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EDWARD S. AYENSU
and

ALBERT BENTUM

SMITHSONIAN CONTRIBUTIONS TO BOTANY • NUMBER 14

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SMITHSONIAN CONTRIBUTIONS TO BOTANY • NUMBER 14

Commercial Timbers
of West Africa

Edward S. Ayensu
and Albert Bentum

ISSOEDt

AUG 819T4

SMITHSONIAN INSTITUTION PRESS

City of Washington
1974

ABSTRACT

Ayensii, Edward S., and Albert Bentum. Commercial Timbers of West Africa.
Smithsonian Contributions to Botany, number 14, 69 pages, 28 plates, 1974. —
The xylem anatomy of 28 species of commercially and potentially commercial
timbers of West Africa is described together with information pertaining to
seasoning qualities, durability and working properties, as well as the uses of
wood. A comprehensive discussion on the mechanical properties, establishing the
methodologies for evaluating the potential utilization of these woods, has been
included. Shrinkage and swelling in wood have always presented problems in
the utilization of woods. A discussion relating to the differences among (a)
moisture content change and shrinkage, (b) the effect of drying conditions on
shrinkage and (c) the variation in shrinkage in different species is presented.
I’o aid both beginning students and to refresh the minds of practicing wood
technologists, a glossary of the principal terms used in describing the minute
features of timbers has also been added.

Official pubiication da if is handstaniped in a limited number of initial copies and is recorded
in the Instittition’s annual report, Smithsonian Year. ,SI Prkss number 4924. Series cover design:
Leaf clearing from the katsiira tree Cercidiphyltuni japonicum Siebold and /uccarini.

Library of Congress Cataloging in Publication Data
-Ayensu, Edward S.

Commercial timbers of West Africa.

(Smithsonian contributions to botany, no. 14)

Includes bibliographical references.

I. l imber — Africa, West. 2. Trees — Africa, West. 3. Wood. I. lientum, Albert, joint author.

II. J itle. 111. Scries: Smithsonian Institution. Smithsonian contributions to botany, no. 14.
QK1.S2747 no. 14 [SD528J 58L.U8s [674'.!4'0967J 73-12959

For sale by liic Siipcrinlcndcnt of i)o(umcnis. U.S. Government 1‘rinting Oflicc, Washington. D.C. 20402

Pnee $1.65 (paper cover)

Contents

Page

Introduction 1

Mechanical Properties of Wood 1

Shrinkage and Swelling in Wood 3

Descriptions of Species Arranged by Families 7

Anacardiaceae

Antrocaryon micraster A. Chevalier 8c A. Guillaumin 8

Burseraceae

Canarium sclnoeinfurtliii Engler 10

Combretaceae

Terrninalia ivorensis A. Chevalier 12

Tenninalia siiperba Engler &; Diels 14

Lecythidaceae

Combretodendron macrocarpum (Palisot de Beauvois) Keay 16

Leguminosae

Copaifera salikounda Heckel 18

Cylicodiscus gabunensis (Taub) Harms 20

Distemonanthus benthamianus Baillon 22

Meliaceae

EntandropJtragma angolense (Welwitsch) A. C. DeCandolle 24

Entandrophragrna candoUei Harms 26

Entan d roph ragma cylindricurn Sprague . , 28

Entandrophragrna utile (Dawe 8c Sprague) Sprague 30

Giiarea cedreta (A. Chevalier) Pellegrini 32

KIwya grandifolia A. C. DeCandolle 34

Khaya ivorensis A. Chevalier 36

Eovoa trichilioides Harms 38

T u rraeanthus africanus Hutchinson 8c Dalziel 40

Moraceae

Antiaris africana Engler 42

Chlorophora excelsa (Welwitsch) Bentham 8c J. D. Hooker 44

Musanga cecropioides R. Brown 46

Ochnaceae

Lophira alata Banks ex C. E. Gaertner 48

Rubiaceae (Naucleaceae)

Mitragyna stipulosa (DeGandolle) O. Kuntze 50

Nauclea diderichii (DeWildeman Sc Durand) Merrill 52

Sapotaceae

Tieghemella heckelii Pierre ex A. Ghevalier 54

Sterculiaceae

Nesogordonia papaverifera (A. Chevalier) R. Capuron 56

Tarrietia utilis Sprague 58

Tripiochiton scleroxylon K. M. Schumann 60

iii

Lllmaceae

Celtis mildbraedii Engler 62

References 64

Glossary 65

Commercial Timbers
of West Africa

Edward S. Ajensu
and Albert Bentum

Introduction

In several developing countries the tendency to
concentrate on using a few well-known woods for
internal consumption and for export has virtually
killed every initiative by students of wood tech-
nology to explore the numerous potentially com-
mercial woods available in the forests. In West
Africa, for example, the mere mention of “com-
mercial timbers” focuses attention on the African
mahogany and the African white wood. In recent
years, however, attempts have been made by the
forest products institutes and wood technologists
to explore the utility of every available timber in
developing countries.

This work includes the anatomical descriptions
of both the known commercial timbers and many
potentially commercial woods of West Africa.
Other information, such as the habitat of the trees,
the general distributional range, durability, working
qualities, and the effects of seasoning, as w'ell as
the known uses of each species, is included. Apart
from xylem anatomy, two major areas that concern
wood technologists are the mechanical properties
and the shrinkage and swelling of woods. In order
to aid students we have included general accounts
on these topics.

The accompanying photomicrographs are in-
tended to help in the microscopic identification of

Edward S. Ayensu, Department of Botany, Smithsonian Insti-
tution, Washington, D.C. 20560. Albert Bentum, Forest Prod-
ucts Research Institute, Kumasi, Ghana.

the secondary xylem in laboratory work.

We are most grateful to Dr. David B. Lellinger
and Ms. Cynthia Ostroff for reading the manuscript
and for their most useful suggestions.

Mechanical Properties of Wood

In West Africa there are large areas of unex-
ploited tropical forests with substantial volumes
of lesser known timber species. In order to evaluate
the potential utilization of those species, a knowl-
edge of their properties is an absolute necessity for
feasibility studies on the establishment of wood
industries.

Tests are performed in accordance with inter-
national standards recommended by the Third
Conference on Wood Technology under fao
auspices. The standard tests, usually conducted on
clear specimens that are 2X2 cm (2X2 in) in
section, are the static bending, compression parallel
to grain, compression perpendicular to grain, im-
pact bending, hardness (or Janka indentation),
shear parallel to grain, cleavage, and tensile tests.

All these tests must record the direction in which
the sample is tested, for, owing to the anisotropic
nature of wood, any figure denoting the strength
of a piece of timber is valueless unless the direction
relative to the grain in which the tests were made
is definitely stated (Henderson, 1939:77).

Data from these tests afford comparisons among
various species and allow the establishment of cor-
rect strength functions, which are used in conjunc-

SMITHSONIAN CONTRIBUTIONS TO BOTANY

tion with test results of structural size timbers to
furnish the basis for fixing allowable stresses.

Generally, three important properties are com-
puted under each test; they are the modulus of
rupture, the load to the elastic limit, and the mod-
ulus of elasticity. Other special values demanded
by special use may also be computed.

The modulus of rupture is the maximum load
(weight) the test specimen will bear in the center
when the two ends are supported. For any timber,
a characteristic figure is obtained from the test
results, which enables comparison to be made witlu
any other kind of timber, and from which the size
of beams for different structural purposes can be
computed. The modulus of rupture is considered
to be, in some respects, the average measure of the
stress to which the wood fibers are subjected at the
moment of their failure.

The elastic limit shows what load a beam can
safely carry without any permanent deformation.
When a beam carries a load below this limit, it
will regain its previous position undeformed when
the load is removed; should the load be in excess
of the limiting value, the fibers will be distorted
and the wood will not regain its original shape.

The modulus of elasticity gives an indication of
the stiffness of the timber and is a theoretical figure
expressing the load required to stretch a section
1 cm- (1 in-) to double its length (Henderson,
1939:83). The speed with which the load is applied
in the following tests is very important. As long as
the limit of elasticity is not reached, the speed is
not too important. However, above the limit of
elasticity the rate of loading affects the strength,
so that in all tests the loading must be continuous
and at a standard rate.

Properties of the wood such as strength, hard-
ness, tension, and compression are significantly
affected by moisture content. As moisture content
increases these values decrease, although not to the
same extent. For example, compression values
decrease to a lesser extent with increase in moisture
content than do tension values. Average moisture
content while testing must, therefore, be stated so
that, where necessary, corrections may be made in
the calculations if they differ appreciably from
standard test-pieces.

