all over New England and southeastern Canada where it covers large
areas of many acres. It has small flowers of magenta-rose or lilac to
nearly white in color. It likes moist swampy areas where it is per-
fectly at home. It grows about 1 to 3 feet tall and is perhaps the least
ornamental of all North American azaleas although it is admired by
many and used considerably in naturalistic plantings.

Rhododendron mucronatum ( Azalea mucronata , A.ledifolia alba , A.
indica alba ) : Unfortunately, this lovely white flowering azalea, al-
though perfectly hardy from Long Island southward, is not completely
hardy in New Pmgland gardens. Still it can be grown in shaded and
protected situations. There are excellent plants doing well in gardens
on Cape Cod. This lovely plant, so highly valued for its white flow-
ers, has been in this country for almost one hundred years. It is one
of the best azaleas for pure white flowers, it roots readily from cut-
tings, and forms a dense flat-topped mass of foliage that faces to the
ground on all sides. Where it can be well grown, it is an excellent
plant to use in combination with such bright colored species as R.
obtusum Kaempferi, for although it blooms slightly earlier, the flowers
remain on the plant long enough to make a striking color combination
with the later blooming torch azalea.

Rhododendron obtusum: Neither R.obtusu?n amoenum ( Azalea amoe-
na) nor R. obtusum 44 Hinodegiri” ( A.Hinodegiri ) are completely hardy
in Boston. The former is probably hardier than any other evergreen
azalea, but its flowers are a very poor magenta color that is extremely
hard to use in combination with any other color. On the other hand,
R. obtusum 44 Hinodegiri” has decidedly better flowers and foliage, but
it is not quite as hardy. The foliage of both of these plants is superior
to that of R. mucronatum. In some places R. obtusum amoenum is used
as a clipped hedge, because of its very small leaves and also because
it stands clipping very well. Rhododendron obtusum arnoldianum (var.
amoenum X var. Kaempferi ) is similar to var. amoenum, except that it
grows taller and is hardier, being hardy in the Arboretum, and the
flowers are a deep rosy mauve to red. It originated in the Arboretum
as a seedling in 1910, and can be substituted for var. amoenum where
this is not hardy. Rhododendron obtusum Kaempferi , the torch azalea,
is the common mountain azalea of Japan. Although it had been known
for a very long time, it first appeared in the United States when Pro-
fessor Sargent brought seeds to the Arnold Arboretum in 1892. Since
that time it has grown splendidly and has proved to be the best bright

[20]

PLATE V

Rhododendron yedoense poukhanense

Raised in the Arnold Arboretum from seed collected on Poukhan, Korea, in
1905 by J. G. Jack. ( Drawing by Blanche Ames Ames)

red azalea for northern gardens. The Arnold Arboretum now has hun-
dreds of these plants on its hillsides, and when they are in bloom they
make a better display than any other azalea. In places the woods
look almost as if they were afire, the color is so vivid. Because the
flowers may be injured by the hot sun, it is advisable to plant them
in shaded places, and they do well even in complete shade. In the
Arboretum some of the plants are considerably over 5 feet tall, and
they may eventually attain a height of 10 to 12 feet, with a corres-
pondingly broad spread.

In Massachusetts the plants are partly deciduous, but further south
the leaves of R. obtusum varieties (except var. Kaempferi which is
wholly deciduous) are retained throughout the winter. The flowers
of var. Kaempferi range in color from salmon to a brick red. When the
plants are massed together, as is often best in order to afford some
protection to the roots, they make a dense mass of foliage and flowers
and form one of the best displays of Japanese plants growing in the
Arboretum.

Rhododendron yedoense poukhanense ( A .poukhanense) : Originally
named by a French botanist from Mt. Poukhan in Korea, where the
plant was discovered for the first time by a French missionary, this
plant was introduced into this country by Professor J.G.Jack of the
Arnold Arboretum in 1905. The flowers are a pale lilac-purple and
are usually borne in great profusion. The plant itself rarely grows
taller than about 3 feet and is thus well suited for rock gardens and
small borders. The branches grow close to the ground making a dense
mass. In using it in combination with other flowering plants, its color
should always be kept in mind for this proves rather difficult to com-
bine well with red. There is a double-flowered variety available called
“Yodogawa,” but it is more tender.

Rhododendron Schlippenbachii ( A.Schlippenbachii ) : This is another
Korean plant much used in that country, introduced by the Arnold
Arboretum from seed sent by Professor Jack. The flowers are very
large, sometimes as much as 3 inches in diameter, and a pale to rosy
pink. Apparently perfectly hardy under New England conditions,
this plant may grow to be 15 feet tall. One of its valued characteris-
tics is the fact that in the fall the leaves turn from yellow to orange
crimson, thus enabling landscape gardeners to utilize it for autumn
as well as spring color.

Rhododendron Vaseyi (A. Vaseyi ) : This is the second of the native
American azaleas to bloom in the spring. It is found in a few valleys
of the southern Appalachian mountains, chiefly in South Carolina

where it grows to be 15 feet tall. The flowers appear before the leaves
and are a good pink color. It is perfectly hardy in Boston and is
highly valued for its delicate flowers, which are very conspicuous be-
cause they appear before the leaves.

Rhododendron japonicum (A . japonica) : The large orange-red flow-
ers of the Japanese azalea are particularly outstanding, but unfortu-
nately they have a most disagreeable odor. The plant is valued for
its large flowers and its hardiness. Because it is perfectly hardy under
New England conditions, it is used considerably in breeding work.
During late May, there are a large number of multi-colored azaleas
that bloom in great profusion, and many of these are hybrids of this
Japanese azalea. Of these hybrids there are two general groups:

1. Rhododendron gandavense: The Ghent azaleas are very popular
and many interesting forms are available. These result from crosses
between the tender, fragrant, yellow-flowered R. luteum (A. pontica)
the American R.calendulaceum, and R. nudiflorum. The colors in these
hybrids are all shades and combinations of those of the parent plants.

2. Rhododendron Kosterianum : The * 4 Mollis” hybrids are the result
of a cross between R.molle , which is tender here in the north, and
R. japonicum. Mr. T. D. Hatfield’s original hybrid named 4<Miss Louisa
H unnewell” is an outstanding example of this group.

Rhododendron nudiflorum {A. nudiflorum) : All the azaleas bloom-
ing after June first are natives of this country. The common pinxter-
bloom is a familiar sight everywhere, for it is native over wide areas
of the eastern United States.

Rhododendron roseum (A. rosea, A.nudiflora rosea) : Another New
England plant, this is probably the best of the azaleas native to this
general region. Its flowers are a deep rosy pink, and most fragrant.

Rhododendron atlanticum ( Azalea atlantica ) : This little azalea is
native on the Coastal Plain from southern Pennsylvania to South
Carolina. It seldom gets over 18 inches tall and can be considered
the smallest of all the azaleas here mentioned. Its flowers normally
are white (there are pink forms) fragrant and about the size of the
flowers of Rhododendron nudiflorum. It is considered as hardy as R.
obtusum Kaempferi , does well in the Arboretum and is an excellent
little plant to use, particularly in small scale plantings. It does eqully
well in both sun and shade, and is good for filling in around the bases
of taller growing azaleas when this is necessary.

Rhododendron calendulaceum ( A .calendulacea) : The flowers of the
flame azalea are usually a brilliant orange red, but lack the fragrance
of the two preceding species. It occurs in the mountains from Penn-

sylvania south to Georgia, and is very abundant on the lower slopes
of the high mountains of North Carolina and Tennessee. It is the most
showy of the American azaleas which have been established in the
Arnold Arboretum. It is perfectly hardy and superior to most of the
hybrids derived from it. One of its best features is the fact that its
flowers remain in good condition for a considerably longer period than
do those of the Asiatic azaleas, for they are not injured by excessive
heat.

Rhododendron arborescens (A. arborescens) : Since the flowers of
this azalea do not appear until after the leaves are fully grown, it is
not as conspicuous as some of the others, but it is very fragrant. The
white or slightly pink flowers are of interest because of their fragrance
and also because of the long red stamens. At high elevations it only
grows a few feet tall, while in valleys in the mountainous regions
where it is at home it may grow to be 18 feet tall. It is another na-
tive of the Appalachian mountains.

Rhododendron viscosum ( A.viscosa ): This is a common plant in
swampy regions in the northeastern United States and is valued be-
cause it is the last of all the azaleas to bloom. Its flowers are usually
pure white and most fragrant. Strangely enough, in spite of its nat-
ural habitat, it does not require swampy conditions, as it will thrive
in almost any fertile acid soil.

Horticultural Society Field Day

The Massachusetts Horticultural Society will hold a Field Day at
the Arnold Arboretum on Thursday, May 20 at 2 P.M. to discuss and
inspect the lilacs. If rainy the meeting will be postponed until the
next day. The group will meet promptly at the Administration Build-
ing of the Arboretum. After a short discussion a careful inspection of
the lilac collection will be made.

The lilacs will be in full bloom the week end of May 22. This large
collection at the Arboretum is unusually well budded this year and the
display of flowers should be most outstanding during the current week.

Donald Wyman

[•24]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V MAY 21, 1937 Number 5

THE CHINESE COLLECTION

ONE of the most striking portions of the Arnold Arboretum during
May and early June is the varied collection of shrubs and trees
planted on a rounded knoll just southeast of the summit of Bussey
Hill. Gently curving grass paths encircle the crown of this knoll,
with branches leading off down the slopes in different directions.

Two of these paths lead off from Bussey Hill Road opposite the
banked plantation of forsythia which has produced such a wealth of
color this spring. At the points from which they take off the paths
are margined with tall vacciniums, barberries and calicarpas. One goes
only a short distance before he is confronted with a splash of brilliant
yellow in the plantings of cytisus and genista which lie between the
paths. To the right is the nearly pure white Rhododendron Schlippen-
bachii which has the largest flowers of any of the azaleas in the collec-
tion. From here on there is a profusion of color and form. A mound
of lilac-purple blossoms nearly conceals a massed planting of the Ko-
rean azalea ( Rhododendron yedoense var. poukhanense ) . Under the old
pines are the early-flowering Rhododendron mucronulatum , various forms
of Enkianthus with their delicate pendulous blossoms, and the brilliant
Rhododendron obtusum var. Kaempferi. Farther down the slope to the
southward are beds of the hybrid azaleas in whose flowers a variety
of salmon-pink tints play havoc with our usual concepts of color in
this group. The dove-tree ( Davidia involucrata) is represented in sev-
eral places along the upper paths. It was killed back to the ground
during the recent hard winters, but now shows vigorous sprouts six
to eight feet high. Fothergilla , Leucothoe , Stewartia, and many forms
of Cotoneaster are arranged in the beds above the pines, as well as the
exotic maples (Acer Tschonoskii , A. griseum) and Euptelea.

In large beds around the crown of the hill, inside the paths, are
barberries, honeysuckles, cotoneasters, hydrangeas, Kerria and Acan-

thoparuu. Near the point where the largest of the paths returns to
Bussey Hill Road is a large plant of Exochorda , the pearl bush. The
top of the knoll itself has an open plantation of flowering cherries,
crab apples, barberries, and honeysuckles.

On the south side of the knoll, rising from the midst of an exten-
sive planting of azaleas, are some ancient white oaks. They are much
the largest and oldest trees in the Arboretum. In 1931 the lightning
killed one of these veterans and it was immediately cut down, show-
ing a trunk which had resisted disease so successfully that it was solid
to the center. It proved to be about 265 years old, so that its life span
covered most of the period since the first hardy settlers took up land
in the Town of Roxbury. It was a young spindling shoot in the 1670’s
and during the first 90 years of its life it attained a diameter of only
6 inches. This can indicate that it grew until about 1750 or ’60 in a
rather dense woodland of trees so large that they kept it in shade.
At about this stage in its life, however, the surrounding remnant of
the primeval forest in which it stood was nearly all cut down. The
result was that, relieved of competition with its older neighbors and
exposed to full sunlight, it acquired a new lease on life. From that
time on it grew rapidly, putting on thick rings of wood each year.

It is intriguing to reconstruct the scenes which have passed upon
this knoll during the lifetime of the old oaks. Several generations of
the children of the Weld families that lived on the property must have
played among the great columnar trunks of that small patch of prim-
eval woods which persisted for at least half a century in the otherwise
cleared pastures and orchards of the district. Hepaticas, columbines
and asters must have made a garden of the shaded aisles. In Revolu-
tionary times when firewood was scarce in Roxbury, the stunted rem-
nants of the old wood were too small or too inaccessible to be attractive.
Or perhaps they were purposely preserved by some Weld descendant
to keep alive childhood memories.

In the first decade of the 19th century Mr. Benjamin Bussey, a
well-to-do Boston merchant, realized the beauty of the site and pur-
chased the farm containing it for a country home to which he could
retire in his declining years. He built his mansion on the easterly
side of what we now call Bussey Hill, and a summerhouse at the top
of the slope. A double row of white pines was planted in rectangular
arrangement around the crown of the hill, and long rows of lilac bushes
margined the paths which led up to the summerhouse. Several of the
pines are still standing: and though somewhat broken in appearance
and bent to the eastward by the winds, they contribute much to the
beauty of the modern plantations. The rows of lilacs, large parts of
which also remain after at least 125 years, have grown together so
that the old paths are scarcely visible. To the westward were views
of pasture and orchard, in fields separated by the characteristic stone

PLATE VI

Part of the Chinese Collection on the top of Bussey Hill
in the Arnold Arboretum

walls which lend charm and order to so much of the New England
landscape. Northeastward were Jamaica Plain and Roxbury, and on
clear days the Bay was visible. Southeastward one could look across
the valley of Stony Brook to Milton and the Blue Hills. From the
time of the changes wrought by Mr. Bussey the top of the hill has
remained a garden spot. At his death about the middle of the last
century, he left it to Harvard College as part of a foundation for a
school of agriculture and horticulture. Subsequently Frederick Law
Olmstead, pioneer in American landscape architecture, planning the
Arnold Arboretum with Professor Sargent, clearly recognized its at-
tractiveness and potentialities. Bussey Hill Road, made to encircle
the hill and end in a broad plaza on the summit, gave easy access to
the whole area and ensured its significance as a focal point in future
developments.

The plantings as we know them now did not take form until about
25 years ago when the collection of the late E. H. Wilson began to
appear at the Arboretum. Our rounded knoll was selected as a suit-
able place for a special exhibit of floral wonders introduced by this
gifted gentleman, and the whole area became known as “the Chinese
collection.” An old photograph in the library of the Arboretum shows
that early in the 1900’s the knoll was a grassy meadow from which
hay was cut in summer. Its soil is gravelly and poor, and the long
struggle to make it suitable for planting can only be visualized from
Professor Sargent’s cryptic records in his annual reports and from the
recollections of men still at the Arboretum. At one time, for instance,
masses of peat cut from the low ground of the South Street tract were
strewn over the beds to increase their fertility.

The old oaks have seen the whole gamut of change. They served
as part of the background for the long years of toil and struggle en-
dured by the colonial farmers who built their successful communities
in the New World. Forces which began to be felt through the ambi-
tion and imagination of Mr. Bussey finally brought the land into con-
tact with a great educational enterprise so that it contributed its small
part to the vast influence upon American applied biology which the
Bussey Institution exerted. But the later scenes are the strangest.
Here are exotic plants brought from the other side of the world to be
tested for beauty and adaptability before they can be used to grace
American gardens : azaleas with giant, pure white flowers entirely un-
known in America; other azaleas with almost every conceivable com-
bination of red, orange, white and purple; the curious dove-tree with
flowers like great white wings ; and impossible maples with copper-
colored bark that peels off in thin sheets like that of the sycamore.
Such wonders were certainly beyond the wildest dreams of those
children of the Welds’ who played here. The only continuity is in
the inherent charm of the place and in the lives of the ancient oaks.

H UGH M. Raup

[28]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V MAY 28, 1937 Number 6

A TRIP THROUGH THE ARBORETUM DURING LILAC TIME

THOUSANDS of people have had the opportunity of visiting the Arboretum
during the past ten days, and they have been fortunate for the Arboretum
is now at its best. This Bulletin is written in order to aid our many visitors in
remembering a few of the many things they have seen in bloom. Perhaps too,
those who have been less fortunate and were unable to visit the plantations dur-
ing this period, may derive some enjoyment from reading this enumeration of
the plants of outstanding beauty which have been admired by so many.

Most of the trees and shrubs at the Arboretum are looking better this year
than they have for several years past, merely because the mild weather has not
injured any of the flower buds. We have been unable to find any evidence of win-
ter injury due to low temperatures. Elsewhere in eastern Massachusetts, partic-
ularly where rock garden plants and perennials are grown, there has been con-
siderable injury owing to lack of snow during last winter from the soil heaving
and exposing the roots of the plants, but fortunately this has not been true of
the trees and shrubs. Many of the azaleas, the flowering dogwood, and the lilacs
have really been exceptionally beautiful during the past ten days because the
flower buds have been untouched by the winter cold and all have fully opened.

Starting the trip through the Arboretum from the Jamaica Plain gate, we
first notice the peculiar green flowers of the native Magnolia acuminata beginning
to bloom. The flowers of the Asiatic magnolias have long since passed. Continuing
on the road from the Administration Building we pass the lindens and an excellent
bed of Rhododendron roseum which has been in full flower for an entire week. A
little farther on, near the horse chestnuts, is a planting of the daintily colored
pinkshell azalea, Rhododendron V aseyi , which adds a bright spot to any landscape
scene. Opposite this are the many forms of the Japanese maples coming out into
full leaf, and the brilliant red of their foliage makes a beautiful contrast with the
white flowering dogwoods close-by. In the woods are several hundred torch aza-
leas, Rhododendron obtusum Kaemjiferi , which have been in full bloom for over a
week, and because of the excellent shade of the surrounding oaks, their flowers

keep their color for a considerably longer period than do those of azaleas planted
out in the full sun.

Leaving the road for a moment, we stroll through these azaleas to a knoll in
the woods overlooking the shrub collection. Approximately a thousand different
shrubs are growing here, and with a hasty glance from our vantage point we no-
tice that there are not many plants in bloom. At the extreme left there is a bright
spot of white close to the ground (Iberia Tenoreana ), and nearby another bright
spot of yellow ( A/yssum gemonense), blooming at the same time, while Iberis sem-
pervirens will not bloom for another week. Looking farther, we see the white of
some spiraeas in bloom, and at the end of the collection the tall pearlbushes in
full bloom. In front of us is a long row of vari-colored varieties of the Japanese
quince, but as these have been in bloom for over two weeks they have now nearly
lost their brilliance.

Beyond the shrub collection, along the road on the farther side we see the
last of Malus spectabilis , one of the double-flowering crab apples, and the first of
the common pink Bechtel’s crab coming into bloom. When the wind changes for
a few minutes, we can immediately identify the fragrance of the bush honey-
suckles which are now in full bloom nearby.

Continuing from the woods interplanted with torch azaleas, we glance back-
ward through the shrubbery overhanging a pond on the left to see an excellent
planting of Rhododendron Vaseyi in full bloom, the dainty shell-pink color of the
flowers reflected in the still water at their feet. Continuing between the ponds
we turn to the right and approach the lilac collection.

What a sight! The bank is one mass of color. In this collection, one of the
two best in the world, are over 400 different kinds of lilacs including over 300
different varieties of Syringa vulgaris alone. A good growing season followed by a
mild winter has resulted in a profuseness of bloom unequaled for several years
past. One of the first plants to draw our attention is the dark purple variety of
Syringa vulgaris named “Ludwig Spaeth. ” We admire it, walk under its branches,
and look up the lilac walk, bordered on both sides with lilacs ten feet tall and
covered with blossoms. We notice at least two lilacs (Syringa amurensis , the Jap-
anese tree lilac, and S.villosa , the late lilac) that are not in bloom, for these come
later, one in July and one in June. Continuing up the walk among the lilacs, we
see the most fragrant of all, S. pubescens, and can easily recognize its value even
though its flowers are not conspicuously colored.

On the left of the walk is the interesting small Persian lilac and its several
varieties. Nearby is S.chinensis, the first known hybrid, resulting from a cross be-
tween S. persica and S. vulgaris. One of its varieties, S. chinensis Saugeana , is par-
ticularly valued for its dark reddish flowers. Both the Persian and the Chinese
lilacs are valued for their profuse, graceful, nodding sprays of flower clusters
which make them among the best for cut flower purposes.

Near the end of the row of lilacs, placed between the walk and the road, are
two plants outstanding for their deep reddish-purple flowers, namely Congo”
and “Negro.” Incidentally, it was this row of lilacs which was cut to the ground
ten years ago in an effort to reduce the size of the plants and so force them to

[30]

grow into better specimens which would be appreciated more. A critical survey
of these same plants today will show that this severe treatment has resulted in
plants which are now in excellent condition. Many people who knew this row of
plants the year it was cut to the ground have remarked this season that although
such rough treatment is not always warranted it has certainly proved worth while
in this case.

On the hill at the extreme end of the lilac collection are the younger lilacs
recently added. One of these shows promise of becoming the darkest of all the
dark lilacs. This is named “Mrs. W. E. Marshall” and is of very recent origin.
Man}’ of these lilacs are so intriguing that it is necessary to walk over the grassy
path at the top of the collection and see close at hand some of the plants that we
could only glimpse from below. One of these is a stunning single white variety
named Vestale” which is unusually well-flowered this year. Another variety close
by is the double-flowered “Edith Cavell” also outstanding for its white flowers.

Of the pink varieties, “Macrostachya,” “Lucie Baltet,”and “Clara Cochet”
can all be observed in order, one after the other, growing along this path. Farther
along on the right we must stop to admire the best of the pale blue lilacs, “Presi-
dent Lincoln,” the flowers of which are a wedgewood blue. It is most difficult
among so many fine specimens to decide definitely on a few “best.” Professor
Sargent use to say that the “best” lilacs were always those that happened to
have the best flowers that year, and perhaps this should be our conclusion.

Climbing up toward the top of Bussey Hill we pass through an old lilac hedge
which is easily one hundred and twenty-five years old. These bushes are seldom
pruned and sprayed, and are living examples of what lilacs will do under adverse
conditions. They are now about ten feet tall (having been cut to the ground sev-
eral years ago) and almost twice as broad, but even with the lack of care they do
have many blooms each year. Atthetopof Bussey Hill in the Chinese Collection
we find many things in full bloom. Our first impression is one of brilliant yellow
color coming from the brooms which are at their best. These belong to the genera
Cytisus and Genista. One plant stands out particularly among these because of its
brilliant mass of profuse lemon-yellow flowers. This is Cytisus praecox, and thbse
who have admired it will be glad to know that it is available from certain nurseries.

To the right of this walk, across from the brooms, we see the last of the royal
azalea, which is one of the first in the collection on the hill to bloom. Over the
brow of the hill we notice many of the torch azaleas dotting the hillside here and
there. Walking on toward the century old pine trees, acting as guardian sentinels
for the entire collection we pass a bed of two beautiful azaleas, Rhododendron ro-
seum and Rhododendron nudiflorum. These came into full bloom on lilac Sunday,
and their sweet fragrance fills the air. Beyond these is the Poukhan azalea, its
lavender-purple flowers fading rapidly for it has been at its best for almost two
weeks. However, one or two of the plants which are late to bloom indicate to us
what the entire planting must have looked like when it was at its best.

We notice that the dove tree, so interesting because of its history, has again
disappointed plant lovers and has not bloomed. This tree was killed to the ground
during the cold winter of 1983-34 and has not bloomed since. Each year we look

forward to seeing its blossoms, but usually we are disappointed. Under the pine
trees are the best plants of the torch azalea in the entire Arboretum. Here some
are at least six to eight feet tall, literally one solid mass of fiery red blossoms. It
is easy to notice the injury from the hot sun for some of the blossoms are badly
faded and burned at the tip of the petals, but when they are growing in the full
shade they keep their color very well for some time.

Continuing down the hill among the azaleas, we come to an excellent group
of Ghent” and Mollis” hybrids on the left, many of which are just beginning
to show their excellent, highly colored blossoms. A number of these are perfectly
hardy under Boston conditions and their wide variety of colors are unequaled by
any other group of shrubs. On the right is the Arnold azalea, a chance hybrid
in the Arboretum, having many of the qualities of Rhododendron obtusum amoenum
but at the same time being considerably more hardy.

Walking toward the old Bussey Mansion we see another planting of the torch
azaleas, where one thousand plants have been placed under protecting pine trees.
Among these are a few dogwoods, and as we gaze on this scene fora few moments
we must admit that unquestionably this torch azalea is the most brilliantly colored
of all the plants we have seen on our trip. In fact, as noted in the Bulletin a few
weeks back, it is the most brilliant of all the bright colored plants introduced to
this country by the Arboretum from Japan. Turning toward the old Bussey Man-
sion, we see its porch covered with wisteria blooms. The common old-fashioned
type, the Chinese wisteria, is at the front and makes the better display, and to-
ward the rear of the house is the lighter colored Japanese wisteria with its longer
flower clusters.

Itetracing our steps for a short distance only, we walk down the hill among
the beeches, admiring the beautiful young foliage of the different varieties, and
now and then glancing toward Hemlock Hill at the base of which the first rhodo-
dendrons are just coming into bloom. Once more on the road at the foot of the
hill some members of the group continue on toward Peter’s Hill and the crab
apples, some walk among the conifers, and others turn to the right and walk back
toward the lilac collection. On our way we walk under an excellent specimen of
the silverbell in full bloom, and a few moments later, off to the left, catch a
glimpse of brilliant white which is, on close inspection, a perfect specimen of
the flowering dogwood, about forty years old, at least twenty-five feet tall, and
literally covered with blossoms from top to bottom. With time getting short, we
hasten back to the lilacs where several in the group wish to spend the last mo-
ments of the trip, making notes and comparisons of these excellent plants to
guide them in making their selections for their own homes. It is just for such
concrete purposes as this that the thousands of plants in the Arboretum are being
continually maintained.

Donald Wyman

[32]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V JUNE 11, 1937 Number 7

THE LIBRARY

WHEN one thinks of the library of the Arnold Arboretum the question
naturally arises what is it? How large is it? What sort of books does it
contain, and who may use it? Is it open to the public?

First, what is it? It is essentially a botanical library rather than a horticul-
tural one, although it contains many horticultural works. While it has been de-
veloped primarily as an adjunct to the study of woody plants, yet it is so catholic
in its scope that books on many allied subjects are to be found in it. It was begun
in 1873 when Professor C. S. Sargent, the Arboretum’s first director, obtained a
few standard works needed in planning the Arboretum and arranging its collec-
tions.

How large is it? It now includes approximately 43,000 bound volumes, 1 8,000
photographs, 12,000 pamphlets and several thousand nursery catalogues, thus
ranking as one of the three or four largest and most important botanical libraries
in America. In 1892 when the library had increased to six thousand volumes
Professor Sargent presented it to Harvard University and until his death in 1927
when it numbered more than 37,000 volumes, it was almost entirely his contri-
bution and that of a few of his friends. Since Professor Sargent’s death, growth
has of necessity been slower, partly because of limited funds. Fortunately through
his foresightedness a large proportion of the older important and rare works were
procured during his life time, a collection the value of which cannot be overesti-
mated, for it could not be duplicated today, containing as it does thousands of
out-of-print works. It is believed to be the largest dendrological library in the
world.

Who may use it and how? It is not a circulating library, but primarily a
reference collection for the use of the Arboretum staff ; however, research workers
and others interested in the study of botany are welcomed to the use of the books
within the building. Inter-library loans are often made to other universities and
to botanical institutions. When loans cannot be made, the library can and does
give much help in other ways; it aids visiting students in looking up needed ma-
terial, and upon request sends out lists of the best books on a certain subject,

verifies references, types short references when the inquirer cannot visit the li-
brary, and while there are no facilities for photostat work at the Arboretum, ar-
ranges to have it done at the standard price for this service.

The photographs, mounted, catalogued and filed in steel cabinets are also
available for consultation. They embrace all the photographs taken by Mr. E.H.
Wilson on his trips of exploration undertaken for the Arboretum in eastern Asia,
Australasia, India and Africa, and many obtained in the botanical gardens visited
by him. A very large number have been acquired by gift, by purchase, and by
the later work of Mr. Wilson and other members of the staff. They include pho-
tographs of trees and shrubs in the Arboretum and of famous trees in New Eng-
land, and are arranged in four groups: photographs of men prominent in the
botanical and horticultural world, famous gardens, single specimens or groups of
specimens, and views taken in the countries explored and in parts of our own
country. Where negatives are in possession of the library prints may be made
for purchase upon request.

The scope of the library. In the words of Professor Sargent, “Particular
attention has been paid to books relating to dendrology, general descriptive
botany, the cultivation of trees, the works of travelers in which appear descrip-
tions of trees and of general features of vegetation, and in obtaining complete
sets of the periodicals in all languages relating to botany, forestry and allied sub-
jects.” Special attention has also been given to acquiring books relating to the
history and cultivation of trees and shrubs valued for their economic products,
such as tea, coffee, cocoa, oranges and their allies, cinchona, olive, and the mul-
berry in its relation to silk, since it seemed highly desirable that an arboretum
library should contain all possible books on woody plants. Works on paleobotany,
plant pathology, physiology and entomology are also included.

The Arboretum takes pride in its comprehensive collections of floras, period-
icals and monographs from nearly every nation of the world, more than thirty-
five languages being represented. Here the student may find nearly every ref-
erence pertinent to his studies. The Russian literature is particularly extensive,
probably equaled in America only in the library of the United States Department
of Agriculture. The works on Chinese and Japanese botany have attracted stu-
dents from China and Japan to study the flora of their own country, as in few
places is there to be found so complete a collection. The books on economic bot-
any have proved of distinct value to various commercial firms.

The Arboretum owns a nearly complete set of the botanical works of the
celebrated Swedish botanist Linnaeus and is fortunate in possessing many of the
original Linnaean dissertations which are usually rare items in reference libraries.
It has also the “Viridarium Cliffortianum,” believed to be the only copy in the
United States, since the one in San Francisco was destroyed in the earthquake
of 1906. For twenty-five years Professor Sargent sought to obtain this small
book, which has, perhaps, more of human interest than intinsic value. Linnaeus,
whose Species plantarum,” 17J3, revolutionized botanical nomenclature, and
from which all botanical nomenclature of today dates, was sent to the University
of Lund in 1727 to study medicine. Here his inclination for natural history was

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PLATE VII

Title-page of JarquiiTs “Seleotarum stirpium amerieanarum historia” (cir. IT

favored by Professor Strobaeus, and lie passed three years, 1735-1738, in the
house of George Clilfort, a rich Dutch gentleman living between Leyden and
Haarlem, who employed him to arrange his fine gardens and museum. It was
out of a desire to express his gratitude to his benefactor that he honored his
memory by a work entitled, “Hortus Cliffortianus,” of which the “Viridarium”
is an abridgement.