The static bending test, by international require-
ments, must be conducted on specimens having a

span-depth ratio of 1:14. Center loading must be
used for this test. This means that the two supports
must be 28 cm (28 in) apart, and the cross-section
of the small, clear specimens must be 2 cm- (2 in-).
During the test the load is applied at one point in
the center and gradually increased until the speci-
men fails. For actual test procedure the reader is
referred to standard test procedures described in
the British Standard 373, Methods of Testing Small
Clear Specimens of Timber (published by the
British Standards Institution, 1957), and Wood,
Wood Preservatives and Related Materials (pub-
lished by the American Society for Testing
Materials).

The laboratory tests are carried out on small
straight-grained specimens chosen for their freedom
from defects. It is practically impossible to come
across pieces of wood more than 20 or 30 cm long
without variations in grain, texture, and other
properties, all of which may greatly affect the
strength of wood. Figures obtained from these
laboratory tests must, therefore, be applied with
care to actual structural timbers.

Compressioji tests are carried out both parallel
and perpendicular to the grain. Compression paral-
lel to the grain specimens is required to be 2 X 2
X 6 cm (2 X 2 X 6 in). The load is gradually
applied on the end until the specimen fails by buck-
ling or cracking. The values from these tests are
required for pit-props, columns in buildings and
bridges, wagon spokes, etc.

Compression perpendicular to the grain speci-
mens has the same dimensions, and the test is
carried out in a somewhat similar manner. A rec-
tangular plate is gradually pressed to the side of
the block until the cells are crushed beyond recov-
ery. Values from these tests are required for railway
cross-ties and similar uses in which pressure is
placed on the side face of the timber.

Impact lest pieces are usually 2 X 2 X 30 cm (2
X 2 X 30 in). The specimen is supported on both
ends, with the distance between the centers of the
two supports being 24 cm (24 in) apart. The load
is applied at the center of the test piece. A 3.3-lb
weight is allowed to fall freely from successive
heights which increase by regular intervals until
either complete failure or deflection of 6 cm (6 in)
has been reached. The data obtained from this test
are used to compute the toughness value (the abil-

NUMBER 14

ity to withstand shocks) of timber used for sporting
goods and other purposes for which toughness is
needed.

The hardness test determines the load needed to
press into the block a small steel ball 1.13 cm (0.444
in) in diameter to a depth one half its diameter.
The load is applied continuously during the test
at a speed of 0.25 in per minute. The figure ob-
tained in this way indicates the resistance of the
wood to penetration of foreign bodies and serves
as a basis for comparison with other timbers.

Shear tests utilize a block of wood, usually 2 cm"^
(2 in-'^), which is subjected to pressure in such a way
that one-half of the block is slid over the other half.
The maximum load is recorded and the apparent
shearing stress is computed in kg/cm^ (Ib/in-).

In compression and also in tension (tensile)
tests, wood shows its maximum strength along the
grain, but under shearing tests greater strength is
shown across the grain. This may be explained by
the fact that it is easier to slide wood fibers along
one another than to shear them crosswise.

Cleavage tests indicate the strength per cm of
width (or per inch of width) to resist splitting. The
load is applied gradually but continuously until
fracture occurs. The maximum load only is
recorded.

Tensile tests of two types are usually conducted:
tension parallel to the grain and tension perpen-
dicular to the grain. The maximum loads recorded
enable the resistance to tension or tensile strength
in each case to be computed.

Shrinkage and Swelling in Wood

What is Shrinkage? — When we talk about
shrinkage and swelling in wood we refer to the
behavior of wood in relation to the changes in
moisture content. For example, if a piece of wet
wood is kept in the air it will lose moisture; on the
other hand, if dry wood is kept in a moist, humid
atmosphere, the wood will absorb moisture. Thus
the moisture content of the wood will change with
changes in the atmospheric conditions until the
wood reaches a moisture content which is in equi-
librium with the amount of moisture content in
the surrounding atmosphere. The moisture content
of the wood at this stage is known as the equilib-
rium moisture content (emc).

The most important elements of the wood that
play significant roles in these phenomena are the
fillers (the structural elements in hardwoods) and
the tracheids (the structural and conducting tissue
in softwoods).

Most of the degrade (cracking and distortion),
which often takes place during drying of timber,
would not occur if shrinkage and the accompanying
stresses could be eliminated. Although elimination
of shrinkage is not possible, drying conditions can
be controlled to keep degrade to a minimum.
Changes of shape such as bowing, cupping, and
twisting are sometimes aggravated by grain direc-
tion or method of sawing, i.e., whether flatsawn or
quartersawn. Opening of glued joints and the stick-
ing of drawers, windows, and doors may be caused
by distortion or swelling as a result of changes in
the moisture content of the wood.

Moisture Content and Shrinkage. — In freshly
felled timber the moisture can be conveniently
divided into two parts: the free water, which is held
in the cell cavities, and the bound water, w'hich is
absorbed into the cell walls. During drying all the
free water in the cell cavities is gradually removed
and the wood is said to have reached the fiber satu-
ration point. The remaining moisture is contained
in the cell wall in the form of bound water. Based
on the w’eight of dry wood the equilibrium moisture
content at this point usually varies between 25 and
30 percent of the original free and bound water
content. In most cases, the loss of free water in
the cell cavities does not affect the structure of the
wood. When, however, drying progresses below the
fiber saturation point and bound water is removed
from the cell walls, appreciable shrinkage of the
wood occurs, and changes in other physical char-
acteristics, such as strength and electrical resistance,
take place (Johnston, 1970). To better understand
this, it is necessary to consider the structure of the
cell wall. It is made up of small particles of cellu-
lose strands called microfibrils, which are separated
by a film of water. As the water is removed, the
microfibrils move closer together and the sum total
of these small contractions is the shrinkage observed.
Generally speaking, then, normal shrinkage does
not take place during drying until the fiber satura-
tion point is passed.

Drying Conditions and Shrinkage. — When mois-
ture evaporates from the surface of a piece of wet

SMITHSONIAN CONTRIBUTIONS TO BOTANY

wood, there is a lowering of moisture concentration
in the outer layers. This causes moisture to move
from the wetter interior (a region of high concen-
tration ) towards the drier surfaces. The structure
of wood, however, is such that it oEers some resist-
ance to the passage of moisture; in some species this
resistance is considerable. If evaporation from the
stirfaces occurs at a faster rate than the flow of
moisture from the interior zones to these surfaces,
the moisture gradient within the wood wall increase.
If the outer layers are dried below the fiber satura-
tion point, they will have a marked tendency to
shrink. This shrinkage is resisted by the wetter
interior, so that a state of stress develops with the
outer layers in tension and the inner core in com-
pression. If the stresses become stifliciently severe,
the outer layers may break (surface checking) or
they may become stretched without breaking. In
this latter case the wood is said to be case-hardened
( Johnston, 1970).

The rate at which moisture moves in the wood
depends on (1) the relative humidity of the sur-
rounding air, (2) the steepness of the moisture
gradient, and (3) the temperature of the wood.
The difference betw’een the relative humidity of
the air and the moisture content in the wood is of
utmost importance. Low relative humidity increases
the capillary flow of moisture from the wood and
stinudates diffusion of water by lowering the mois-
ture content at the surface (Panshin and De Zeeuw,
1964:171 ).

Air has a definite maximum capacity for holding
water vapor at a given temperature. The partial
pressure that may be exerted by the vapor at the
given temperature is referred to as the saturation
vapor pressure. The total pressure of a mixture of
air and water vapor is the sum total of the partial
pressures exerted separately by the air and vapor.
If the water vapor pressure in a quantity of air is
less than saturation vapor pressure, then that air
is capable of taking up more moisture and the
difference between the actual vapor pressure and
the saturation pressure can be regarded as the “dry-
ing potential” of the air. (The relation of the actual
vapor pressure to the saturation pressure, expressed
as a percentage, is known as the relative humidity
of the air; Johnston, 1970). Therefore, for wood to
dry to the point where shrinkage takes place, i.e.,
at and below fiber saturation point, drying poten-

tial of the air must exist. It is obvious that when
this drying potential is zero, evaporation of mois-
ture and, therefore, drying will cease.

The capacity of air to hold water vapor increases
rapidly w'ith a rise in temperature. Its drying poten-
tial at any given absolute humidity similarly
increases with increasing temperature.

In sw’elling, the wood absorbs moisture and the
reverse process takes place. The vapor pressure at
the w'ood surfaces is lower than the vapor pressure
of the air. The rate of absorption of moisture by
the wood de]iends largely on the magnitude of the
vapor pressure difference existing.