The collection of Pre-Linnean books comprises more than 1600 volumes.
These are the greatest bibliographical treasures in the library, twenty-six items
falling into the group “incunabula” (cradle books), printed before 1500 when
printing was in its infancy. Of these “cradle books” the first acquired by the
Arboretum was Opus ruralium commodorum” by Piero Crescenzi, a book on
agriculture; the date is unknown, but was probably soon after 1471. Written be-
fore the art of printing was developed, it was, because of its importance, one of
the first to be put upon the press. Konrad von Megenberg, “Das puch der natur,”
1475, is our earliest and perhaps our most valuable work. A later edition of 4 Das
puch der natur,” 1478; Apuleius Platonicus (or Barbarus), “Herbarium,” 1484;
Columella, “De cultura hortorum,” 1480? and Columella, “Hortuli commentari-
um,” 1488-90? are not known to be in any other library in this country.

Other incunabula include Barbaro, “Castigationes Plinii,” 1492-93; Bar-
tholomaeus Anglicus, De proprietatibus rerum,” 1480 and 1491 ; “Libri de re
rustica,” n. d. ; “Herbolarium seu de virtutibus herbarum,” 1491 ; “Ortus san-
itatus,” 1490 or 1497, 1496 or 1487, and 1491; “Gart der gesundheit,” 1485;
Macer Floridus, “De viribus herbarum,” date unknown; “Opera agricolatio-
num,” 1482 and 1496; Matthaeus Sylvaticus, "‘Liber pandectarum medicine,”
cir. 1470 and 1480; Plinius Secundus, “Historia naturalis,” 1483 and 1496;
Theophrastus Eresios, “De historia plantarum,” 148-?; Vincentius Bellovacen-
sis. Speculum naturale,” 2 vol. 1479?, and 3 vol. I486?; and Lucretius, De
rerum natura,” I486.*

Many editions of these fifteenth century books were published in the six-
teenth, seventeenth and eighteenth centuries, and it has been the practice of the
library to obtain as many editions of them as possible. It has, therefore, eight
editions of Macer Floridus, 1506-1588, with one of 1832; three of Columella’s
Husbandry, 1551-1745, with one of 1824; seven of Pliny’s “Historia naturalis,”
1507-1685, with one of 1855-57 ; sixteen of Theophrastus, 1529-1644, and later,
and nine of Crescentius’ “Opus,” 1534-1745, with one 18 — ? Of Prospero Al-
pino there are ten titles and editions, 1592-1745 ; five editions of Francis Bacon’s
“Sylva sylvarum,” 1627-1670; seven of Bauhin*s “Pinax theatri botanici,”
1596-1671 ; nine of Bonnefon’s Jardinier fran^ois,” 1653-1684; seven of Van
Oosten’s Nederlandse bloemhof,” 1700-1749; twenty-one titles and editions of
Richard Bradley on husbandry and gardening, 1716-1757; Brunfels’ Herbarum
vivae eicones,” of 1530 and 1532, and editions 1532 and 1536 of a second vol-
ume; numerous titles and editions by Charles Estienne, 1537-1622; fourteen
works and editions by Olfert Dapper, 1668-1703; full collections of the works of

^A fuller description of the incunabula in the library is given in the Arboretum Journal, vol.
iv. pp. 56-60. 1923.

[36]

Dioscorides, Mattioli, Ray, Evelyn’s “Sylva,” Miller’s “Gardener’s dictionary”
and other gardening books ; twenty-one editions of Dodoens’ Cruydeboeek* * and
other works, 1521-1644; twenty-five works and editions by Leonhard Fuchs’
1531-1572; nine of Herrera’s “Obra de agricultura,” 1513-1608, and 1819;
eleven of Huerto, 1567-1616; sixteen of La Quintinye’s “instruction pour les
jardins fruitiers,” 1690-1756 ; eleven of Liger’s “jardinier fleuriste,” 1706-1792 ;
six of Tabernaemontanus’ “Eicones plantarum,” 1588-1731; Ptolemy’s “Geo-
graphia,” 1562; four editions of Manwood’s Treatise and discourse of the lawes
of the forest,” 1598, 1616, 1665, 1717, and Aristoteles’ “ Problemata quae ad
stirpium genus & oleracea pertinent,” 1539. A fine opportunity is thus afforded
for the comparison of different issues.

Other books in this group of more than usual interest are Boym’s “Flora
sinensis,” 1556, the first book on Chinese botany published in Europe; Bock’s
“Kreiiterbuch,” 1546; Hernandez, “Nova plantarum. . . . mexicanorum histo-
ria,” 1651, the first natural history of the New World; Blake’s “Compleat
gardener’s practice,” 1664; Gerard’s Herbal,” 1597, containing a manuscript
note dating from the time of Shakespeare ; “Le grant herbier,” cir. 1520; “The
greate herball,” 1561, and many others. Many of these books are curiously or
beautifully bound, and very rare.

The two folios of Dioscorides’ “Codex” (l905) in heavy board covers repro-
duce in facsimile the pages and plates of the famous “Codex” prepared in 512
A.D. for the Princess Anicia Juliana, daughter of the Emperor of the Eastern
Empire, which is now preserved in the Hofbibliotek at Vienna. The original is
the oldest known manuscript of a botanical work. It was written in the first cen-
tury of the Christian era. For sixteen centuries this book was considered the
highest medical and botanical authority, and was the precursor of modern treatises
on botany. There are in the library fourteen editions of works by this Greek
botanist.

The period immediately following the 15th century produced many books of
special interest which also are to be found in the Arboretum library. Among
these are Wagenheim’s “Beschreibung einiger nordamerikanischen Holz und
Buscharten,” 1781, the first book on American trees by a German ; Belon’s De
arboribus coniferis,” 1553, the first book on conifers ; a copy of Humphrey Mar-
shall’s “Arbustrum americanum,” 1785, the first book on American trees written
by an American. The most valuable work of Jacquin, an Austrian botanist, is his
“Selectarum stirpium americanarum historia,” cir. 1780, with hand colored plates.
But eighteen (according to some authorities twelve) copies of this work were is-
sued and at the time the Arboretum copy was obtained it was the only one in
this country; there are now copies in the library of the New York Botanical
Garden and in the Congressional Library in Washington.

A large group of books on roses numbers among its items several of outstand-
ing interest. The earliest work, now very rare, is “Collection of Roses from Na-
ture,” by Mary Lawrance, published in London in 1799. There are, with the
frontispiece, ninety-one exquisite plates apparently colored by hand. The only
other copy known to be in this country is in the New York Public Library. Little

is known of Miss Lawrance except that she was a teacher of drawing, but her
book, the first entirely devoted to the rose, will remain always one of the most
interesting. In 1802? appeared the second monograph on the rose, “Die Rosen”
by K.G.Rossig, published in Leipzig and having fifty colored plates. The Arbo-
retum copy was purchased at the Castlecraig sale in England. H. C. Andrews’
“Roses,” 2 vols. 1805-28, also with colored plates, is the third of these early
monographs and is apparently rare. Two editions of Redoute’s “Roses” and all
other works known to have been illustrated by this famous artist are among the
Arboretum’s treasured possessions. A recent work on the queen of flowers” is
the beautiful two volume Genus Rosa” by Ellen Willmott, with exquisite col-
ored drawings by Alfred Parsons, 1914.

There are 182 shelves filled with works devoted to the study of special fami-
lies and genera, 36 to economic botany, 21 to medical botany and several to
cryptogamic botany.

Of the hundreds of illustrated folios, many of them exceedingly rare and
exquisitely illustrated, some have already been mentioned, a few others may be
especially noted : Redoute,“Les Liliacees,” 1802-16, and “Choix des plus belles
fleurs,” 1827; Millais’ “Rhododendrons,” in two series, 1917 and 1924; two
editions of Lambert’s “Genus Pinus,” 1803-37 and 1828; Martius “Flora bra-
siliensis,” 1840-96; Duhamel du Monceau, “Traite des arbres et arbustes,”
(1800-19); Bonelli, “Hortus romanus,” 1772-93; Humboldt, Bonpland, and
Kunth, “Nova genera et species plantarum,” 1815-25; Sibthorp, “Flora grae-
ca,” 1806-40; Curtis, Flora londinensis, ” 1777-98; Oeder, Flora danica,”
1761-83; Riocreux, [Collection of 87 original water color botanical drawings],
bound in crushed Levant, beautifully tooled, no date; and Palisot de Beauvois’
“Flore d'Oware et de Benin en Afrique,” 1 804-07-[2 1 ], excessively rare, the
second volume being one of the scarcest botanical works in existence.

A work in seven volumes of very special interest is 4 The Trees of Great
Britain and Ireland” with 419 plates, by H. J. Elwes and Augustine Henry.
These volumes were the gift of Professor Sargent’s English friends and are auto-
graphed by the donors. Each volume is bound in a different wood, the binding
of volume one (beech) being taken from a portion of the foundation in Winches-
ter Cathedral in the 13th century, which was removed when repairs were made
some years ago. The 740 original drawings made by C. E. Faxon for Professor
Sargent's Silva of North America” are also replete with interest.

More than seven hundred colored plates of Chinese plants executed by native
artists more than one hundred years ago form an interesting collection of original
paintings. The colors are well preserved and the drawings have an oriental charm.
Over six hundred of these plates were the gift of one man.* Some of the plates
represent well known plants that have been introduced into this country but
many of them are very rare.

One of the most important items in the library from the point of view of the
working botanist is the tremendous collection of periodical literature from every
country of the world, containing as it does tens of thousands of original papers

*For fuller account see the Arboretum Journal , Vol. 11. pp. 131-132. 1930.

[38]

PLATE VIII

Frontispiece and first page of “Gart der Gesundheit'’ 1485.

basic to proper research. Over four hundred periodicals, transactions of societies,
etc. are currently received, with the number of publications from Russia, central
Europe and Asia constantly increasing. Nearly 200 of these are received in ex-
change for the Journal and the Bulletin of the Arboretum. There are in the library
more than 700 complete, or nearly complete, sets of periodicals; among the com-
plete sets are the Gardeners' chronicle, the Botanical magazine (the oldest serial
still in existence, having been published for 150 consecutive years), the Botanical
register , Loudon’s Gardener' s magazine, Loddiges’ Botanical cabinet and his trade
catalogues, a set of the Revue horticole, lacking three early volumes, the oldest
garden magazine still published, a set of the rare L' Horticulteur beige in five vol-
umes from 1833-1838, and a set of the Tokyo Botanical magazine complete with
the exception of a few numbers of volumes 2 and 3. There are also Dietrich’s
Oekonomisch-botanisches garten-journal in six volumes 1795-1806, almost unknown
in America, a complete set of the Verhandlungen des Vereins zur beforderung des
gartenbaues in Berlin, the Annales de Vlnstitut horticole de Fromont, 1829-34, and
Landreth’s Floral magazine and botanical repository, 1832-34, a rare American
journal.

The collection of works on forestry is unsurpassed in this country, and there
is probably not a more complete run of forestry periodicals anywhere in the wrorld,
covering as they do all the countries of Europe and Asia and ranging from Forst-
Archiv zur Erweiterung der Forst-und Jagd-Wissenschaft, 1788, to the new publica-
tions as they appear. The Arboretum periodical titles may be found in the
4 4 Union list of serials.”

Besides the works on botany, there is a large collection of books on travel,
among which perhaps the rarest is the French copy of Michaux’s Travels, a nearly
complete set of Rafinesque’s works, a large octavo edition of Audubon’s 4 4 Birds
of America” and Captain Thomas Brown’s Illustrations of the American Orni-
thology of Alexander Wilson and C. L. Bonaparte,” folio edition, published in
London, 1835. Of the latter work only thirteen copies are known to exist, eight
being in the United States.

The Arnold Arboretum library is one of few of the larger botanical libraries
in America or abroad whose treasures are made accessible to a very wide public
through the publication of its comprehensive library catalogue, in 3 volumes from
1914 to 1933, two volumes listing the works by authors and one by subjects.

To a very remarkable degree this great specialized reference library supple-
ments and completes the other special libraries in and near Boston, such as the
Gray Herbarium and the Farlowr libraries in Cambridge, and various other units
of Harvard University, the Massachusetts Horticultural Society Library and that
of the New’ England Museum of Natural History. Richest and most extensive of
all of these writhin the botanical field, it offers to the seekers of knowledge from
printed books on plants and plant science a most unique opportunity. As it stands
today it is one of the great botanical libraries of the wTorld, a monument, like the
Arboretum itself, to the ability, vision and interest of Charles Sprague Sargent,
w’ho made it possible and through whose benefactions it is constantly being in-
creased. Ethelyn M. Tucker

[40]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V JULY 28, 1937 Numbers 8-10

CLEMATIS FOR THE NORTHEASTERN STATES

CLEMATIS has long been neglected in American gardens, and
how could it be otherwise when not a single arboretum, botanic
garden, or agricultural college in the United States has a representa-
tive collection of clematis plants growing on its grounds? It is high
time that this state of affairs should be altered, and gardeners every-
where are turning with the new delight of discovery to what the late
William Robinson rightly called the most beautiful of all northern
climbing plants.

HISTORICAL NOTE

In the 1830’s and 1 840’s gardeners in Boston and Philadelphia were
importing new species and varieties of clematis from England almost
as rapidly as they were introduced from eastern Asia and elsewhere.
C. florida had been brought to Europe from Japan over sixty years
before it was exhibited at Boston in 1838; but C. SieboldiiC C. florida
bicolor ) was exhibited at Philadelphia in 1840 only three years after
the plant reached Europe; C. patens was exhibited in Boston in 1841
only five years after it reached Europe; C. lanuginosa was exhibited
in Boston in 1856, only five years behind England; and when the
first great hybrid, C.Jacfcmani, was created in England and introduced
in 1 863, it was shown in Boston by the historian Francis Parkman only
three years later. By 1890 the interest had grown to such an extent
that a Long Island nursery listed seventy-three varieties of the large-
flowered hybrids in a single catalogue.

But then fashion changed, or difficulties in growing the plants in-
tervened, or Quarantine 37 put an embargo on importations ; whatever
the reason, few clematis were seen in our gardens and few were offered
by nurserymen. Perhaps 1928 might be taken as the nadir of Ameri-
can interest in the large-flowered hybrids. In that year, although
nearly two hundred named varieties were listed in European nursery

[41]

catalogues, an authority like the late E. H. Wilson could write that
altogether there are a score or more of these named varieties, but
many are difficult to obtain in this country.” Now times have again
changed, and in answer to the new wave of enthusiasm for these
beautiful plants, new varieties are being imported and made available
to American gardeners, though most of them are really old varieties
that have been lost to us merely by our indifference.

THE GENUS CLEMATIS

The genus Clematis is a member of the buttercup family (which
includes such favorites as anemone, columbine, delphinium and peony)
and is characterized by opposite leaves, often divided into three, five,
or more leaflets, and by a complete absence of petals. The showy por-
tions of the flowers are sepals, and to call them petals is to declare
yourself a novice. In a few species, however, such as the American
C.verticillaris and the European C.alpina , the outer row of stamens has
been so modified so as to seem more or less petal-like ; and in the most
charming member of the group, the C.macropetala of China and Man-
churia, these staminodes, as they are called, would be mistaken for
petals by all but the expert. For this reason some botanists regard
this group as a separate genus, Atragene. Indeed, the species of Clem-
atis are so divergent that a few botanists split the genus into three or
even four genera, Clematis , Viorna , Atragene and Viticella ; but this is
of little concern to the gardener and is rejected by the vast majority
of botanists. I mention it merely to drive home the many-sided rich-
ness of this extraordinary genus.

For rich it is, not only in the number of species and varieties, but
in its range of size, color, and shape. It includes between two and
three hundred species, growing all over the world, on every continent
and the islands of the sea, but especially abundant in eastern Asia,
the Himalayas, and our own North America. It is found on mountains
and in marshes and deserts, and though it grows almost everywhere,
even in the Belgian Congo and the Fiji Islands, it is essentially a plant
of the temperate zone, and shows its true beauty only in such regions.
It includes climbers and non-climbers, ranging in height from twelve
inches (as in the C. Baldwinii of Florida) to thirty or forty feet (as in
the C. Vitalba of Europe). Some species are weedy things with incon-
spicuous flowers, but the vast majority are fit subjects for the garden.
In addition to these wildings, about five hundred hybrids have been
created by the genius of man, and nearly two hundred of these are
still listed by European nurserymen.

Taking the genus as a whole, including both species and hybrids,
we find flowers of almost every color, white, gray, lavender, mauve,
purple, yellow, pink, scarlet, and red (though not as yet a true red), —
of every size, small, medium, and large, with a diameter in some cases

[42]

of ten to twelve inches, — and of every shape, flat, tubular, bell-shaped,
urn-shaped, lantern-shaped, platter-shaped, single and double, flowers
like anemones or apple blossoms or semi-double roses. Nor are the
flowers the only attraction. The charm and airy grace of the foliage
make it an ornament throughout the growing season ; and a new in-
terest is added at seed-time by the fruiting-heads with their feathery
styles. In many species these fluffy masses form a display almost as
striking as when the plant is in flower.

THE SPECIES

At least forty or fifty species are hardy in New York and New Eng-
land. Of these only one is in wide use in gardens, the Japanese C.
paniculata , with its panicles of small, white, fragrant flowers in August
and September; but others of the same type, such as the Japanese
C.apiifolia and the Chinese C. brevicaudata and C. Fargesii , might be
used to produce variety. Little need be said of these except that they
lend themselves to much the same uses as screens or over fences, walls,
and tree stumps. But it may be worth noting that E. H. Wilson was
in error when he said in More Aristocrats of the Garden that C. panicu-
lata was introduced into the United States by the Arnold Arboretum,
from seeds received from Russia; and others (including myself) have
repeated the error in print. But Professor Sargent, in an article in
Garden and Forest in 1890, definitely states that this species was in-
troduced by Thomas Hogg through the Parsons Nursery, of Flushing,
Long Island, from which the Arnold Arboretum received its first plant
in 1877. The credit of making this fine plant known to American
gardens,” says Professor Sargent, 4 *is due to Mr. Edward O. Orpet,”
who is now, in hale old age, a nurseryman in California.

A selected list of species hardy in the northeastern states is ap-
pended to this Bulletin. Of these a few deserve special mention. Love-
liest of all is our own C. texensis , a native of Texas but hardy in Bar
Harbor and Ottawa. A five or six year old plant covered with thousands
of its scarlet to rose-pink urn-shaped flowers is as striking a sight as
our northern gardens can show. Unfortunately there are drab forms
of this species, and care should be taken to obtain a fine strain in which
the glowing color of the flower is preserved. Some plants are subject
to mildew, which can be controlled by a prompt dusting with Kolodust
or powdered sulphur. Other beautiful native climbers are C. crispa ,
C.troutbeckiana , C. Pitcheri , C. versicolor, all with urn-shaped flowers of
various shades, and the purple spring clematis of our eastern woods,
C.verticillaris. Of these C. crispa is second in beauty only to C. texensis,
but inferior species are often palmed off as C. crispa by nurserymen.
There is a pinkish, trumpet-shaped form which is superior to the rest
and deserves a varietal name; I venture to call it C. crispa cylindrical
and congratulate the gardener who is successful in obtaining it.

C.montana and its varieties are sure to give the New England gar-
dener heartache, for even the hardiest of them are likely to be killed
to the ground, if not entirely destroyed, in an unusually harsh winter.
The pink C.montana rubens and the white flushed pink C.montana un-
dulata are sturdier than the others, but as they flower on old wood and
will not bloom if hard hit by 4 4 Jack Frost,” we can recommend them
for this climate only with reservations despite their beauty. Of the sev-
eral yellow-flowered climbers from China and Korea, C.tangutica and
its variety obtusiuscula are the best. They are sturdy as a rock, these
slender climbers with their bright yellow, lantern-shaped flowers, and
should be in every garden. Even more beautiful are some of the
climbers of the Atragene group, the blue C. alpina of Europe, the
white C. alpina sibirica (or alba), and especially the C. macropetala of
China and Manchuria. The last has azure-blue flowers with a mass of
tongue-like staminodes that make an unforgettable sight when in full
bloom. It may seem fussy at first, but is the reverse of difficult when
once established, and it is hardy enough to thrive in Manitoba. Mr.
Ernest Markham has recently introduced a fine pink form.

Three small to medium-flowered hybrids, C.Jouiniana , C.Durandii ,
and C.aromatica , are also attractive plants. I should like to make a
special plea for the first, for C. Jouiniana (especially the form that
grows in my own garden) is a delightful plant, perhaps the easiest to
grow of the whole genus. It is a rampant climber, and in late summer
it is covered with pale lavender, tubular flowers, which resemble those
of one of its parents, C.Davidiana. A variety of C.Viticella introduced
by Lemoine of Nancy, and usually called C.kermesina, may easily vie
in popularity with C.montana rubens when it is better known. It has
bright wine-red flowers that cover the plant in great abundance.

Among the low herbaceous species for the flower border or front of
the shrubbery are C.integrifolia , C.Davidiana , and C. recta grandiflora,
the first two blue, and the last white. Some of our far western spe-
cies, such as C.eriophora, C.Scottii , C.Douglasii , and C. Fremontii , all
low plants not over two feet high, with urn-shaped or bell-shaped
flowers, are also worth a trial.

THE LARGE-FLOWERED HYBRIDS

The large-flowered hybrids are mainly derived from one European
species, C.Viticella, and three large-flowered species of Chinese ori-
gin,— C. florida, brought from Japan by Thunberg in 1776 ; C. patens,
brought from Japan by Siebold in 1836, and C./anguinosa , discovered
by Robert Fortune in Ningpo, China, and introduced in 1851. It is
by crossing these species, and some of their varieties, that the large-
flowered hybrids have been created. The first and still the most pop-
ular hybrid, C.Jackmani, was first exhibited in England in 1863, and

PLATE IX

Clematis macropetala, a charming Chinese species of the Atragene Type, in the azure-blue flowers.

Photo by Donald F. Merrett

since then several hundred have been created in Great Britain, France,
Germany, and Holland.

These hybrids are usually classified in accordance with their resem-
blance to one or other of the parent species. Five types are recog-
nized. These are: (l) Patens Type, blooming in spring on old wood;
(2) Florida Type, blooming in summer on old wood; (3) (4-) (5)
Lanuginosa Type, Viticella Type, and Jackmani Type, all blooming
in summer and autumn on new wood. It is useful for the gardener to
know to which type a given hybrid belongs, for he then knows the
characteristics of the plant and when it will bloom. But it is abso-
lutely essential that he should at least know whether it blooms on old
or on new wood, that is, on the wood of the previous year or on the
shoots of the current season. All pruning depends on this knowledge,
for a plant that blooms on old wood will not flower if it is cut back
hard either by the gardener or by 4 4 Jack Frost.” For this reason varie-
ties that bloom on new wood are in general more adapted to the
rather severe climate of the northeastern states.

It should be added that there is a sixth group, the Texensis Type,
developed during the 189CTS by crossing our native C. texensis with
various large-flowered hybrids. The Texensis Hybrids are delightful
plants, quite different from the other hybrids in shape and color. They
are all more or less trumpet-shaped, and of various shades of scarlet
and pink, with or without white markings. They are among my own
special favorites.

A list representing what in my opinion are the 4 twenty best” large-
flowered hybrids available in this country will be found at the end of
this Bulletin. All such choices are of course arbitrary, and my list con-
tains varieties that would not be included if an ampler choice were
possible. For the sake of comparison, I have added a similar list made
by an English expert of the twenty best” hybrids obtainable in Eng-
land. It will be seen that seventy percent of the English list is in-
cluded in my own, but if I were to have an unfettered choice of the
hundred or more hybrids I have myself grown, my final decision would
not exactly agree with either list.

I suggest that the novice begin with the varieties that have with-
stood the test of survival in our climate for many years, such as C.
Jackmani (purple), Madame Edouard Andre (purplish red), Madame
Baron-Veillard (lilac-rose), Gipsy Queen (dark velvety purple), C.
Henryi (enormous white), Ville de Lyon (reddish purple), and the some-
what fussier Ramona (blue). The first three are the hardiest of all ; the
color of Madame Baron-Veillard, never very distinguished, washes out
in the sun, but much can be forgiven a plant that refuses to die and that
blooms almost without interruption from midsummer to frost. After
experimenting with these, the novice, no longer a novice, can try

[46]

PLATE X

Clematis “Duchess of Albany,” one of the Texensis Hybrids.

Species

Height

Flowers

Flowering Time

Habitat

Remarks

C.aet hits {folia lutisecla

6-7 ft.

small, whitish or pale yellow

Aug. -Sept.

Manchuria

C. alpina

6-7 ft.

nodding, violet-blue

Spring

Central Europe to N.E.Asia

Charming species, which prefers a northern

C. alpina sibirica

6-9 ft.

nodding, white

Spring

Siberia

aspect. Blooms on old wood.

( C.s.alba )

C. aromatica

6 ft.

bluish violet, fragrant

Summer^ Autumn

Hybrid, CJlammula X C. integrifolia?

( C. coerulea odor ala)

C. apiifolia

10 ft.

small, dull white

Sept., Oct.

Similar to C. paniculata.

C. crispa

6-10 ft.

bluish purple, fragrant, urn-shaped

June-Se|>t.

Va. to Fla. and Tex.

Interesting climber.

C. crispa cylindrica

6-10 ft.

pinkish, trumpet-shaped

June-Sept.

A finer form.

C. Douglasii

2 ft.

tubular, purple

Spring & Summer

Colo, to Wash.

( C. hirsutissima)

C. Durandii

6-10 ft.

open urn-shaped, blue

June-Sept.

Hybrid, C.Jackmani X C. integrifolia.

C. eriophora

15 ft.

bell-shaped, purple

Spring

Wyo. to New Mex.

Leafmold and partial shade

C. Fremontii

lh ft.

bell-shaped, purple

Spring & Summer

Mo. to Nebraska

C. heracleifolia

2-3 ft.

tubular, blue

Aug. -Sept.

E. China

For the flower border or front of shrubbery.

C. heracleifolia Davidiana

2-3 ft.

tubular, blue

Aug.-Sept.

N. China

( C. Davidiana)

C. integrifolia

2-3 ft.

open urn-shaped, blue

June-Aug.

S.E. Europe to W.Asia

For the flower border or front of shrubbery.

C. Jouiniana

10-12 ft.

tubular, lavender

Aug.-Sept.

Hybrid, C. heracleifolia X C. Vitalba. Attrac-
tive and vigorous climber ; Spingarn variety
a superior form.

C. ligusticifolia

20 ft.

small, white

Sept.

Western U.S. & Can.

C. macropetala

10 ft.

nodding, azure-blue

Spring

N. China & Manchuria

A delightful climber. Pink and white forms
exist.

C. montana

25 ft.

open, white

May, June

Himalayas & China

/ C. montana and its varieties bloom on old

C. montana rubens

25 ft.

pink

June

W. China

) wood. Not dependably hardy, but rubens

C. montana undulata

25 ft.

white flushed pink

June

j and undulata are more robust than the

C. montana Wilsoni

25 ft.

white

July

China

\ others.

C. ochroleuca

2 ft.

bell-shaped, purple to creamy & yellow

May, June

N.Y. to Georgia

C. orientalis

20 ft.

yellow

Aug., Sept.

Himalayas to Persia

C. panicidata

30 ft.

small, white, fragrant

Aug., Sept.

Japan

C. Pitcheri ( C. Simsii)

20 ft.

urn-shaped, purplish

June-Sept.

Indiana to Nebr. & Texas

Somewhat “fussy.”

C. pseiuloulpina

6-8 ft.

nodding, purple to mauve

Spring

Rocky Mts.

C. recta

2-3 ft.

small, white, fragrant

June-Aug.

So. Europe

The variety grandiflora has larger flowers.

C. Scottii

1-2 ft.

urn-shaped, purplish

Spring

Rocky Mts.

Prefers well-drained soil and sunny position.

C. serratifolia

10 ft.

yellow

Aug., Sept.

Korea

Often miscalled koreana.

C. tangutica

8-10 ft.

bright yellow, lantern-shaped

June-Aug.

Mongolia to N.W. China

The best of the yellow-flowered climbers.

C. tangutica obtusiuscula

8-10 ft.

bright yellow, lantern-shaped

June-Aug.

N.W. China

“ “ “ “ “ “

C. texensis ( C. coccinea)

6-10 ft.

urn-shaped, scarlet

June to frost

Texas

A superb climber.

C. troutbeckiana

8-10 ft.

urn-shaped, lavender

Julv-Aujg.

Unknown

Floriferous.

C. versicolor

1 2 ft.

urn-shaped, purplish

July

Mo., Ark.

C. verticillaris

8-10 ft.

nodding, bluish purple

May, June

Hudson Bay to Va. & Utah

Prefers leafmold and partial shade.

C. Viorna

10 ft.

urn-shaped, reddish purple

Aug. i

Penn, to Alabama

C. virginiana

20 ft.

small, white

July to Sept.

Eastern U. S. to Kansas & Ga.

C. Vitalba

30 ft.

white, small, faintly fragrant

July-Sept.

Europe

C. Viticella

10-12 ft.

rosy purple to violet

June-Aug.

So. Europe & W. Asia

C. Viticella kermesina

8-10 ft.

bright wine-red, medium-size

Summer

Attractive climber, introduced by Lemoine.

( C. kermesina)

Nelly Moser (pale mauve with red bar), Prins Hendrik (azure blue),
William Kennett (deep lavender), Mrs. Cholmondeley (light blue),
and some of the other varieties on the appended list, especially one
of the Texensis Hybrids, such as the Duchess of Albany. The selec-
tion one makes will largely depend on one’s color preferences, for
there is not a variety on the list that could not grace the proudest
garden.

Two double-flowered varieties are now available, Belle of Woking
(pale mauve or silvery-gray) and Duchess of Edinburgh (white), both
blooming on old wood. Some single varieties, such as C. Jackmani alba
and Beauty of Worcester, may also surprise us by having an occasional
double flower. Something of the airy grace of clematis seems to me
lost in the doubles, but Belle of Woking is a superior plant.

SOIL AND SITUATION

The best time to plant clematis is in spring, but the hybrids are
usually grown in pots, and these may be set out almost any time dur-
ing the growing season. The soil should be deeply dug; the deeper
and wider the hole the better. This is not the place to discuss the
complex problem of clematis and lime, and no one is as yet in a po-
sition to say whether lime or the texture of the soil is the essential
element. It is sufficient to say that most of the wild species grow in
limestone regions. A light loam, moist and well-drained, and with
some lime added, is the ideal soil; if the soil is heavy, it may be
lightened with leafmold and a little sand ; and in the case of all hy-
brids and most species, it should be enriched with manure, — cow ma-
nure preferably on light soils and well-rotted stable manure on heavier
soils. Moisture and a cool root-run are essential to the happiness of
clematis, and in dry weather they should be given an occasional
watering.