If a piece of absolutely dry wood is placed in a
completely saturated atmosphere, it will gradually
absorb w^ater vapor from the air up to about 15
percent of its dry weight. In half saturated air
(50% relative humidity), the piece of wood will
absorb half that amount, or 7% percent of its dry
weight. Both the amount of moisture absorbed and
the amount of swelling is, therefore, proportional
to the humidity of the air (Henderson, 1939:67).
It is thus clear that, during evaporation (drying)
and absorption (swelling), the magnitude of the
vapor pressure difference existing at a particular
time is very important.

Shrinkage Due to Grain. — Wood, being aniso-
tropic, has varying shrinkage in all three directions.
,\long the grain of a straight-grained board, shrink-
age is usually negligible for any practical purpose
except in reaction wood. Shrinkage across the
grain, however, is appreciable, even though it is
not uniform.

In the flatsawn or tangential direction, shrinkage
is greater than in the radial direction, the ratio of
shrinkage being generally about 2:1. This ratio
may, however, vary in different species. In addition
to the major wood components, such as vessels and
fibers, which have their axes more or less vertical
in the standing tree, there are the medullary rays,
which run in a radial direction and have axes at
right angles to the fibers. During drying below
fiber saturation point, the rays tend to shrink very
little in length and so tend to restrain the shrinkage
of wood in the radial direction. Hence shrinkage
is less in the direction of the rays than in the direc-
tion of the growth rings.

Shrinkage among Species. — It is a well-known
fact that some woods shrink much more than others

NUMBER 14

Table 1. — Approximate average shrinkage values
from green to oven-dry (data from Forest Product
Research Institute, Kumasi, Ghana)

Terminalia ivorensis (A mire)

Percentage of shrinkage

Radial

Tangential

Tree No. 1*

2.049

3.933

Tree No. 2

1.856

3.996

Tree No. 3

3.407

5.232

Tree No. 4

2.685

5.173

Tree No. 5

Specimen

1.770

3.920

Specimen 2

2.080

3.990

Specimen 3

2.490

3.970

* Tree Nos. I and 2 are from the same locality.

** The specimens were taken at the same level in the tree
but from different positions.

(Tables 1 and 2). Shrinkage also varies from tree
to tree in the same species and in wood taken from
different parts of the same tree. Generally, the
denser the wood, the greater the shrinkage, al-
though there are many exceptions to this rule, e.g.,
the genus Eucalyptus, in which the denser wood
normally shrinks very little, indicating no correla-
tion between density and normal shrinkage.

Any shrinkage figures must be used, however,
with care since this property as indicated above can
be influenced by a number of factors. Even average
figures based on many samples indicate only general
behavior, and not necessarily that of an individual
sample.

Collapse. — Whereas shrinkage implies the nor-
mal contraction of the wood due to loss of moisture,
abnormal shrinkage may be caused by the phenome-
non known as “collapse,” in which, due to very
large liquid tension generated by water leaving the
cell cavity, the cell walls are drawn together or
collapse. The phenomenon can be compared to a
canvas water hose collapsing as the water is emptied
from the hose.

The two phenomena must be recognized as being
distinct, for, whereas normal shrinkage occurs below
the fiber saturation point (25-30% mc), collapse
always occurs at moisture contents high above the
fiber saturation point.

Shrinkage in Reaction Wood. — Shrinkage is also
affected by the presence of growth abnormalities
due to compression or tension. Lumber containing

Table 2. — Approximate average shrinkage values
from green to 12 percent moisture content (data
from FPRL, 1956)

Species and local name

Percentage of shrinkage

Radial

Tangential

Mitragyna ciliata (.Vnura)

3.5

6.5

Afrorinosia elala (Kokrodua)

i.5

2.5

Tristania conferta (Brush Box)

4.0

7.0

Naucl’ea diderrichii (Opepe)

0.9

1.8

Mansonia allissima (Mansonia)

1.5

3.0

Cylicodiscus gabunensis (Okan)

3.0

3.5

compression wood has a great tendency to bend,
twist, and split. Differential shrinkage in the longi-
tudinal direction between norm.al and reaction
wood accounts for this. Compression wood exhibits
extremely high longitudinal shrinkage which may,
in certain cases, reach as high as 6 to 7 percent, as
compared to the negligible amount of shrinkage
(0.1 to 0.2% ) in this direction in normal wood
adjacent to it (Cote, 1965:392).

Pillow and Luxford (1937:17) reported that
radial and tangential shrinkages in compression
wood were less than in normal wood.

Although in tension wood longitudinal shrinkage
is not as great as in compression wood, it may be
as high as 1 percent, which is considerably higher
than the longitudinal shrinkage of normal wood.
Another industrial problem related to the seasoning
of tension wood from the green condition is col-
lapse (Dadswell and Wardrop, 1955). Some species
have a greater tendency to collapse than others, but
this tendency is always increased by the presence
of tension wood.

The Measurement of Shrinkage. — Wood shrink-
age is expressed as a percentage of its green size in
the tangential, radial, and longitudinal directions
when dried to a particular moisture content (mc).
The standard method is to calculate the shrinkage
when the wood is dried to 12% mc or to the oven-
dry condition (0% mc). Shrinkage is sometimes
also expressed on a volumetric basis, that is, as a
percentage loss of the original volume.

Let us consider the following examples: Suppose
a flatsawn board measured 20 cm long when green,
and when dried to 12% mc it measured 19 cm. The
percent shrinkage would be as follows:

SMITHSONIAN CONTRIBUTIONS TO BOTANY

loss in si/e

green size (original size)

X 100%,

20 - 19 cm

which will be 20~cm ^ ^ ’00%’

= 1

X 1007c

= 3% at 12%

MC.

Suppose in drying to 0% mc the size reduced further
to 18.5 cm. Percent shrinkage at oven-dry would
then be

that is

loss in size

green size (original size)
20 — 18.5 cm

X 1007c

20 cm

= 1.5

^ X 100%

X 1007c

= 7.5% at 0% MC.

In determining volumetric shrinkage the same prin-
ciple applies. Usually the measurements of the
three dimensions of a block of wood are taken
using the vernier callipers at green and also at 12%
MC or oven-dry. The volumes at both conditions
(i.e., at green and at 12% mc or oven-dry) are cal-
culated, and then the percent shrinkage determined
as before. Sometimes the volume is determined by
the amsler volume meter.

Since longitudinal shrinkage of a normal wood
is negligible, approximate volumetric shrinkage of
a piece of wood may be determined by adding
together the tangential and radial percentage
shrinkages.

Descriptions of Species Arranged by Families

PLATES 1-28

The top center portion of each plate represents the cross-section of the
wood. Lower left: longitudinal tangential. Lower right: longitudinal radial.

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 1

ANACARDIACEAE

Antrocaryon micraster A. Chevalier & A. Guillaumin

Standard trade name: Antrocaryon
Local name; Aprokuma (Ghana)

A common, large, dry closed-forest tree growing
up to 150 ft high and 7-9 ft in girth. In Ghana,
antrocaryon is quite common along the northern
edge of the high forest zone. It is also present in the
southern portion of the Boumfum Forest Reserve
along the Kwahu Scarp and in the Worobong For-
est Reserve. Its distribution ranges from Sierra
Leone to the Cameroons. The leaves are terminal
with entire, acuminate, pinnate leaflets in 9 or 10
opposite pairs. The flowers are small, numerous,
and greenish white.

General Description. — The sapwood is greenish
to yellowish white and the heartwood is grayish
pink to reddish brown. The planed surface is lus-
trous. The texture is described as medium and it is
straight-grained. The wood has neither a distinct
taste nor odor. The air-dried wood is light weight
and has an average weight of 31 Ib/ft®.

Seasoning. — This wood dries quite rapidly with
slight distortion. British Forest Products Labora-
tory kiln schedule L is recommended (eprl, 1956).

Durability. — The wood is not very durable and
is also easily impregnated.

Working Qualities. — Although the wood is
woolly when sawed, it generally works well with
hand and machine tools. Nail and screw-holding

qualities are good. The wood takes glue and
responds to finishing treatments well.