Most clematis prefer some shade, which can be provided by plant-
ing them behind a shrub or small tree, or if this is inconvenient, they
can be given a mulch of spent hops or possibly peat moss sweetened
with lime. The ball of roots should be set two or three inches below
the surface of the soil, and the stem immediately trained to a stake
or post. I protect my own plants with a zinc collar about eight inches
high, inserted in the ground two or three inches, for any kink or break
in the stem may lead to disaster. I prefer this to the inverted bottom-
less flower-pot filled with sand that is sometimes used in Europe.

Various methods have been suggested for increasing the sturdiness
of the young plants. One method is to peg one of the lower nodes of
the stem below the surface of the soil, so that a new mass of roots may
be encouraged to grow. Another and more heroic device, in case the
plants are not thriving, is to cut the stem at the beginning of the sec-
ond year below the ground right down to the root, so as to encourage

[50]

PLATE XI

Clematis “Belle of Woking,” a double-flowered silvery-gray hybrid.

Photo by Walter Per be Wilder

the growth of new and healthier stems. But with strong plants and
the proper soil and situation, neither of these devices need be employed.

PRUNING

William Robinson, one of the greatest of all clematis enthusiasts,
once wrote in his crotchety way: By giving up all pruning trouble
is saved, and one gets a more picturesque result.” In the case of many
of the wild species this is perhaps advisable, and in the case of the
hybrids, at least in our climate, Jack Frost” often takes the matter
out of our hands. But more and larger flowers are usually the result
of judicious pruning when this is possible.

The problem depends mainly on whether a plant blooms on old or
on new wood. With Belle of Woking, Duchess of Edinburgh, Sir
Garnet Wolseley, and other hybrids of the Patens and Florida Types,
which bloom on old wood, little pruning is necessary except the cut-
ting out of dead wood, but it may sometimes be advisable to trim the
plant and cut out some of the growths for the sake of appearance even
if some bloom is thereby lost. As for the varieties that bloom on new
wood, the general rule is to cut back hybrids of the Viticella and
Jackmani Types to within two or three feet of the ground, while only
the more robust of the Lanuginosa Type should be treated in this way.
The Texensis Hybrids, like C. texensis itself, solve the problem for
themselves by dying to the ground each winter, so that one need
merely cut olf the dead canes. It should be remembered that some
of the wild species, such as C.montana rubens and C.alpina , also bloom
on old wood, and require the treatment accorded to all old wood
bloomers. But it will be found that every species and hybrid, and
even every situation, requires special treatment, and that these gen-
eral directions may need some modification in each case.

USES

Clematis fulfill the general purposes of all climbing plants, in serv-
ing as screens, draping fences, walls, trellises, and pergolas, and cov-
ering old tree stumps. Nothing makes a lovelier picture than a fine
hybrid variety in full bloom against the side of a house. Many of the
species can be used in the wild garden, and some of the lower sorts
can be used to advantage in the rock garden, as described in the Eng-
lish Gardeners Chronicle of November 9, 193.5. One of the most charm-
ing ways to grow the climbers is to plant them on the shady side of
a shrub or small tree, and let them scramble through the branches
into the sunlight. They can be used in pots and tubs for house dec-
orations or for the conservatory. They can also be used in beds, twin-
ing about branches set slantwise near the ground, with bulbous plants
set out between them to furnish bloom in spring. They make admi-
rable cut flowers, some of the varieties lasting ten days or more in

[52]

PLATE XII

Clematis “W. E. Gladstone," a fine hybrid with flowers of heavenly blue.

/ *hoto by Walter Beebe Wilder

water. It is strange that no American florists have taken advantage
of this fact, for some florists in Holland grow a hundred thousand
plants exclusively for the cut flower trade.

PROPAGATION

Most of the species can be grown easily from seed, while others,
with hard-shelled achenes, do not germinate for many months. C.tan-
gutica , for example, requires neither skill nor patience, while C.te.v-
ensis does not appear for eight or nine months, and some of the New
Zealand species require one or two years. I have found it best to sow
the seeds in the greenhouse as soon as they are ripe, but they can
also be sown in a coldframe either in autumn or in spring.

The hybrids can be propagated by layering, by grafting, or from
cuttings. Grafted plants are usually inferior to own-root plants, and
the latter should be procured whenever possible. The best way to
propagate from cuttings is to bring the plants into the greenhouse
early in January, take cuttings from the new shoots as soon as they
are ready, immerse them for about twenty-four hours in the new root-
forming substance discovered by Dr. Hitchcock and Dr. Zimmerman
of the Boyce Thompson Institute, and then insert them in sand until
they are rooted. When this method is followed, it makes little differ-
ence whether the cuttings are nodal or internodal, though by most
other methods internodal cuttings may be preferable.

BOOKS

Ernest Markham’s Clematis, The Large and Small Flowered (London
and New York, 193o) is a useful and practical little book, with a
special chapter on “Clematis in America.” Moore and Jackman’s
The Clematis as a Garden Flower (London, 1872; revised edition,
1877), though out of date, is still indispensable. Those interested in
the species should consult Rehder’s Manual of Cultivated Trees and
Shrubs, Bean’s Trees and Shrubs Hardy in the British Isles, and Bailey’s
Standard Cyclopedia of Horticulture. The last deals with the large-
flowered hybrids also. A complete check-list of the hybrids will be
found in the National Horticultural Magazine , January, 1935. A list
of nurseries offering interesting species and hybrids was published in
the Bulletin of the Horticultural Society of New York, January, 1936.

J. E. Spingarn

[54]

PLATE XIII

Clematis lanuginosa, a Chinese large-flowered species from which many
of the hybrids have been derived.

Photo hy Walter Beebe Wilder

APPENDIX

TWENTY BEST LARGE-FLOWERED HYBRIDS
OBTAINABLE IN THIS COUNTRY

Variety

Color

Type

Ascotiensis

azure-blue

Viticella Type

Belle of Woking

double, silvery-gray

Florida Type

Comtesse de Bouchaud

satiny rose

Jackmani Type

Crimson King

bright red

Lanuginosa Type

Duchess of Albany*

[see footnote]

Texensis Type

Elsa Spath

bright blue

Lanuginosa Type

Gipsy Queen

dark velvety purple

Jackmani Type

Henryi

white

Lanuginosa Type

Jackmani superba

dark violet-purple

Jackmani Type

Lanuginosa Candida

grayish white

Lanuginosa Type

Lady Caroline Neville

delicate mauve with darker bars

4 4 *4 4

Lord Neville

dark plum

4 4 4 4

Madame Edouard Andre

velvety purplish red

Jackmani Type

Mrs. Cholmondeley

light blue

4 4 4 4

Nelly Moser

pale mauve with red bar

Lanuginosa Type

Prins Hendrik

azure-blue

4 4 4 4

Ramona

blue

4 4 4 4

Sir Garnet Wolseley

bronzy blue with plum-red bar

Patens T.vpe

Ville de Lyon

reddish purple

Viticella Type

William Kennett

deep lavender

Lanuginosa Type

All bloom on new wood except Belle of Woking and Sir Garnet Wolseley.

It might be of interest to compare with this list a similar one prepared for me
a few years ago by a well-known firm of clematis specialists in England, since
many of the varieties are the same, and the others will soon be available in this
country. This list of the “twenty best large-flowered hybrids obtainable in Eng-
land* ’ includes : Ascotiensis, Belle Nantaise (delicate lavender). Belle of Woking,
Comtesse de Bouchaud, Crimson King, Elsa Spath, Fairy Queen (pale flesh with
pink bar), Gipsy Queen, Henryi, Jackmani superba, Lady Northcliffe (deep
lavender), Lady Betty Balfour, (deep velvety purple), Lasurstern (deep purplish
blue), Lord Neville, Madame Edouard Andre, Mrs. Cholmondeley, Mrs. Hope
(satiny mauve with darker bar), Nelly Moser, Ville de Lyon, and William Ken-
nett. All these bloom on new wood except Belle of Woking and Lasurstern.

There is only one pure white variety on either list, and other whites worthy
of mention are Miss Bateman and The Bride, blooming on old wood, and Madame
van Houtte and Marie Boisselot, blooming on new wood. Other beautiful va-
rieties not yet available here are W. E. Gladstone (lilac), Otto Froebel (gray
with a lovely flush), Perle d’Azur (light blue), blooming on new wood, and La
Lorraine (pink suffused with lavender) and Edouard Desfosse (violet with deeper
bars), blooming on old wood.

*Or any other Texensis Hybrid, Duchess of York, Countess of Onslow, Grace Darling,
Admiration, all with trumpet-shaped flowers in shades of pink or scarlet.

[ 50 ]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V SEPTEMBER 10, 1937 Numbers 11-13

BARBERRIES IMMUNE OR HIGHLY RESISTANT
TO BLACK STEM RUST OF CEREALS

THE family Berberidaceae contains a great number of ornamental
flowering shrubs which are at once pleasing and useful. Bright
red persistent berries enrich the beauty of many of the species; and
the foliage, which colors brilliantly in the fall, aids considerably in
causing the plants to merit the praise of exacting gardeners. Various
immune species of Berberis and Mahonia are worthy of wider use than
they now enjoy and should be better known to the general public.

Approximately 140 different species, forms, and hybrids of Berberis
(including our two native species) have been found to be susceptible
to Puccinia graminis , a parasitic fungus which in the spring and sum-
mer causes the devastating stem rust of cereals.

LIFE HISTORY OF THE STEM RUST FUNGUS
In the fall this fungus forms its thick-walled overwintering spores
on the grain stems and stubble, and is often called <<lolack rust” be-
cause of the spore color. In spring, the comparatively large and heavy
black rust spores germinate and produce much smaller ones, known
as sporidia, which are easily carried by air currents. Of the countless
numbers of sporidia produced only a comparatively few are by mere
chance transported to susceptible hosts. If these tiny sporidia fail to
fall on susceptible species of Berberis or Mahonia , they die and the life
cycle of the rust is terminated ; but if they fall on susceptible host
species, only favorable weather is necessary to produce infection. Fol-
lowing infection small flask-shaped bodies, containing minute spores,
first make their appearance just beneath the surface of the upper epi-
dermis of the leaves. Soon after their formation orange cluster cups
are formed on the under surfaces of the leaves, within which are pro-

[37]

duced chains of large aeciospores ; an average-sized barberry bush can
produce more than 64,000,000,000 of these spores at one time. Only
these aeciospores can effect initial spring infection on the cereals in
the northern States. We have here a fungus that has five distinct
spore forms during a complete life cycle. In addition, it has an in-
teresting requirement involving alternate hosts ; the barberry is neces-
sary for one stage, while the important cereals, such as wheat, oats,
barley, and rye, must be present for another stage.

HISTORY OF BARBERRY ERADICATION

The barberry-cereal relationship of the fungus that causes stem rust
was first demonstrated on a scientific basis in 1865 by the celebrated

German scientist Anton de Bary. More than a hundred years earlier

New England farmers observed that rust was more severe on grains
growing near barberry bushes, and they voluntarily eradicated their
barberries for the specific purpose of protecting grains from the dam-
aging effects of the disease. About this time many laws were passed,
both in this country and in Europe, condemning barberry bushes be-
cause they caused 4 ‘blasting” of the grains. The earliest recorded
legislation of this kind was enacted in Rouen, France in 1660. In
1726 Connecticut passed a law requiring that all barberry bushes grow-
ing in the vicinity of grain fields be destroyed, and similar action
was taken by the Massachusetts legislature in 1754. Unquestionably
the empirical knowledge of the barberry-rust relationship expressed
both by New England farmers and by husbandmen on the Continent
led de Bary to make his study. It is this destructive disease of wheat
and other cereals that makes current knowledge of the rust-immune
species of the Berberidaceae so important from a horticultural stand-
point.

In 1918, when nearly 200 years had elapsed after the first laws
were passed condemning barberries in the United States, the first
organized eradication program was undertaken. During this period
certain species of barberry, particularly Berberis vulgaris L. , became
firmly established throughout the northern part of the United States.
As the number of these bushes increased in the important grain grow-
ing areas there was a corresponding increase in the number and se-
verity of stem rust epidemics.

With the beginningof the cooperative barberry eradication program
nearly 20 years ago, thirteen of the north central States, namely,
Colorado, Illinois, Indiana, Iowa, Michigan, Minnesota, Montana,
Nebraska, North Dakota, Ohio, South Dakota, Wisconsin, and Wy-

oining, passed laws restricting the propagation and distribution of
rust-susceptible species. These States were further protected by a
Federal quarantine (No. 38 revised) which provides that no plants,
cuttings, stocks, scions, buds, fruits, seeds, or other plant parts cap-
able of propagation, of the genera Berberis , Mahonia , or Mahoberberis
shall be moved or allowed to be moved interstate from any State of
the continental United States or from the District of Columbia into
any of the protected states, “unless a permit shall have been issued
therefor by the United States Department of Agriculture, except that
no restrictions are placed by these regulations on the interstate move-
ment either of Japanese barberry ( Berberis Thunbergii ) or any of its
horticultural varieties, or of cuttings (without roots) of Mahonia
shipped for decorative purposes and not for propagation.” In addi-
tion to the above named states, Missouri, Pennsylvania, Virginia, and
West Virginia are now actively engaged in an eradication program.

IMMUNE TYPES

Fortunately, there are twenty-seven species of Berberis and three
species of Mahonia which have been found to be either immune or of
such a high degree of resistance to rust that they can be grown any-
where without endangering our cereal crops. Indeed, the choice of
species is so ample and of such quality that the immune species will
fulfill most of the purposes for which barberries are used in ornamental
plantings.

The following barberries can be grown anywhere in the United
States without restriction.1

B. Thunbergii

B. Thunbergii var. purpurea
B. Thunbergii var. Maximowiczii
B. Thunbergii f. minor
B. Thunbergii var. plurijiora
B. Thunbergii f. erecta

Permits are required under the regulations of the black stem rust
quarantine (No. 38 revised) for interstate movement of the following
immune or highly resistant species or varieties into any protected
State, and for such movement from any protected State into any pro-
tected State. Application for such permits should be addressed to the
Division of Domestic Plant Quarantines, Bureau of Entomology and
Plant Quarantine, U.S. Department of Agriculture, Washington, D.C.

1 The six forms listed here all have conspicuous fruit, and are winter
hardy in the Arnold Arboretum.

Evergreen

Deciduous

B. buxifolid 1

B.aemulans 2

B.candidula 3

B. Beaniana 1,2

B. Chenaultit3

B. circumserrata 1,2

B. Darwin ii 1,3

B.concinna 1,2

B. Gagnepainii 3

B. dictyophylla f. albicau/i.

B. Juliana e3

B. Ed geworthiana2

B. sail guinea0

B. Gilgiana 1,2

B. Sargentiana 3

B.loreana 1,2

B .stenophylla

B. mentorensis

B. triacanthophora 3

B. Potanini 1,3

B. verruculosa 3

M. Aquifolium 1,2

M. nervosa 1,3

M. repens1’2

1 Bearing conspicuous fruit.

2 Winter hardy in the Arnold Arboretum.

3 Require winter protection at the Arboretum and in northern States.

All species, varieties, and hybrids of Berberis or Mahonia not listed
in the foregoing groups are prohibited shipment into the protected
States or from any protected State into any protected State, and per-
mits will not be issued for such shipment.