Uses. — The timber is used for planks and for
furniture. It is also used for the preparation of
packing cases.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels; solitary but with a few radial
multiples of 3 to 5 small pores; circular in out-
line, rarely angular; average pore diameter 196|.im,
range 112pm-238pm; average vessel element length
560j.im, range 366pm-666|.im; vessel wall thickness
3|.im-4|,im; perforation plates exclusively simple;
vessel element end wall inclination slightly oblique
to transverse; intervascular pitting alternate, rather
large. Imperforate tracheary elements: septate fiber
tracheitis, average length 1269|.im, range 966pm-
1 165pm; fibers with very few simple pits on tan-
gential walls. Vascular rays: heterogeneous, mainly
multiseriate, generally 3 cells wide, 5 to 20 cells
high, but biseriate and uniseriate cells also present;
fusiform rays up to 10 cells wide containing inter-
cellular canals. Axial parenchyma: paratracheal,
scanty, cells containing dark amorphous deposits.
Crystals: abundant, generally cubiodal, present in
ray cells as well as in fibers. Special note: Inter-
cellular canals occur in some rays.

NUMBER 14

PLATE 1

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 2

BURSERACEAE
Canarium schweinfiirthii Engler

Standard trade name: Canarium

Local names: Bediwunua (Ghana) , Abel (French West Africa) , Elcmi (Nigeria)

An evergreen and decidiions forest tree growing to
120-160 ft high and 12-15 ft in girth. Although the
trees are not very common, they can be found in
the high forest zone and in the savanna-woodland.
They are often located in the Antiaris-Chlorophnra
association. The leaves are pinnate, oblong or
oblong-lanceolate, acuminate, generally in terminal
whorls. The flowers are creamy white and are borne
in axillary panicles.

General Description. — The sapwood is whitish,
up to 3-4 in; the heartwood is pale pink darkening
to light brown. The surface is highly lustrous and
the wood is highly scented, especially when it is
freshly cut. The texture is somewhat coarse and
sometimes may appear woolly. The grain is often
interlocked. The wood is light to medium, weighing
31-38 Ib/ft averaging 33 Ib/ft w'hen seasoned.

Seasoning. — This wood dries quite easily either
when air seasoned or kiln dried. Because of a ten-
dency to warp, it is recommended that initial
exposure should be at low temperatures.

Durability. — The wood is not very durable since
it is easily attacked by pinhole borers and powder-
post beetles. It is very resistant to impregnation,
especially the heartwood by the open-process, but
the sapwood is fairly permeable.

Working Qualities. — The wood is not very dif-
ficult to work when sharp edged tools are used.
Sawimj difficulties are encountered because of the

presence of silica. The wood cuts well with rotary
and veneer machines. It has good nail-holding prop-
erties and can be easily glued. Planing is compara-
tively easy and when the wood is brought to a good
surface it takes a high polish.

Uses. — With an average exploitable girth of 8-10
feet, the wood is used for flooring, interior joinery,
and furniture. Quarter-sawn material presents a
decorative surface which, when suitably stained,
can serve as a substitute for mahogany.

Xylem Anatomy.^ — Growth rings absent. Wood
diffuse-porous; vessels mostly solitary or in radial
multiples of 2 or 3 pores; elliptical to circular in
outline; average pore diameter 210pm, range 98pm-
280pm; average vessel element length 420pm, range
221pm-630pm; vessel wall thickness 2pm-4pm;
perforation plates exclusively simple; vessel element
end wall inclination slightly oblique to transverse;
intervascular pitting alternate, apertures somewhat
elliptical or slit-like. Imperforate tracheary ele-
ments; septate libriform fibers, average length
1540pm, range 1313pm-1875pm. Vascular rays:
heterogeneous, mainly multiseriate, generally 3 cells
wide, 9 to 20 cells high, few biseriate. Axial
parenchyma; paratracheal, sparse, usually 1 or 2
cells ensheathing vessels. Tanniniferous substances:
observed in ray cells as well as parenchyma cells.

Crystals. — Cuboidal, many, present in ray cells
as well as fibers.

NUMBER 14

PLATE 2

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 3

COMBRETACEAE
Terminalia ivorensis A. Chevalier

Standard trade name: Idigbo

Local names: Amire (sometimes wrongly written “emeri”) (Ghana), Framire (Ivory Coast)

A closed-forest tree growing up to 150 ft high
and 15 ft in girth. Buttresses blunt and extending
up the bole, which is frequently narrowly fluted.
Leaves are obovate, acuminate and fairly puberu-
lous. Flowers are in slender racemes 4-5 in long.
They are white and fragrant.

General Description. — The light-weight timber
has pale yellow to light brown sapwood with the
heartwood slightly darker. The sapwood is usually
1-2 in thick. The grain of the timber is fairly
straight but sometimes slightly interlocked. The tex-
ture is medium to coarse and the growth rings
unusually distinct for a tropical timber. The weight
varies between 30 and 39 Ib/ft ^ and the average is
about 34 Ib/ft ^ seasoned. The green weight may be
about 50 Ib/ft A

Seasoning. — The timber is known to season
rapidly and well with little or no checking. British
Forest Products Laboratory kiln schedule J gives
good results (eprl, 1956).

Durability'.- — Idigbo is durable. The sapwood is
susceptible to attack by powder-post beetles. Data
on its resistance to termite attack in West Africa
are conflicting.

Working Qualities. — The timber works fairly

easily with all hand and machine tools, having only
a small blunting effect on their cutting edges. It
finishes cleanly in other operations and stains and
jiolishes well if the grain is suitably filled. It takes
nails and screws well. It also glues satisfactorily.

LhsES. — The timber, which is weather resistant, is
used for house building, shingles, greenhouses,
furniture, paneling, cabinet and interior work. It
may also be used for plywood manufacture.

Xylem Anatomy. — Growth rings present. Wood
ring-porous. Vessels: solitary or in pairs, rarely in
threes; circular in outline, rarely angular; average
pore diameter 119pm, range 40pm-160pm; average
vessel element length 444pm, range 300pm-575pm;
vessel wall thickness 3pm-4pm; perforation plates
simple; vessel element end wall inclination slightly
oblique to transverse; intervascular pitting alter-
nate, rather small. Imperforate tracheary elements;
nonseptate fiber tracheids, average length 1185pm,
range 1000pm-1375pm; fibers with very few simple
jiits on tangential walls. Vascular rays: homogene-
ous, primarily multiseriate, 3 cells wide, 3 to 27
cells high, biseriate and uniseriate cells also present.
Axial parenchyma: paratracheal, cells containing
dark, amorphous deposits.

NUMBER 14

PLATE 3

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 4

COMBRETACEAE
Terminalia siiperba Engler & Diels

Standard trade name: Afara

Local names: Ofram (Gliana) , Akom (Cameroons) , Limbo, Chenedimbo, Frake, Noyer dii Mayombe (French-speaking West

Africa), Ka-ronko (Sierra Leone), Afara, Eji, Edo, Ojiloko (Nigeria)

A forest tree growing to 150 ft (rarely to 200 ft)
high, with large, thin buttresses, a clean, straight
bole, and a rather flat crown; bark ashy gray. Plants
in the family Combretaceae are recognized by their
exstipulate simple leaves, inferior ovary and often
winged fruits.

General Description. — The timber is grayish
white or light yellowish brown with no distinct
demarcation between heartwood and sapwood.
Depending on locality, some woods have dark
walnut-brown zones in the center. Therefore, the
timber is divided into two groups depending upon
the proportion of the log containing the dark
coloration.

“Limba clair” or “White afara” is the term
applied to timber with little or no dark coloration
and “Limba noir” or “Dark afara” is applied to
logs with extensive dark colored wood. The wood
varies in weight. The recorded range is 25-49 lb/
ft 3, seasoned, and the green weight is about
55 Ib/ft 3.

Seasoning. — Although seasoning properties are
not fully known, it is believed to kiln-season simi-
larly to Terminalia ivorensis. The wood is com-
monly straight-grained.

Durability. — Nondurable. Both sapwood and
heartwood are susceptible to pin-hole borers; the
sapwood is also susceptible to powder-post beetle
attack. Preservative treatment in Nigeria indicates

that afara is resistant to penetration of creosote by
the open tank method but less resistant to treatment
with aqueous solutions.

Working Qualities. — Generally the working
properties of the wood are good. The straight-
grained wood machines easily without pick-up. It
holds nails and screws firmly, although there is
sometimes a tendency to split. It is reported to
have satisfactory veneer-cutting qualities by either
the rotary or slicing methods. Afara finishes and
glues well.

Uses. — Afara is used for furniture, school furnish-
ings, shop fittings, and joinery. It has been tried
as railway cross-ties in Ghana and has proved
satisfactory.