DECIDUOUS SPECIES

Berberis Thunbergii and varieties. This species has long been a
favorite and is found in nearly every lawn and garden. It is also ex-
tensively used for hedge plantings. Thunberg, sometime previous to
1784, was the first European to notice this barberry in Japan, erro-
neously referring to it as B.cretica L. In 1821 A. P. DeCandolle assigned
the currently used binomial B. Thunbergii to it. It was introduced to
Russia sometime before 1874 by E. von Regel, who received seeds
from Japan at the Imperial Garden at St. Petersburg. These plants
grown in Russia by E. von Regel eventually produced seed and from
this source seeds were received at the Arboretum on January 14, 1875.

A compact form of the species originated at the Arnold Arboretum
as a chance seedling sometime before 1900. It has smaller leaves,
shorter internodes, more slender and delicate branches, a better
rounded growth habit, and more dwarfed stature. This form is now
known as Berberis Thunbergii f. minor. Although not cultivated exten-
sively as yet, it does, however, hold a well-deserved position in many
shrub plantings; its leaves color well in the fall and the red berries
remain attached during the winter.

[60]

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Berberis koreana a hardy barberry already available from some nurseries
and a worthy successor to the old-fashioned B. vulgaris.

The form B. Thunbergii var. purpurea , very widely known, differs
from the type principally in the purplish to reddish color of the leaves ;
the fullest and most brilliant color develops on plants grown in full
exposure to the sun.

Berberis Thunbergii var. Ma.vimozciczii is characterized chiefly by more
twiggy branches, purple bark, and acute leaves which are green be-
neath. Seed of this variety was sent by the Imperial Botanic Garden,
Tokyo, Japan, to the Arboretum in March 1901.

The name of the form called B. Thunbergii var. pluriflora is some-
what confused. The varietal name pluriflora should be applied to B.
Thunbergii plants which bear three or four flowers and fruits at the
end of a short peduncle. Unfortunately, this name has often been
applied to the hybrid B.ottawensis ( B. Thunbergii > B. vulgaris), hav-
ing B. Thunbergii-Wke leaves and bearing flowers and fruits in racemes
and umbels. This hybrid is equally as undesirable as B. vulgaris.

A new and superior selection of B. Thunbergii has recently made its
appearance. Mr. M. Horvath of Mentor, Ohio, during his work on
one of the large estates in the city of Cleveland, discovered a plant
of B. Thunbergii with a strong tendency toward erect growth. He gath-
ered the seeds from this plant and from their progeny selected seed
from the most upright type. This process was repeated until the fifth
generation, wherein Mr. Horvath found what he considered the per-
fect spire-like plant that he was seeking, properly called Berberis
Thunbergii f. erecta. Unfortunately, this plant has had the erroneous
polynomial B. Thunbergii var. pluriflora erecta applied to it. It is not
a selection from a pluriflora type, but is a derivative of the typical
form of B. Thunbergii. This selection is upright in growth and is ad-
mirably adapted for formal hedge plantings. It is propagated vegeta-
tively and produces abundant red berries; the foliage changes to a
brilliant red in the fall.

B. mentorensis. Through the hybridizing efforts of Mr. Horvath
another barberry was introduced to the trade in 1934. Berberis men-
torensis is the result of crossing B. Thunbergii with B.Julianae. The
cross was made in 1924, and the hybrid which appeared in 1925 is
propagated vegetatively. This hardy, three-fourths evergreen plant
shows strong resemblance to both parents. The young branches are
at first purplish to light brown, angled and strongly grooved ; the
elliptic-ovate leaves which cover the bush to the ground are coriaceous
in texture, dark green above and pale beneath ; the margins are
sparsely spinulose-dentate, and the apex of the leaf is tipped with a
little spine. The plants in the Arboretum are apparently becoming

[62]

well established, and this year for the first time are covered with flow-
ers ; one fascicle examined contained over forty blossoms. In size and
color the flowers closely resemble those of B.Thunbergii. When es-
tablished, the strong growth of this distinctive shrub, armed with
stiff spines, is very suitable for protective and ornamental hedges,
while it may also be used as a specimen or in natural growing group
plantings. In the autumn many leaves assume a pinkish to reddish
tinge, later becoming somewhat bronzed. A few leaves remained at-
tached and green during the entire past winter in the Arboretum.
Where evergreen barberries fail to withstand rigorous winters, this
plant will usually survive, for during the unusually cold winter of
1933-34 it withstood temperatures greater than -20° F. in Ohio with-
out any apparent injury.

B. Gilgiana. Several outstanding barberries which have been grow-
ing for many years in the Arboretum will very probably become
well known within the next few years. The silky-leaved Berberis Gil-
giana is one of these. It is a tall hardy plant with spreading branches
and pleasing proportions. The young branchlets are grooved, slightly
pubescent, and yellow or purplish brown. The elliptic-obovate or
mostly oblong leaves are finely pubescent above and more conspicu-
ously so beneath. Abundant yellow flowers are borne in dense racemes
on slender puberulous peduncles. In the fall the oblong-ovoid fruits
are at first somewhat greenish in color, but change first on the sun-
exposed side to pinkish hues and finally to a lovely deep blood red.
The foliage also colors handsomely in the fall. The fine specimen on
the Overlook in the Arboretum is from seed collected by Furdom
(No. 589) and received from China in February 1911.

B. circumserrata. Another Chinese barberry which has much merit
but is little known, is Berberis circumserrata. It develops into a rounded
bush up to 6 feet high and has a stiff twiggy habit of growth. The
leaves are somewhat papery in texture, and color brilliantly in the
autumn. The large ellipsoid-oblong fruits which taper to a distinct
style are yellowish-red in color and are borne singly or in groups of
three to five, prominently supported by rigid peduncles and strong
pedicels. The fruit persists well through the winter. This is a hardy,
handsome shrub of a distinctive type.

B. koreana. From Korea comes a hardy barberry of outstanding
character. Seeds of B. koreana were first sent to the Arboretum by T.
Uziyama in 1904. Our plant is upright in growth habit and has now
attained a height of 6 feet. The clusters of large globose-ovoid red
fruit persist over the winter. They combine with the reddish to dark

brown branches and the many leaf-like spines of the same color to
produce an interesting plant during the dreary winter months. In the
spring and summer new interest comes with the yellow flower clusters
and the development of the large, rounded, thick paper-like leaves
which take on a deep red color, and other hues, in the autumn. In
recent years a number of nurseries have propagated this plant, and
although a considerable proportion of the seedlings produce plants of
upright growth there will be an appreciable number of less desirable
growth forms. This hardy barberry is a fit type to replace B. vulgaris
wherever hedges or individuals of that habit are desired.

B. concinna. Our Berberis concinna , which was received from the
Royal Botanic Gardens, Kew, in March, 1885, failed to withstand the
New England climate. It is reported, however, that at Kew, B. con-
cinna forms a low bush of 3 feet in height, of close compact habit. Its
leaves are lustrous green above, white beneath, obovate in shape, an
inch or less in length, and petiolate, with the midrib ending in a sharp
spiny tooth. The solitary, pendant flowers are deep yellow and a half-
inch in diameter. The fleshy berries are red. This plant was intro-
duced to Kew by Sir Joseph Hooker from Sikkim about 1850. Under
suitable climatic and soil conditions it is a very lovely barberry, dis-
tinct because of the vivid whiteness of the under surface of the leaves.

B. aemulans. The hardy, but quite uninteresting Berberis aemulans
was introduced to the Arboretum in 1908, from seed collected by
Wilson in western China.

B. Edgeworthiana reached England about 1845; but the earliest
plants at the Arboretum came from seed sent by Mr. R. M. Parker in
1920 from India, where it is native. The species, like B. aemulans ,
apparently has little to recommend it from a horticultural standpoint.

B. dictyophylla f. albicaulis. Graceful and of slender habit, Ber-
beris dictyophylla f. albicaulis is unusual and charming because of the
dense snow-white bloom covering the new shoots and the under sur-
face of the leaves. This form apparently turned up by chance as a
minor segregate of B. dictyophylla, grown at Hesse’s nursery at Weener,
Germany, shortly before 1916. The species is native to southwestern
China. Most of the flowers are solitary and rather inconspicuous. The
fruit is not abundant enough for ornamental value, but this is unim-
portant in view of the graceful sprays of lovely white stems and the
chalky under-surfaces of the leaves, which make a splendid display
in both summer and winter. The plant is not hardy at the Arboretum,
but it can be grown south of Washington, D.C., or somewhat farther
north if given sufficient winter protection.

[64]

Berberis circumserrata, another handsome shrub of distinctive habit.

B. Beaniana. Trim, slow-growing Berberis Beaniana has withstood
the New England climate since 1923. This species was introduced to
England in 1904, seeds being collected from western Szechuan, China,
by a Veitch expedition. The plants at Kew were first reported to have
flowered and fruited in 1914. It is not surprising then that the plant
at the Arboretum, received from Kew Gardens, England, in April,
1923, has failed to blossom until this year when a few flower clusters
appeared. Judging from flowering and fruiting herbarium specimens,
this will be a very attractive species from a horticultural standpoint.
It has reddish, angled branches, small elliptic-lanceolate leaves which
are whitish beneath, and it bears panicles of yellow flowers which are
followed by long, purple fruits covered with bloom.

B. Potanini is closely related to B. Beaniana, but it is less hardy.
This species, like the above, is native to China. Our plants which
fail to survive the local climate were grown from seed received from
Kew Gardens in February, 1927. B. Potanini is remarkable for its
numerous long spines. The somewhat leathery or rigid, lanceolate
to ovate leaves are armed with from 1 to 4 spiny teeth on each side
and are whitish beneath. The flowers are produced in racemes, and
the fruits are subglobose, red, and tipped with a short style. It should
be of distinct value farther south.

EVERGREEN SPECIES

B. Darwinii, a native of Chile, it is not hardy at the Arboretum;
it is root hardy but not top hardy at Washington, D. C. In milder
climates, as along the Pacific Coast, B. Darwinii thrives. This beauti-
ful evergreen was discovered by Charles Darwin in 1835 while on his
famous voyage on the Beagle. In 1894 it was introduced to cultivation
by William Lobb for the Messrs. Veitch, Chelsea, England, from the
Island of Chiloe. When grown under suitable conditions. B. Darwinii
is a plant of great beauty, especially when laden with a profusion of
deep orange blossoms early in the spring. In the autumn when it
is burdened with a large crop of bluish berries it is also very attrac-
tive, and at all seasons the small holly-like leaves produce a pleas-
ing effect.

B. stenophylla. The beautiful, graceful hybrid Berberis stenophylla
( B. Darwinii X B.empetrifolia) first appeared in the nursery of Fisher
& Holmes of Hansworth, near Sheffield, England, about 1880. Under
conditions such as obtain in the milder parts of England it grows to
a height of 8 to 10 feet, is evergreen, and has a graceful habit which
neither parent possesses. In addition it has the floral beauty of B.

[66]

Darwinii and the added hardiness of B.empetrifolia, for in April and
May it is blanketed with rich golden blossoms. In Newr England, the
plant loses most of its leaves in winter and does little more than cling
to life. The Arboretum specimen, which dates from 1884, is scarcely
more than 2 feet in height. Even the milder weather of Washington,
D. C., is not sufficient to bring out its potential beauty. Probably,
then, only in the regions where B. Darwinii thrives will this gorgeous
plant come into its own.

B. buxifolia. Another evergreen species from South America, this
plant is approximately as hardy as B. stenophylla and like it has just
managed to survive at the Arboretum where it has been growing since
1884. This species was introduced to England about 1826 by Ander-
son, the botanical collector wTho went with Captain King’s expedition
to survey the Magellan Straits. It will forma tall bush (up to 10 feet)
of erect stiff habit. The leaves are leathery or hard in texture, the
flowers are borne one or two in a fascicle, and the globose fruits are
dark purple.

B. triacanthophora. China has produced several of our hardiest,
most useful evergreen barberries. The most attractive, Berberis tria-
canthophora, is one of our hardiest evergreens and is a graceful shrub
with spreading branches which are well armed with strong slender
spines. The narrow leaves are of a clear bright green color above and
somewhat whitish beneath. They are borne in almost flattened whorls
which aid in giving the shrub a distinctive airy lightness that is very
pleasing. This plant was collected by Wilson and sent to the Arbo-
retum in 1907.

B. Julianae. One of our hardiest and strongest growing evergreen
barberries is B. Julianae. This species was sent to the Arboretum by
Wilson in 1908. It is the tallest and most vigorous of the Chinese
group, remarkable for its dense, glossy, dark green, luxuriant leaves.
The stiff, yellowish gray, somewhat angled stems, armed with vicious
spines, make it particularly valuable for protective hedges. The fas-
cicles of yellow flowers are followed by ovoid fruits which are bluish-
black, covered with bloom, and have a short but distinct style.

B. Sargentiana. The much less hardy B. Sargentiana has rounded
slender branches which are graceful in comparison with those of B.
Julianae. The young branches are reddish in color, and the leaves,
which are much longer and wider than those of the foregoing species,
are closely spiny-serrate and firmly coriaceous in texture. The yellow
flowers are borne in fascicles. The ovoid fruits are bluish black with
a slight bloom and with a sessile stigma Wilson sent this species to

[«7]

the Arboretum in 1908, but it had been introduced to England by
Veitch in 1907.

B. Gagnepainii. The undulating margins of the firm, dark green,
narrow leaves of Berberis Gagnepainii give this species a distinctive ap-
pearance. The spreading branches are well armed with three-parted
spines one-half to three-quarters of an inch long which, together with
the sharp forward-pointing teeth set in the margins of the linear-
lanceolate leaves, provide it with unusually effective weapons of self-
defense. It is a native of Szechuan, China, and was introduced for
the Messrs. Veitch, Chelsea, England, by Wilson about 1904. Our
first plant came from Chelsea in 1908. This species bears large yellow
flowers in clusters of about six or sometimes more in the axis of each
whorl of leaves. The fruits are long, oval, black berries covered with
a bluish bloom.

B. verruculosa. The warty branches of Berberis verruculosa account
for the specific name of this species, which is a sturdy, dwarf, ever-
green shrub. The leaves are leathery in texture, lustrous green above
and white beneath, and the recurved margins are armed with a few
spiny teeth. The plant is suitable for rock gardens, edges of shrub
border, and fronting foundation planting. Carefully pruned it will
form spiny green domes which are very attractive. This fine evergreen
surely is worth the trouble of winter protection and the necessary
pruning because of its lovely form and color. The large golden flowers
are solitary or in few-flowered fascicles. The berries are black and cov-
ered with bloom. The species was introduced into England by Wilson
in 1904 from western China; five years later Wilson sent seeds direct-
ly from China to the Arnold Arboretum.

B. candidula. The less hardy B. candidula was first collected by
Farges in 1894, and in 1895 was raised from seed by M. Maurice de
Vilmorin in France. Although it has been growing at the Arboretum
since 1929, it scarcely more than remains alive even with considerable
winter protection. It is a dwarf evergreen shrub with smooth arching
branches. The tufts of small leaves, borne in the axils of the stiff
three-parted spines, are dark shining green above and show a vivid
blue-white color beneath. It produces large, yellow, solitary flowers.
The species is suitable for rock gardens, but will thrive only under
mild climatic conditions.