Xylem Anatomy. — Giowth rings present. Wood
diffuse-porous. Vessels: solitary but with a few radial
multiples of 2 to 5 pores; circular or ovate in out-
line; average pore diameter 175pm, range 150pm-
250pm; average vessel element length 703pm, range
433pm-866pm; vessel wall thickness averages 6.0pm;
perforation plates simple; vessel element end wall
inclination mostly slightly oblique; intervascular
pitting alternate. Vascular rays: homogeneous,

uniseriate, varying greatly in height, 2 to 25 cells
high. Imperforate tracheary elements: fiber tra-
cheids, average length 1645pm, range 1432pm-
1998pm, without pits. Axial parenchyma: apotra-
cheal, banded, abundant.

NUMBER 14

PLATE 4

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 5

LECYTHIDACEAE

Comhretodendron macrocarpum (Palisot de Beauvois) Keay

(Syn. C. africanurn Welwitsch ex Bentham)

Standard trade name: Essia
Local name: Esia (Ghana)

A tree up to 150 ft high, usually 3 ft in diameter
with a 12 ft girth around the buttressing. The tree
displays a well-developed crown and a straight bole
with buttresses. The leaves are 6X3 inches,
obovate, and glabrous, with shallowly serrate mar-
gins. The white flowers are abundant in short,
axillary racemes.

General Description. — The reddish brown
heartwood is clearly delineated from the pale white
sapwood, which is 3 in or more thick. Essia has a
powerful, unpleasant odor when freshly felled. It
is hard and heavy, weighing about 44-50 Ib/ft ^
seasoned and about 611 Ib/ft ^ green. The grain is
interlocked and the texture medium.

Seasoning. — Dries slowly and very prone to check
and split.

Durability.- — Moderately resistant. Damage by
ambrosia beetles is sometimes present. The sap-
wood is permeable but the heartwood is extremely
resistant to preservative treatment.

Working Qualities. — The timber is hard to work
with hand and machine tools, but logs are sawed
with little difficulty. The wood planes to a smooth
finish using a 20° cutting angle. It does not take
nails easily and requires prebored holes. It glues
satisfactorily and takes stains effectively. It polishes
to a satisfactory finish when a filler is used.

Uses.— Used locally for heavy and general con-
struction work by the mining companies. It is not
suitable for peeling.

Xylem Anatomy. — Growth rings absent. Wood is
diffuse-porous, as in many tropical woods. Vessels:
solitary and multiples of two to eight, minute pores
which are circular to ovate in shape with a few
irregularly angular. Average pore diameter 68pm,
range 18pm-89pm; average vessel element length
435pm, range 340pm-600pm; vessel wall thickness
3pm-4pm; perforation plates exclusively simple;
vessel element end wall inclination is oblique to
transverse with intervascular pitting alternate and
small.

NUMBER 14

PLATE 5

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SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 6

LEGUMINOSAE

Copaifera salikounda Heckel

Standard trade name: Bubinga
Local name: Entedua (Ghana)

The tree grows to a height of about 140 ft and
has a 9 ft girth; bark fibrous and wrinkled, leaves
pinnate, leaflets 12-14, elliptic, sides unequal,
emarginate at tip, shining surfaces, slender lateral
nerves numerous. Flowers conspicuous and in sim-
ply branched panicles. Fruits are brownish, woody,
Hat and oval shaped.

General Description. — The wood is very hard
and heavy. The heartwood is light reddish brown
or darker in color veined with pink or red stripes.
I'he sapwood is paler. The grain is often inter-
locked or wavy producing fine figures. The seed
after the removal of the wavy red aril has an
aromatic odor, especially when dry. The bark and
the wood also give off a similar odor.

Seasoning. — The wood seasons slowly and would
require mild drying conditions.

Durability. — Durable, but sapwood is susceptible
to attack by insect borers. Little is known about
its preservative qualities.

Working Qualities. — Works well with hand and
machine tools though it has a tendency to chip off

and to blunt their cutting edges. Glues and polishes
well. It is advisable to prebore before nailing and
screwing.

Uses. — Copaifera produces beautiful veneer for
paneling, fine furniture and cabinets.

Xylem Anatomy. — Growth rings marked by
bands of parenchyma. Wood diffuse-porous. Vessels:
about half solitary, half radial multiples, of 2 to 5
pores, but mostly 2; frequency about 2-4 per mm^.
Average pore diameter 202pm, range 142pm-265pm,
average vessel wall thickness about 4pm-8pm; per-
foration plates simple. Intervascular pitting alter-
nate, pit aperture slit-like, included. Intervascular
spaces filled with gum. Vascular rays: homogeneous
multiseriate, generally 2 or 3 cells wide, average
length about 427pm, range 258pm-727pm. Axial
parenchyma: paratracheal, vasicentric, rarely ali-
form, terminal bands about 5 to 10 cells wide
concurring with intercellular canals. Fiber cells
radially arranged; crystals present; chambered cells
containing about 4 to 10 diamond-shaped crystals.

NUMBER 14

PLATE 6

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 7

LEGUMINOSAE

Cylicodiscus gabunensis (Taub) Harms

Standard trade name: Okan

Local names: Denya (Ghana), Imbeli-deli (Sierra Leone), Bouc'mon (I\ory Coast), Olosan, Okan, (Nigeria), Adum (Cameroons)

This large tree has a clear bole about 120 ft high
and about 10 ft in diameter. Crown somewhat flat,
wide-spreading, and fairly open. Buttresses short,
slash ])ale yellow, stringy, giving an offensive smell.
Young bark ashy white turning reddish brown or
almost black, rough and scaly later. Saplings have
brown thorns on the stems. Leaves bipinnate, pin-
nae 1 pair, opposite, leaflets alternate, ovate, long-
pointed, glabrous above, reddish on young seedling
trees. Flowers small, numerous, yellowish or green-
ish white, in slender spike-like and paired racemes
up to 6 in long; stamens 10. Fruits up to 3 ft X
1% in, yellow at first, turning brown, with irregular
longitudinal raised nerves and covered with rusty
scales; seeds flat, up to 3 in or more long, thinly
winged.

General Description. — The sapwood, 2-3 in
wide, is pinkish and the heartwood is yellow-brown
with dark brown or reddish brown streaks. The
wood is exceedingly heavy, averaging about 591
Ib/ft air dry, and about 781 Ib/ft green (45%
Mc). The grain is typically interlocked, and the
texture moderately coarse.

Seasoning. — Okan seasons slowly with a marked
tendency to split and check. British Forest Products
Laboratory kiln schedule B is recommended (fprl,
1956).

Durability. — Okan is rated very durable. The
sapwood is susceptible to attack by powder-post

beetles (Bostrychidae and Lyctidae). It is extremely
resistant to preservative treatment. The sapwood is
also resistant.

Working Qualities. — The timber is very hard
and difficult to cut with machine and hand tools
and dulls their cutting edges fairly quickly. The
pronounced interlocked grain makes it difficult to
obtain a clean finish in a number of operations.
Okan stains and polishes satisfactorily but requires
preboring before nailing.

Uses. — It is most suitable for piling and wharf
decking as it can be used without preservative
treatment. Its resistance to wear is very high and
it is recommended for heavy-duty flooring in fac-
tories and warehouses. Its density and interlocked
grain make it unsuitable for plywood manufacture.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: mostly solitary, occasionally
in multiples of 2 or 3, oval in outline; average pore
diameter 224|.un, range 168|_un-322pm; vessel wall
thickness 4pm, perforation plate simple; vessel ele-
ment end wall inclination slightly oblique to trans-
verse; intervascular pitting alternate. Imperforate
tracheary elements: fiber tracheids, average length
420pm, range 294pm-630pm. Vascular rays: pre-
dominantly biseriate but with few uniseriate, bi-
seriate rays 8 to 55 cells high, uniseriate rays 5 to 15
cells high. Axial parenchyma; paratracheal, some-
times vasicentric, conspicuously banded. Tannini-
ferous material present in some vessels and ray cells.

NUMBER 14

PLATE 7

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 8

LEGUMINOSAE

Distemonanthus benthamianus Baillon

Standard trade name: Ayan

Local names: Barre (Tvory Coast), Dua anyan, Bonsamdia (Ghana), Ayan, Anyaran, Edo (Southern Nigeria), Basong

(Cameroons) , Oqueminia (Gabon)

A tall slender tree over 100 ft high and about 21/9
ft in diameter. The bole is reasonably straight and
cylindrical. Ayan occurs in the rain forests. It has
weakly developed buttresses. The bark is smooth
and shining, dark green with a reddish tinge when
young, turning orange or red later. The bark peels
oft in large patches. Leaves pinnate, leaflets 9-11,
ovate-lanceolate, alternate, acuminate, with numer-
ous consjiicnons lateral nerves. Flowers in loose
panicles, creamy white and red or pinkish, sepals
5, pinkish brown and unequal, 3 narrow petals,
papery in texture, unequal, longer than sepals, 2
fertile stamens. Fruit pods reddish brown, hairy
when young. Single-seeded, seeds small and brown.