B. sanguinea. From the mountains of Szechuan, China, Berberis
sanguinea,\va.s introduced to France by M. Maurice de Vilmorin in
1898. The specific name refers to the color of the flower stalks and
sepals. It is an evergreen shrub that will attain a height of 6 to 9

[68]

PLATE XVI

Berberis Gilgiana, hardy in Boston and valued for its fruit and autumn color.

feet. The pale grayish, smooth branches are armed with long slender
spines and bear tufts of leaf clusters. The leaves are deep green in
color, linear-lanceolate in shape, tapering to a fine point, and the
margins are armed with sharp, forward-pointing teeth. The fascicles
of golden yellow flowers, with the sepals reddish on the outside, are
borne on reddish stalks of unequal length. The berries are small and
blue-black in color.

B. Chenaultii is a hybrid concerning the origin of which no definite
information is available. The name suggests, however, that it may
have originated in the nursery of Leon Chenault et Fils, Orleans,
France. The plant appears to be a hybrid of B. Gagnepainii and B.
verruculosa. The branches are verruculose, which is characteristic of
the latter species, and the medium long, somewhat undulating leaves
suggest the former. In stature it is intermediate between the two,
and although sightly is scarcely an improvement on either species.

All of the evergreen barberries need more or less winter protection
in New England either to survive our worst winters or to insure against
possible injury during milder ones. It is necessary to cover the ground
sufficiently to prevent freezing of the roots, thus permitting the re-
placement of water lost by the plants through transpiration.

It may be timely to suggest the futility of trying to obtain immune
species from seed obtained from an arboretum, or any other place
where the different species grow in close proximity. Hybridization,
which takes place very readily, will be responsible for many disap-
pointments. Seeds gathered from immune species in such a place will
probably give rise to hybrids susceptible to attack by the rust fungus,
so one should obtain species of known and dependable purity for real
satisfaction. Barberry plants of dependable ancestry can usually be
obtained from nurserymen who hold Federal permits to ship immune
barberries into protected States, since such permits are not issued
until their nurseries have been freed of all susceptible bushes.

Our other native immune members of the Berberidaceae are thus
far restricted to three species of the genus Mahonia. The members of
this genus have unarmed stems, pinnate evergreen leaves, and gen-
erally form handsome undershrubs or, rarely, small trees. The dwarf,
creeping Mahonia repens is native to the Rocky Mountain region, while
the low-growing M. nervosa and the taller upright M. Aquifolium are
native to the Pacific Northwest.

Mahonia repens is very useful as a ground cover, especially under
trees and shrubs or in locations not subjected to the full rays of the
sun. It thrives without an abundance of moisture and requires very

[70]

little attention after it is once well established. Its shapely foliage,
its abundance of yellow flowers early in the spring, and the bluish
fruit in the fall make the plant an ideal cover for areas that might
otherwise be bare and unsightly.

M. Aquifolium. The taller Mahonia Aquifolium , Oregon-grape as
it is known in its native habitat, is a beautiful plant which likewise
enjoys considerable shade ; in fact, it grows better under such con-
ditions than in the open. These two species are not only of much
ornamental value to the home surroundings but for soil erosion and
wild-life conservation they will surely serve a valuable purpose. The
sheltering leaves and branches aid in the protection of wild life and
the edible fruits contribute to the subsistence of birds and other ani-
mals.

M. nervosa is a handsome, low-growing plant with lustrous, rigidly
coriaceous leaflets armed with spiny teeth. The stem bears conspicu-
ous, persistent lanceolate bud scales which are 2 to 3 cm. long. The
bright yellow flowers are borne on erect racemes 8 inches or more in
length. The fruits are rounded oblong, small, and of purplish blue
color.

Mahoberberis Neuberti, a cross between Mahonia Aquifolium and
Berberis vulgaris , is very susceptible to black stem rust. This hybrid
has often been erroneously called B. ilicifolia.

In view of the increasing number of States excluding susceptible
species of Berberis and Mahonia , it becomes more and more desirable
for all nurserymen interested in barberries to rid their nurseries of
rust-susceptible plants and to establish a stock of the immune species
sufficient for normal horticultural requirements.

Only recently four additional States (Missouri, Pennsylvania, Vir-
ginia, and West Virginia) have asked to be included in the area pro-
tected by Quarantine No. 38 (revised). If this expansion in the pro-
tected area is made there will be 17 states in which the interstate
shipment (into or between) of susceptible species of barberry is pro-
hibited by Federal quarantine. All these States are now cooperating
with the United States Department of Agriculture in the barberry-
eradication program.

Owing to the steadily diminishing market for barberries that are
susceptible to attack by the stem rust fungus, many nurserymen are
now restricting their stock to immune species, thus becoming eligible
to apply for a Federal permit to ship approved species to any point
from which orders are received. Customers will automatically assist
in the stem rust control program if, when making purchases, they

will restrict their barberry selections to one or more of the rust-immune
species described in this bulletin.

L. M. Ames, Associate Pathologist ,
Bureau of Entomology and Plant Quarantine,
U. S. Department of Agriculture.

NOTES

Fascicle five of the important “leones Plantarum Sinicarum” by
Doctor Hsen-Hsu Hu and Professor Woon-Young Chun, issued by
the Fan Memorial Institute of Biology, Peiping, China, is dedicated
to “Alfred Rehder, Associate Professor of Botany and Curator of the
Herbarium of the Arnold Arboretum of Harvard University, mentor
of our student days.” Both authors received a part of their training
at the Arboretum.

The present contribution consists of folio plates 201 to 250 with
explanatory text in English and in Chinese, and includes illustrations of
six species of Rehderodendron, a genus dedicated to Professor Rehder.

Fascicle one was dedicated to Charles Sprague Sargent, first Direc-
tor of the Arboretum; fascicle two to Augustine Henry, famous bo-
tanical collector in China; fascicle three to Ludwig Diels, Director
of the Botanical Garden, Berlin, Germany ; and fascicle four to E.

D. Merrill, present Director of the Arnold Arboretum.

The comprehensive “Bibliography of Eastern Asiatic Botany” by

E. D. Merrill of the Arnold Arboretum, and E.H. Walker of the
Smithsonian Institution, is being published by the Arnold Arboretum,
and should be off the press late this fall or early in 1938. This will
be a quarto volume of approximately 650 pages. It contains 23,000
author entries appertaining to the area from Tibet to Kamchatka,
south to Formosa and Hainan. Practically every language of western
Europe is represented, with many thousand entries in Russian, Chi-
nese and Japanese. Each entry is provided with a brief abstract.
Publication was rendered possible by three special gifts to the Arbo-
retum. The preparation of the manuscript covered a period of ten years.

[72]

ARNOLD ARBORETUM

HARVARD UNIVERSITY

BULLETIN

OF POPULAR INFORMATION

Series 4. Vol. V DECEMBER 10, 1937 Numbers 14-15

VIBURNUMS

HE beauty and interest of many a shrub border is greatly en-

A haneed by viburnums. These plants are most serviceable, and
every outstanding shrub garden should include at least a few in one
place or another. A good selection of viburnums will provide interest
in the garden during the whole year, since several are valued for their
flowers in the spring, others are valued for their good foliage, and
some for their summer fruits. In autumn many are outstanding when
covered with bright colored berries, while most of the Viburnum spe-
cies have good autumn coloration. In some species the fruit remains
attached throughout the winter.

Thus the viburnums are a group of plants that add interest to the
garden throughout the year. Some are common in cultivation while
others are still rare. The Arboretum collection contains about seventy
species and varieties. These include most of the hardy species and
varieties available in nurseries in this country, together with some
rare types that are not generally available; some of these are of
botanical interest but have little ornamental value. Supplementing
those species hardy in New England are a considerable number of
species that will thrive only under more favorable climatic conditions
farther south.

Sometimes, in considering a large group of plants such as the vibur-
nums, the gardener is apt to lose sight of the wide ornamental possi-
bilities available by a careful selection of species within a single genus.
This Bulletin is devoted entirely to a consideration of the viburnums
that are hardy in the north. It is hoped that the following data may
increase interest in this group of plants and lead to a fuller apprecia-
tion of the horticultural possibilities of certain species.

Viburnums for Flower

The first viburnum to bloom in the Arnold Arboretum is Viburnum
fragrans. Ordinarily, one or two flowers in a cluster start to open early
in March, the remaining flowers finally opening in April. Since this
species blooms so early in the season, the flowers are often killed by
late frosts. Sometimes the flower buds themselves are partly frozen,
so that the inflorescences have a blasted appearance when open. Con-
sequently, Viburnum fragrans is not of great value in New England
although the flowers are very fragrant and certain of the plants have
a picturesque upright habit of growth. Farther south, where the pos-
sibility of winter injury is less, it is more valuable from a landscape
point of view.

The second viburnum to bloom is V. Carlesii. It forms a round,
broad bush and usually starts to bloom about the last week in April.
By the early part of May it is in full bloom. Because of its time of
flowering, it is not often injured, and is therefore considerably better
for garden use than is V . fragrans. It, too, is very fragrant, and its
small white flowers (pink in bud) are very similar in size and shape
to those of our native mayflower or trailing arbutus. Viburnum bitch-
iuense is a third representative of this group with fragrant flowers. The
young plants are very difficult to distinguish from V. Carlesii , but as
the plant grows older it becomes considerably more loose and open
in growth habit, and consequently is not as valuable for landscape
planting as is V .Carlesii. Unfortunately various American nurserymen
ordering seed of V. Carlesii from Japan have received seed of V.bitch-
iuense. Because of the similarity of the young plants, it is often very
difficult to correct the error.

Two other viburnums are valued for their large, sterile flower clus-
ters and are commonly called the snowballs. The first, V. Opulus roseum
(V .Opul us sterile in the trade) is too common in our gardens. It is the
taller growing of the two and the large sterile flowers are borne in
round masses of about the same size as those of the ordinary snowball.
Unfortunately the leaves, young shoots, and flower clusters are sub-
ject to severe infestations of plant lice which materially disfigure all
parts of the plant. For this reason, it should not be planted. By far
the better of the two, and a form which is not susceptible to infesta-
tion by plant lice, is the Japanese snowball, V.tomentosum sterile ( V.
tomentosum plicatum). It is not quite as hardy as the common snowball,
being killed to the ground as far south as Philadelphia during the se-
vere winter of 1 933-34-, (though certain individual plants survived
without injury) but in normal winters it is perfectly hardy in New

PLATE XVII

\ iburnum prunifolium. This plant usually grows with a single leader
although it can be treated as a shrub.

England. Besides having large flower clusters, its branches are hori-
zontal, like those of V .tomentosum, giving the plant a unique layered
appearance, particularly in the winter when the branches are bare.
A third snowball, F .macrocephalum sterile or the Chinese snowball, is
not hardy in the north, but in the south it is very popular for its large
round clusters of flowers.

The rest of the viburnums have large flat clusters of flowers, the
flowers themselves being very small and creamy white in appearance,
very similar to those of Queen Anne’s lace or wild carrot. There are
a few species, like V. Sargenti , which have a few conspicuous sterile
flowers on the outside of the cluster, making them slightly more con-
spicuous than the others. These viburnums are valued for their small
flowers. It is true that F.dentatum, V.dilatatum and F .pubescens Canbyi
are outstanding when in full bloom because there is always a wealth
of flower clusters almost covering the plant, but other than the few
species mentioned above most of the viburnums cannot be considered
as having conspicuously beautiful flowers. Most of them bloom during
May and June.

Viburnums for Fruit

The majority of the viburnums, with the exception of the double-
flowered varieties and a few others, have bright colored fruits. They
range in color from yellow to red to blue and black with varying in-
termediate shades. As a group, the viburnums are valued for their
fruits more than for any other reason, and a careful selection of them
should insure very colorful spots in the garden from late summer until
far into the winter. Some of the fruits are simply black like those of
F . acerifoliiim . These are not particularly conspicuous, but nevertheless
are very attractive to the birds. The fruits of some others, like those
of F. Sieboldii , are eventually black, but before maturity they are a
brilliant red. Since they remain on the shrub for some time while
they are so colored, they lend much interest to the plant in the late
summer and fall. Enough cannot be said about the good landscape
possibilities of F .Sieboldii, since it is not only excellent from the stand-
point of bright colored fruits and tall often tree-like habit, but it is
also a splendid foliage plant. Even after the fruits have fallen, the
bright red-colored fruit stalks remain on the plant a long time, lend-
ing considerable color to the plant until late in the fall.

Other viburnums, like F.cassinoides and V. Lentago , have most in-
teresting fruits, since they change in color from green to pink and red
to dark blue. Often several of these colors are evident on the same

PLATE XVIII

Viburnum dilatatum xanthocarpum, one of the rare yellow-fruited viburnums.

cluster or even on the same berry. Such a characteristic gives the
plant great interest in the fall.

Certain viburnums like V. Opulus and V . trilobum ( V . americantim )
keep their fruits a greater part of the winter, providing there are not
too many birds in the vicinity. Others, like V. Jragrans, ripen early
in the summer, but as these are soon eaten by the birds the color
characters of the fruit cannot be counted upon to be of any landscape
importance.

Yellow-fruited Varieties

Although most of the viburnums have red or blue fruits, some are
yellow at maturity, and it is these that are worthy of more general
cultivation. They should not be used in place of the red-fruited forms,
but in conjunction with them. There are at least three, all of which
are growing in the Arnold Arboretum but none of which are listed by
American nurserymen, namely : V . dilatatum . vanthocarpum , V. Opulus
xanthocarpum , and V. Sargenti Jlavum. One other, V. setigerum auran-
tiacum , has good orange-red fruits rather than yellow ones. This plant
should also be grown. Since the autumn color of the foliage of each
species is dark red, the yellow fruits show off to excellent advantage
after the foliage has turned color in the fall. A planting of consider-
able autumn interest might be made by using two plants of the red-
fruited V .dilatatum back of a single yellow-fruited variety. The growing
of these yellow-fruited forms cannot be recommended too highly, both
for nurserymen and gardeners themselves. Some growers take the
misguided view that since there is no demand for certain rare plants,
such plants have no sales value. This certainly should not be true of
the yellow-fruited viburnums, for once they have become known to
the public, there is no reason why they will not be even more popular
than are the red-fruiting forms.

Landscape Uses

As a group, the viburnums are vigorous growing shrubs which enjoy
a good sunny location and can be used either in mass plantings or as
specimens. As a specimen foliage plant, there is probably nothing
nicer than V. Sieboldii with its dark green leaves and its masses of
billowy foliage. The exotic viburnums, particularly, are used as speci-
mens, while the native ones are used considerably in naturalistic plant-
ings. Viburnum acerifolium and V. alnifolium are two plants which grow
better in the cool shade of the woods than they do in the open sun.
Viburnum pubescens Canbi/i also is excellent for naturalistic planting.
As a general rule the other species like sunny locations, and when so

[78]

situated they will flower and fruit much better than if grown in contin-
ual shade.

In the fall, the predominating autumn color of the entire group is red.
Some, like V. prunifolium , are a brilliant red, while others like V . dil-
atatum are a dull red. Viburnum acerifolium has almost a purple autumn
color and is probably one of the few members of the group showing
no shade of red in the fall. In order to get the best color effects from
the foliage in the fall, most of the viburnums should be grown in the
full sun, particularly in situations where they are exposed to the warm
sun in the late afternoons of September and October.

The species differ considerably in the mature height to which they
grow. Viburnum prunifolium has a single trunk and is considered a small
tree; V. Lentago sometimes grows into a small tree. The dwarf variety
of the cranberrybush, V. Opulus nanum, never gets over 18 inches tall,
and is splendid for low rock plantings or for formal edging material
around small low gardens. Other species range in height between
these two extremes. The chart gives the approximate height of the
various species, as they are used in landscape plantings.