General Description. — The narrow sapwood is
creamy and the heartwood dull yellow or yellowish
brown. The wood is highly lustrous and finely tex-
tured. The grain is commonly irregular and inter-
locked. Ayan is hard and moderately heavy, ranging
from 37-181 Ib/ft ^ averaging about 421 Ib/ft'^
seasoned. The wood often contains a yellow ex-
tract, 'which under most conditions acts as a
direct dye on clothing. It is readily bleached by
hypochlorites.

Seasoning. — The timber seasons satisfactorily,
but not rapidly. It has a tendency to split or
warp. The British Forest Products Laboratory kiln
schedule F is suggested (fprl, 1956).

Durability. — Ayan is moderately durable. It is
moderately resistant to preservative treatment.

Working Qualities. — The timber works well

with all tools, though tending to blunt them. It is
liable to pick-up under the jrlane. It finishes cleanly
in most operations but tends to char when bored.
Some specimens contain a high proportion of silica.
Such material can only be sawed satisfactorily wfith
teeth tipped with tungsten carbide. In planing and
molding, tearing occurs on quarter-sawn material
but a reduction of the cutting angle to 20° usually
insures a clean surface. It has some tendency to split
when nailed. It takes stain and polish well, requir-
ing only a moderate amount of filler.

Uses. — Ayan is a useful joinery and cabinet tim-
ber. It is also used for door-frames, windows and
sills, interior decoration, turnery, and furniture.
For flooring it is suitable for domestic buildings.
It is also used for lorry bodies. As it stains fabrics
it is not suitable as a draining board.

XvLEM Anatomy'. — Growth rings absent. Wood
diffuse porous. Vessels: mainly solitary and multi-
ples of 2 or 3; average pore diameter 195|.im, circular
in outline; average vessel length 294pm; range
252pm-308pm; vessel wall thickness 8pm; perfora-
tion plates simple. Vessel end wall inclination
slightly oblique to transverse; intervascular pitting
alternate, small. Imperforate tracheary elements:
fiber tracheids, few, septate; average length 350pm,
range 308pm-490pm. Vascular rays: heterogeneous,
mostly multiseriate, 3 or 4 cells wide, 5 to 15 cells
high. Axial parenchyma: paratracheal, moderately
abundant, tendency towards aliform but generally
banded. Tanniferous material present in vessels.

NUMBER 14

PLATE 8

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 9

MELIACEAE

Entandrophragma angolense (Welwitsch) A. C. DeCandolle

Standard trade name: Gedu nohor

Local names: Edinam (Ghana), Gedu lohor, Gedu noha (Nigeria), Tiama (France and Ivory Coast.)

A deciduous forest tree growing to 160 ft tall with
a clean bole up to 80 ft in height, girth of 15 ft
above buttresses; bark smooth, pale gray-brown with
pinkish or rusty orange patches; leaves alternate,
exstipulate, paripinnate; inflorescence a large, lax
panicle; flowers small, greenish white, scented.

General Description. — The heartwood is typ-
ically dull reddish brown and the light colored
sapwood is about 4 in wide. Gedu nohor is of plain
appearance compared to sapele but very similar to
the African mahoganies. It is medium hard and
medium heavy, varying in weight from 32-36 Ib/ft ^
(average about 34 Ib/ft^) when seasoned and about
51 Ib/ft ^ green. The surface is lustrous. It has no
distinct odor or taste.

Seasoning.— Gedu nohor seasons fairly rapidly
with a tendency to distort. The British Forest Prod-
ucts Laboratory kiln schedule A is recommended
(fprl, 1956).

DtRABiLiTY. — The wood is moderately durable.
Damage by ambrosia beetles is occasionally present.
It has been recorded in Nigeria as moderately
resistant to preservative treatment.

Working Qualities. — Works fairly easily with
machine and hand tools. It planes and turns well.

but may have a tendency to pick-up on the quarter.
It bores and takes nails and screws well. Gluing is
satisfactory.

Uses. — Its uses are similar to sapele. Being a
decorative timber, it is used for paneling, interior
and decorative work, furniture and superior joinery.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous rarely. Vessels: solitary or in radially
oriented groups of 2 or 3, pores circular in outline;
average pore diameter 82pm, range 45pm-110pm;
average vessel element length 556pm, range, 400pm-
900pm; vessel wall thickness 4pm; perforation plates
not seen; vessel element end wall inclination trans-
verse; intervascular pitting alternate, pits ca.
1.25pm. Imperforate tracheary elements: septate
fiber tracheitis with dark amorphous substance in
some; average length 1798pm, range 1375pm-
2225pm; pits moderately abundant, only on radial
walls, slits extending beyond pit boundary. Vas-
cular rays: heterogeneous, multiseriate (only 1
uniseriate ray seen), 3 or 4 cells wide, 20 to 39 cells
high including tails, which are 1 or 2 cells in length.
Axial parenchyma: apotracheal, bands 2 or 3 cells
wide; also paratracheal, vasicentric and somewhat
aliform.

NUMBER 14

PLATE 9

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 10

MELIACEAE

Entandrophragma candollei Harms
Standard trade name: Omu

A huge evergreen and deciduous forest tree
growing up to 200 ft high and 23 ft in girth. The
leaves are terminal with pinnate leaflets in 6 to 8
opposite to subopposite pairs, up to 3.5 in long,
oblong elliptic or oblong-ovate with a rounded
apex. Leaf base rounded or sides slightly unequal,
conspicuous parallel reddish nerves below, rachis
and buds brownish tomentose. The flowers are
yellow in short pubescent panicles.

General Description. — The heartwood is dark
red-brown in color and is distinct from the pinkish
red sapwood. It is hard and of medium weight
which averages about 39 Ib/ft ^ seasoned. Green
weight is about 60 Ib/ft It has an even, medium
to coarse texture. The grain is generally interlocked.

Seasoning. — Omu seasons very slowly with a
marked tendency to distort. The British Forest Prod-
ucts Laboratory kiln schedule A is recommended
(fprl, 1956).

Durability. — Moderate.

Working Qualities. — Gompared to sapele, omu
is more difficult to saw, but works easily with ma-
chine and hand tools. It has a tendency to tear in

planing and molding. For the best finish, therefore,
a cutting angle of about 20° should be employed.
It takes nails, stains, and polishes well.

Uses. — As a superior timber, omu produces
beautiful veneer for paneling, furniture, cabinets,
and fine interior woodwork. It is employed for
flooring and is moderately to highly durable.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: about half in radial multi-
ples of 3 to 8 pores, and about half solitary; solitary
pores circular in outline, smaller pores in chains,
usually angular; average pore diameter 82.4pm.
range 40pm-140pm; average vessel element length
690pm, range 538pm-850pm; vessel wall thickness
2pm-3pm; perforation plate simple; vessel element
end wall inclination slightly oblique to strongly
oblique, few transverse; intervascular pitting alter-
nate, relatively small. Imperforate tracheary ele-
ments: nonseptate fibers, average length 1255pm,
range 1 130pm-2325pm. Vascular rays: heterogene-
ous, mostly multiseriate, generally 4 or 5 cells wide,
1 1-24 cells high, but a few biserate cells also present.
Axial parenchyma; apotracheal, banded, cells with
dark amorphous deposits. Crystals absent.

NUMBER 14

PLATE 10

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 11

MELIACEAE

Entandrophragma cylindricum Sprague

Standard trade name: Sapele
Local name: Penkwa (Ghana)

A tree about 180 ft with a cylindrical, straight
clean bole 80-100 ft high. The average diameter is
about 3-4 ft but diameters of up to 20 ft have been
reported (Dalziel, 1937:320; Kennedy, 1936:176).
Buttresses are broad and low. Leaves up to 20 in
long, pinnate, leaflets 6 to 9 pairs, opposite or sub-
opposite, 6 X 3 in, lateral nerves 6 to 12 pairs,
prominent below, hairs only in axils. Starlike
flowers are yellowish white, small and numerous.
Fruit capsules cylindrical and pendulous.

General Description. — The sapwood is pale in
color with a pinkish tint; the heartwood being more
reddish when freshly cut, darkening to rich red-
brown when exposed. The most striking feature of
sapele is the regular stripes on the quarter-sawn
lumber or veneer. Logs with wavy grain yield highly
decorative veneers. The texture is fine to medium.
The average weight is about 391 Ib/ft^ seasoned,
and usually ranges between 35 and 431 Ib/ft The
green weight is about 551 Ib/ft The wood is
harder and heavier than African mahogany.

Seasoning. — The wood dries slowly thus requir-
ing mild drying conditions and good stacking prac-
tices. The wood has a marked tendency to warp.

Durability. — Moderately durable. The sapwood
is susceptible to attack by powder-post beetles
{Lyctidae and Bostrychidae) and termites. It is
resistant to impregnation.

Working Qualities. — Sapele works fairly easily
by hand and machine tools with relatively little
dulling effect on their cutting edges. Material with
interlocked grain is often troublesome to plane
and mold as it causes picking-up of quarter-sawn
surface and also some chipping out. However, with
a cutting angle of 15° uniformly good results
are achieved. It takes nails, screws and glues
satisfactorily and finishes well.

Uses. — Suitable for uses to which omu (E.
candollei) is applied, that is, superior joinery,
cabinet work, furniture, and flooring.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: about one-fourth solitary,
rest in clusters or sometimes radial multiples of 2
or 3 pores, solitary pores more or less circular in
outline; average pore diameter 168pm, range 98pm-
182pm; average vessel element length 420pm, range
252pm-560pm; vessel wall thickness 4pm-8pm;
perforation plates simple; vessel end wall inclina-
tion slightly oblique to almost transverse; inter-
vascular pitting alternate, very small. Imperforate
tracheary elements: septate fibers present with
scanty, simple pitting on radial walls. Vascular
rays: homogeneous multiseriate, generally 2 to 4
cells wide, tendency towards storied arrangements.
Axial parenchyma: apotracheal, banded with dark
amorphous deposits. Crystals present, rectangular,
often embedded at ends of rays.

NUMBER 14

PLATE 11

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 12

MELIACEAE

Entandrophragma utile (Dawe & Sprague) Sprague
Standard trade name: Utile

A large tree of moist-dry to dry closed forests
growing up to 210 ft high and 25 ft in girth. The
deciduous leaves are pinnate, up to 30 in long, the
leaflets 12 pairs or more, up to 6 in long, shortly
acuminate or rounded at apex. The flowers are
whitish, in terminal inflorescences.

General Description. — Seasoned, the average
weight is about 42 Ib/ft ^ and the green weight
about 50 Ib/ft The rich, red-brown timber resem-
bles sa])ele, but lacks the cedar-like scent of the
latter. The sapwood is distinct from the heartwood
and is light brown in color. Utile has broad, inter-
locked grain and produces a stripe figure on the
quarter-sawn lumber.

Seasoning. — It seasons at a moderate rate with a
definite tendency for original shakes to extend dur-
ing drying. British Forest Products Laboratory kiln
schedule A is recommended (fprl, 1956).

Durability. — Utile is moderately resistant to
insect attack. The sapwood is, however, liable to
attack by powder-post beetles. It is resistant to
preservative treatment.

Working Qualities. — Utile works fairly readily
with hand and machine tools and has a compara-
tively small blunting effect on their cutting edges.

It takes nails and glues satisfactorily, stains readily
and polishes well after the grain has been suitably
filled.

Uses. — It is similar to omu (E. candollei) in its
general uses, but is rather less suitable for decorative
work. It is mainly used for interior furniture, truck
frames, door frames, and for interior joinery and
fittings. It is a good source of rotary-cut plywood.

XvLEM Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: solitary, or often in multi-
ples of 2 to 4, tyloses present, circular in outline,
rarely angular; average pore diameter 225pm, range
80[.im-250pm; average vessel element length 636pm,
range 413pm-788pm; vessel wall thickness about
6|im; perforation plates simple; vessel element end
wall inclination transverse to slightly oblique;
intervascular pitting alternate. Imperforate trache-
ary elements: septate fibers present with scanty,
simple pitting on radial walls. Vascular rays: homo-
geneous, biseriate, occasionally multiseriate or
uniseriate, 5 to 20 cells high. Axial parenchyma:
paratracheal, abundant, in multiseriate tangential
bands, occasionally uniseriate; stained amorphous
deposits in most. The wood is an advanced one.

NUMBER 14

PLATE 12

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 13

MELIACEAE

Guarea cedreta (A. Chevalier) Pellegrini

Standard trade name: Scented Guarea

Local names: Kwabohoro (Ghana) , Bosse (France & Ivory Coast) , Obobonufua (Nigeria)

A heavily buttressed tree up to 160 ft tall and
up to 8.5 ft in girth; bole clear, considerably fluted
at the base; crown dense; bark silvery gray; leaves
pinnate with 4 to 6 pairs of leaflets; flowers green,
with few-flowered inflorescences.

General Description. — Guarea is medium hard
and of medium weight, about 36 Ib/ft^ seasoned
and about 60 Ib/ft ^ green. The pinkish brown
heartwood is like pale African mahogany. The sap-
wood is lighter in color than the heartwood. Freshly
sawn, guarea has a strong cedar-like scent, which
tends to disappear on exposure. The timber has a
medium-fine texture and a high luster. The grain
may be straight or wavy, and a mottled or curly
figure may be present.

Seasoning. — The timber appears to season fairly
rapidly with very little degrade. Resin exudation
may cause some degrade in the appearance of the
wood. The British Forest Products Laboratory kiln
schedule E has given satisfactory results (fprl, 1956).

Durability. — Moderately durable, but damage by
ambrosia beetles is sometimes present. It is ex-
tremely resistant to preservative treatment. The
sapwood is permeable.

Working Qualities. — Generally it saws and
planes fairly easily. It works satisfactorily with hand
and machine tools, but dulls their cutting edges.

There is a slight tendency to pick-up in planing
quarter-sawn material, but generally a good finish
is obtained in most operations. It takes nails and
screws well and stains readily. Polishing, however,
needs care because of possible resin exudation.

Uses. — Guarea is a superior joinery timber and
is used for furniture, interior fittings, boats and
vehicles, as well as for good quality plywood and
decorative veneer.

Xylem Anatomy. — Growth rings present. Wood
diffuse-porous. Vessels; solitary to groupings of 3,
rarely more; average pore diameter 122pm; circu-
lar to narrowly elliptical in outline; average vessel
length 536pm, range 300pm-788pm; vessel wall
thickness 5pm; perforation plates, unable to deter-
mine with certainty but they appear simple. Vessel
end wall inclination transverse to oblique; inter-
vascular pitting alternate, simple, small and numer-
ous. Imperforate tracheary elements: septate fiber
tracheitis; average length 1668pm, range 1325pm-
2000pm. Vascular rays; homogeneous, generally one
cell in thickness, but frequently with 2 or 3 small
cells abreast. Axial parenchyma: apotracheal,

banded, moderately abundant pitted. Crystals and
inclusions: no crystals apparent; however, some
ray cells contain dark staining deposits.

NUMBER 14

PLATE 13

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 14

MELIACEAE

Khaya grandifolia A. C. DeCandolle

Standard trade name: African mahogany, which is also applied to K. anthotheca and K. ivorensis

A common tree of dry closed forests growing up
to 130 ft high and up to 28 ft in girth. The leaves
are about 16 in long, pinnate, shining, with leaflets
up to 14 pairs, plus a terminal leaflet, 10-12 in X
5 in, elliptic to ovate-elliptic, the tips shortly
acuminate. The flowers are numerous, in axillary
panicles 8-10 in long. The wood is used as a
substitute for true mahogany (Swietenia mahogani).

General Description. — Khaya grandifolia tends
to be a little darker and appreciably heavier than
K. ivorensis, the weight per cubic foot averaging
about 44 Ib/ft ^ seasoned. The heartwood is reddish
brown; it is pinkish white when freshly felled. It is
not always easy to spot the demarcation line be-
tween sapwood and heartwood when freshly felled.
The grain is usually interlocked, but some of the
timber is fairly straight-grained. The texture is
medium to coarse.

Seasoning. — Like all African mahoganies, it gen-
erally seasons fairly rapidly with little degrade.

Durability. — It is moderately durable and ex-
tremely resistant to preservative treatment.