Tender Viburnums

In the south there are several outstanding viburnums that are high-
ly valued for garden use. These would include the evergreen V. ja-
ponicum , V. odoratissimum , V. tinus , and several of its varieties, V .
rhytidophyllum , V. suspensum , V . macrocephalum , and V. Burkiooodii .
Viburnum Burkwoodii has only recently been introduced into the coun-
try, but midwestern nurserymen are now growing it in quantity. It is
a cross between V . utile and V. Carlesii. In a protected place in the
Arboretum it withstood the severe winter of 1933-34 in splendid con-
dition, but it cannot be grown in the open in New England. South of
Philadelphia it is reliably hardy and is fast becoming a favorite for its
lustrous green foliage and pretty flowers. It is not as dense and com-
pact in its growth habit as grafted plants of V .Carlesii.

Donald Wyman

[79]

SOME

GOOD ORNAMENTAL VIBURNUMS,

HARDY IN THE NORTH

Date of

Native of

Time of

Color of fruit

Value

Value

Approx-

For

V.aeerifolium

introduction
into U. S.

U.S.

effective

fruit

F

black

of

fruit

of

flower

imate

height

naturalistic

planting

*

V. affine hypomalacum

u.s.

F

black

-

-

6'

*

V.alnifolium

U.S.

S

changing red to black

*

-

9'

*

V.bitchiuense

1911 ?

Japan

1 s

black

-

*

10'

V.Burkwoodii

1924

V. utile V.Carlesii in England

-

black

-

**

10' ?

V.Carlesii

1902

Korea

-

black

-

**

M

V.cassinoides

U.S.

1 F

changing red to black

**

-

8'

*

V.dentatum

U.S.

SF

blue

**

15'

*

V.dilatatum

about 1865

Japan & China

FW

red

**

*

9'

V.dilatatum xanthocarpum

1919

Orig. U.S.

FW

yellow

**

*

9'

V. fra grans

1915

China

■ S

changing red to black

*

9'

V. La n tana

prior to 1828

Europe & W. Asia

F

changing red to black

*

-

1 5'

*

V. Lentago

U.S.

FW

black

**

*

30'

+

V.Opulus

prior to 1790

Europe and N. Africa

FW

red

**

*

12'

V.Opulus nanum

prior to 1880

Orig. in Europe before 1 845

-

E

-

||

V.Opulus roseum

prior to 1771

Cult, in Europe

-

-

-

**

12'

(V.Opulus sterile)

V.Opulus xanthocarpum

about 1898

Orig. in Europe prior to 1 840

FW

yellow

**

*

12'

V. prunifolium

U.S.

FW

black

**

**

15'

*

V.pubescens Canbyi

U.S.

FW

black

*

9'

*

V.rhytidophyllum

1908

China

F

changing red to black

-

-

9'

V. Sargenti

1892

N . VV. Asia

s

scarlet

**

*

9'

V. Sargent i flavum

1904

Orig. in U.S.

s

yellow

**

*

9'

V.setigerum (V.theiferum)

1901

China

F

red

*

-

12'

V.setigerum aurantiacum

1908

Orig. in U.S.

F

orange-red

*

-

12'

V. Sieboldii

about 1880

Japan

s

changing red to black

**

*

so'

V.tomentosum

about 1865

Japan & China

s

changing red to black

**

*

9'

V.tomentosum sterile

about 1844

Japan & China

-

-

-

**

9'

(V.tomentosum plicatum)

V.trilobum (V.americanum)

U.S.

FW

red

*

*

20'

*

V. Wrightii

1892

Japan

S

red

**

*

9'

* fair (

** very good
S summer
F fall
W winter
no value

Sources for rare woody plants. In connection with some other
work, the Arboretum has just completed checking some 1200 nursery
catalogues for rare woody plants. If you have difficulty in locating
sources for such rare woody plants, write to the Arboretum, and it
may be that a source can be located for you.

• Note. Arrangements have been made with Mr. Richard Archbold,
leader of the Archbold Expeditions to New Guinea, whereby the
specimens collected by Mr. L. J. Brass, the Expedition Botanist, will
be identified under the auspices of the Arnold Arboretum. Mr. Arch-
bold is about to leave this country on his third trip to New Guinea
under the auspices of the American Museum of Natural History and
expects to be in the field for about one year.

These Bulletins will now be discontinued until the spring of next
year.

Subscription renewals for 1938 are now due. Send the subscrip-
tion price of $1.00 to the Bulletin of Popular Information, Arnold
Arboretum, Jamaica Plain, Mass., at your early convenience.

INDEX TO SERIES 4

VOLUME V

Synonyms are in italic; illustrations in bold face type.

Acer griseum, 25

- Tschonoskii, 25
Alyssum gemonense, 30
Ames, L.M., 57-72

Arnold Arboretum, Identifica-
tion of plant material, 13-16
— , Trip through during lilac
time, 29-32
Azalea, Amoena, 18
-, Arnold, 32
, Coast, 18
, Flame, 18, 23
, Hinodegiri, 18
, Japanese, 18, 23
, Korean, 18, 25
, Pinkshell, 18
, Poukhan, 31
, Royal, 18, 31
, Snow, 18
, Swamp, 18
, Sweet, 18

, Torch, 18, 20, 22, 30-32
amoena , 20
arbor escens, 24
all antic a , 23
ca.lendulacea , 23
Hinodegiri, 20
indica alba, 20
japonic a, 23
ledifolia alba, 20

- mucronata, 20
mucronulata , 1 8

nudijlora, 23
rosea, 23
pontica, 23
poukhanense, 22
rosea, 23

Sch/ippenbachii, 22
Vaseyi, 22
— viscosa, 24
Azaleas, 17-24, 28
, Ghent, 23, 32
• — , ^Mollis” hybrids, 23, 32
, Order of bloom, 18
Barberries, 25, 26
, Hybridization, 70
immune or highly resistant
to black stem rust of cereals,
57-72

Barberry eradication, History
of, 58, 59

, Cooperative program, 58-60
Barberry-cereal relationship, 58
Beech, 32
Berberis, 5 7-72

, Deciduous species, 60-66
, Evergreen species, 66-72
, Immune types, 59, 60
aemulans, 60, 64
Beaniana, 60, 66
buxifolia, 60, 67
candidula, 60, 68
Chenaultii, 60, 70
circumserrata, 60, 63

Plate XV, 65

— concinna, 60, 64

— cretica, 60

— Darwinii, 60, 66, 67

— dietyophylla, 64

— albicaulis, 60, 64

— Edgeworth iana, 60, 64

— empetrifolia, 66, 67
Gagnepainii, 60, 68
Gilgiana, 60, 6,8

Plate XVI, 69

— ilicifolia, 71
Julianae, 60, 67
koreana, 60, 68, 64

Plate XIV, 6 1

— inentorensis, 60, 6*2, 68

— ottawensis, 62

— Potanini, 60, 66

— sanguinea, 60, 68

— Sargentiana, 60, 67

- stenophylla, 60, 66, 67
Thunbergii, 59-62

— ereeta, 59, 62
Maximowiczii, 59, 62

— minor, 59, 60
pluriflora, 59, 62

— ereeta , 6*2

— purpurea, 59, 6*2

- triacanthophora, 60, 67

- verruculosa, 60, 68

— vulgaris, 58, 62, 71
Bibliography of Eastern Asiatic

Botany, 72
Bussey Hill, 25-28
Plate VI, 27
Callicarpas, 25
Cherries, Flowering, 26
, Japanese, 9-12
— ’ Propagation, 10
Cherry, Higan, 12
— , Sargent, 9, 10, 12

— , Yoshino, 12
Chinese collection, 25-28, 81
Plate VI, 27
Clematis, 41-56
— , Books, [recommended], 54
— , [Chart listing important
landscape characteristics
of species and varieties],

48, 49

, Florida type, 46, 52
, Historical note, 41, 42
, Jackmani type, 46, 52
, Lanuginosa type, 46, 52
, Large-6o\vered hybrids,

44, 46, 50

, Patens type, 46, 52
, Propagation, 54
, Pruning, 52
, Soil and situation, 50, 52

— , Texensis hybrids, 46, 52
, Texensis type, 46, 52
, Twenty best large-flowered

hybrids obtainable in this
country, 56
— , Uses, 52, 54

, Viticella type, 46, 52
for the northeastern states,

41

— alba, 44
— alpina, 42, 44, 52

sibirica, 44

apiifolia, 48

— aromatica, 44
- Baldwinii, 42

— “Belle of Woking”,

Plate XI, 51

brevicaudata, 48

— crispa, 48
cylindrical, 48

Davidiana, 44
Douglasii, 44

[ 84]

A

Durandii, 44
“Duchess of Albany”,

Plate X, 47
eriophora, 44
Fargesii, 43
tforida, 41, 44
florid a bicolor , 41
Fremontii, 44
Henryi, 46

Ramona* ", 4(5
“Ville de Lyon”, 46
integrifolia, 44-
Jackmani, 41, 44, 46
alba, .50

“Gipsy Queen”, 46
Madame Baron- Vil lard
46

Madame Edouard
Andre**, 46
Jouiniana, 44
kermesina, 44
lanuginosa, 41, 44
Plate XIII, .5.5
macropetala, 42, 44
Plate IX, 4.5
montana, 44

rubens, 44, .5 2
undulata, 44
paniculata, 43
patens, 41, 44
Pitcheri, 43
recta grand iflora, 44
Scottii, 44
Sieboldii, 41
tangutica, 44, 54
— obtusiuscula, 44
troutbeckiana, 43
versicolor, 43
verticillaris, 42, 43
vitalba, 42
Viticella, 44

[85]

“W.E. Gladstone”,

Plate XII, 53

Collection, The Chinese, 25-28
Crabapple, Bechtel, 30
Cytisus praecox, 31
Davidia involucrata, 25
Dogwood, Flowering, 29, 32
Dove-tree, 25, 28, 31
Forsvthia, Korean, 2, 4, 6
europaea, 2, 4, 5
Plate I, 5
intermedia, 4, 6
Plate I, 5
primulina, 4
spectabilis, 4
Plate II, 7
vitellina, 4
ovata, 2, 4, 6
Plate I, .5
Plate II, 7
suspensa, 2, 4
Plate I, 5
atrocaulis, 3
Fortune i, 2
pallida, 3
pubescens, 3
Sieboldii, 2, 3
variegata, 3
viridissima, 1, 3, 4
Plate I, .5
koreana, 3
Forsythias, 1-6
, Hardiness, 2
, Key to (After Rehder’s
Manual), 4
, Pruning, 2
Fothergilla, 25
Honeysuckles, 25, 26
Hydrangeas, 25
Iberis sempervirens, 30
Tenoreana, 30

Identification of plant material
at the Arnold Arboretum,

13-16

— , Suggestions for shipping,

14, 15

Kolodust, 43

Library of the Arnold Arbore-
tum, 33-40

Fifteenth century books, 36
-, Folios of Dioscorides, 37
, Illustrated folios, 38

-, Illustration of title-page of
Jacquin’s “Selectarum stir-
pium americanarum histo-
toria” (cir. 1 780) ,

Plate VII, 35

, Illustration: Frontispiece
and first page of “Gart der
Gesundheit” 1485,

Plate VIII, 39
— , Incunabula, 36

, Periodical literature, 40
-, Photographs, 34
-, Pre-Linnean books, 36
Lilac, Japanese tree, 30
— , Persian, 30
- hedge in Arnold Arboretum,

31

— time in the Arnold Arbore-
tum, 29-32

Mahonia, 57-60, 70-72

— Aquifolium, 60, 70, 71

— nervosa, 60, 70, 71
— , repens, 60, 70, 71
Magnolia acuminata, 29
Mahoberberis, 59, 60, 7 1

— Neuberti, 71
Malus spectabilis, 30
Merrill, E.D., 72
Pinxterbloom, 18

— , Downy, 18

Plant material, Identification of,

13-16

Plant quarantines, Division of,

59

Prunus avium, 10
— incisa, 10
~ nipponica, 10
Sargenti, 9, 10, 12
Plate III, 11
serrulata sachalinensis,

9, 10, 12

- subhirtella, 1, 10, 12

autumnalis, 12
pend u la, 12

- yedoensis, 1 0, 1 2
Puccinia graminis, 57
Quarantine, 37, 41
Quince, Japanese, 30
Rehderodendron, 72
Rhododendron, 17

— , Korean, 17, 18
— arborescens, 18, 24

- atlanticum, 18, 23

- calendulaceum, 18, 23

— canadense, 18, 20

— dauricum, 17

— gandavense, 23

— japonicum, 18, 23
Kosterianum, 23

- luteum, 23

— “Miss Louisa HunnewelP’ 23

— molle, 23

— mucronatum, 18, 20

— mucronulatum, 17, 18, 25

— nudifiorum, 18, 23, 31

— obtusum, 20, 22

- amoenum, 18, 20, 32
- X R. obtusum Kaempferi ,
20

~~ arnoldianum, 18, 20
“ Hinodegiri”, 18, 20

- Kaempferi,

18, 22, 23, 25, 29

- roseum, 18, 23, 29, 81
Schlippenbachii, 18, 22, 25

Plate IV, 19
Vaseyi, 18, 22, 29, SO

— viscosum, 18, 24
yedoense poukhanense,

18, 22, 25

Plate V, 21

Yodogawa”, 22

Rhododendrons, Differences be-
tween Rhododendrons and
Azaleas, 1?

Rhodora, 18, 20
canadensis, 20
Sargent, Professor Charles
Sprague, 12, 28, SI, 72
Spingarn, J.E., 41-56
Spray Program at Arnold Arbo-
retum, 8

Sulphur, Powdered, 4S
Syringa amurensis, SO

- ehinensis, SO

Saugeana, SO
persica, SO
pubescens, SO

— villosa, SO
vulgaris, SO

“Clara Cochet”, SI
Congo”, SO
“Edith Cavell”, SI
“Lucie Baltet”, SI
“Ludwig Spaeth”, 30
“Macrostachva”, SI
“Mrs. W.E. Marshall” SI
Negro”, SO

“President Lincoln”, SI
“Vestale”, SI

Viburnum acerifolium, 76-79
alnifolium, 78
americanum , 78
bitehiuense, 74
Burkwoodii, 79
Carlesii, 74, 79

— cassinoides, 76
dentatum, 78

— dilatatum, 76-79

xanthocarpum, 78
Plate XVIII, 77

— fragrans, 74, 78

- japonicum, 79
Lentago, 76, 79
mac roceph alum, 79

— sterile, 75
odoratissimum, 79
Opulus, 76
nanum, 79
roseum, 74
sterile, 74
xanthocarpum, 78
prunifolium, 79
Plate XVII, 75

~ pubescens Canbyi, 76, 78
rhytidophyllum, 79
Sargenti, 75
flavum, 78

■ setigerum aurantiacum, 78
Sieboldii, 76, 78
s us pen sum, 79
tinus, 79
tomentosum, 76
~ plica turn, 74
sterile, 74
trilobum, 78
utile, 79
Viburnums

- , Chart of best for ornamental
use, 80, 81

. Landscape uses, 78, 79
. Tender species & varieties, 79
. Yellow-fruited varieties, 78

- for flower, 74, 75
for fruit, 75, 78

Viorna, 42
Viticella, 42, 46, 52
Wilson, E.H.,

28, 42, 43, 64, 67, 68
Wisteria, Chinese, 32
, .Japanese, 32

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