Working Qualities. — The timber works fairly
easily with hand and machine tools. Generally its

dulling effect on cutting edges is relatively small.
When planing quarter-sawn material, and especially
when the grain is interlocked, a reduction in cutting
angle to about 15° is advisable to avoid pick-up.
The timber has good nailing, screwing, and glue-
ing qualities. It responds well to usual finishing
treatments. It glues satisfactorily.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: mainly in two’s, but range
from 1 to 4; oval in outline, sometimes circular;
average pore diameter 71.5pm, range 50pm-90pm;
average vessel element length 564pm, range 350pm-
763pm; vessel wall thickness undetermined; perfora-
tion plates simple; ves.sel element end wall in-
clination slightly oblique; no intervascular pitting.
Imperforate tracheary elements: septate fiber tra-
cheids; average length 1893pm, range from 1638pm-
2250pm; fibers with numerous pits. Vascular rays:
homogeneous, multiseriate, generally 3 to 5 cells
high, but unseriate and biseriate rays present, no
fusiform rays. Axial parenchyma: paratracheal,
numerous, cells containing amorphous deposits.
Crystals: none present.

NUMBER 14

PLATE 14

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 15

MELIACEAE

Khaya ivorensis A. Chevalier

Standard trade name: African mahogany, which is also applied to K. anlhotheca and K. grandifolia

A dominant tree, up to 200 ft high and 15 ft in
girth above the large buttresses, with long clear bole
up to 90 ft. It is a rain-forest tree found in low-lying
grounds in West Africa.

General Description. — The timber is medium
hard and has a medium weight varying between 32
and 45 Ib/ft The average weight is about 35
Ib/ft ^ seasoned. The green weight is about 44
Ib/ft^. The sapwood is about 2 in wide and the
color is yellowish brown. The timber has a simi-
lar, if not the same, general description as K.
gra7jdifolia and the other African mahogany species.

Seasoning. — All the species of African mahogany
season fairly rapidly and well with little degrade.

Durability. — Logs are susceptible to attack by
pin-hole borers and powder-post beetles. Moderately
resistant. It is extremely resistant to preservative
treatment.

Working Qualities. — The timber works fairly
easily with both hand and machine tools. Most of

the working qualities of K. grandifolia also apply
to this timber.

Uses. — It is very useful for furniture and interior
decoration, and forms a good quality joinery wood
suitable for ships’ cabins and railway coaches. It is
also used for boat planking and for the manufacture
of veneer and plywood.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: solitary but with a few
radial multiples of 2 or 3 small pores; circular
in outline, rarely angular; average pore diameter
lOOpm, range SOpm- 130pm; average vessel element
length 511pm, range 388pm-588pm; perforation
plates exclusively simple; vessel element end wall
inclination almost transverse; intervascular pitting
alternate. Imperforate tracheary elements: septate
fibers; average length 1448pm, range 1250pm-
1650pm. Fibers with simple pits on tangential walls.
Vascular rays: heterogeneous, mainly multiseriate,
generally 5 cells wide, 5 to 18 cells high.

NUMBER 14

PLATE 15

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 16

MELIACEAE

Lovoa trichilioides Harms

(Syn. L. klaineana Pierre)

Standard trade name; African walnut

Local names: Apopo, Sida (Nigeria), Dibetou, Noyer d’Afriqiie, Noyer de Gabon (France, French-speaking West Africa),

Akwantanuro, Dubinibiri, Pepedom (Ghana)

A large, evergreen tree with a heavy crown up to
150 ft high, attaining a girth of up to 12 ft. The
bole is 60-90 ft. The buttresses are rather short
and blunt. Leaves are pinnate with 6 pairs of sub-
opposite and elliptic leaflets, 3.5-8 in long. Flowers
are greenish white or white, numerous and small,
in large, lax panicles.

General Description. — The golden-brown heart-
wood, often with dark streaks, sometimes contains
“snakeholes” of I/2 in diameter and several inches
long, probably due to insect attacks. The sapwood,
which is distinguishable from the heartwood, is buff
or light brown in color. In most other respects the
wood resembles African mahogany. It is medium
hard and of medium weight, the average weight
being about 34 Ib/ft ^ seasoned, and about 49 Ib/ft
green.

Seasoning. — African walnut seasons fairly rapidly
without much degrade. The British Forest Products
Laboratory kiln schedule E is recommended (fprl,
1956).

Durability. — Moderately durable. It is extremely
resistant to preservative treatment. Sapwood is
moderately resistant.

Working Qualities. — The timber works satis-
factorily with hand and machine tools. Interlocked
grain material, especially quarter-sawn, has a ten-

dency to pick-up in machine operations. To avoid
pick-up, a cutting angle of about 15° should be
used. It takes nails and screws, stains and polishes
satisfactorily.

Uses. — It is used for furniture, joinery, cabinet
work, paneling, veneers, gunstocks, inlay-work, and
flooring.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: mixed multiples of 2 to 6 and
solitary small pores; circular in outline, rarely angu-
lar; average pore diameter 62p.m, range 13j.im-94[xm;
average vessel element length 444pm, range 200pm-
725pm; vessel wall thickness 3pm-4pm; perforation
plates exclusively simple; vessel element end wall
inclination oblique to transverse; intervascular pit-
ting alternate, rather large. Imperforate tracheary
elements: pitted fiber tracheids, average length
1914pm, range 1375pm-2438pm; fibers have no or
extremely minute pores on tangential walls. Vas-
cular rays: heterogeneous, mainly multiseriate, gen-
erally 3 cells wide, 15 to 38 cells high, but biseriate
and uniseriate cells also present; fusiform rays up
to 4 cells wide containing intercellular canals. Axial
parenchyma: paratrachial and apotrachial, abun-
dant, cells void of amorphous material. Crystals:
no crystals were found in tissues.

NUMBER 14

SMITHSONIAN CONTRIBUTIONS TO BOTANY i

PLATE 17

MELIACEAE

Turraeanthus africanus Hutchinson & Dalziel

Standard trade name: Avodire
Local name: Apapaye

A medium size tree 2-2.5 ft in diameter, branch-
ing low with a spreading crown. Leaves are pinnate
with long-acuminate or elongate-oblong leaflets,
rounded or shortly cuneate at the base. Flowers are
small, dull yellow, and densely pubescent. The tim-
ber is used for building. The bark and leaves are
used as fish poison.

General Description. — There is no distinction
between sapwood and heartwood. The pale cream
wood has a natural luster and darkens to a golden
yellow. The grain is often wavy or interlocked but
is sometimes straight. The figured material is more
distinctive and very attractive. The average weight
is about 34 Ib/ft ^ seasoned.

Seasoning. — Avodire can be seasoned fairly rap-
idly but tends to cup and twist. British Forest Prod-
ucts Laboratory kiln schedule E is recommended
(fprl, 1956).

Durability. — The timber is not durable. It is
extremely resistant to preservative treatment,
although the sapwood is permeable.

Working Qualities. — Avodire works fairly easily
with hand and machine tools and has a very small
dulling effect on their cutting edges. It produces a
smooth finish, polishes and glues well.

Uses.— Being a superior joinery timber, it is used
for interior and cabinet work. It is also used for
decorative veneer.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: solitary or in multiples of
2 or 3 pores; circular in outline, rarely angular;
average pore diameter 70pm, range 50pm-110pm; !
average vessel length 625pm, range 413pm-838pm; '
vessel wall thickness 3pm-4pm; perforation plates i
simple; vessel element end wall inclination slightly
oblique; intervascular pitting alternate, rather
small. Imperforate tracheary elements: nonseptate j
fiber tracheids; average length 1435pm; range
1 lOOpm-1 713pm; fibers with few simple pits on
tangential walls. Vascular rays: homogeneous, gener- :
ally biseriate, 3 to 17 cells high, but uniseriate and
multiseriate cells also present. Axial parenchyma:
apotracheal, cells without dark amorphous deposits.

NUMBER 11

PLATE 17

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 18

MORACEAE
Antiaris africana Engler

Standard trade name: Antiaris

Local names: Oro orgiovu (Nigeria) , Kyenkyen (pronounced Chenchen — Ghana)

A large, deciduous tree of the drier types of for-
est, to 130 ft high; with gray bark, the slash exuding
a watery latex which soon darkens to the color of
milky tea; ripe fruits red or orange. Plants in the
family Moraceae are recognized by the milky juice,
the prominent stipules which leave a scar on falling,
and the minute, unisexual flowers often arranged
on variously shaped receptacles.

General Description. — The wood is light and
medium soft with a recorded air-dry weight varying
from 23 to 33 Ib/ft the average being 27 Ib/ft
Green weight is about 42 Ib/ft The general
appearance of the timber is similar to obeche
(Triplochiton scleroxylon)] it is light yellow-brown
in color with no clear distinction between sapwood
and heartwood. The texture is medium to coarse,
and the grain interlocked.

Seasoning. — Antiaris seasons fairly rapidly, but
with a tendency to distort. British Forest Products
Laboratory kiln schedule A is recommended (fprl,
1956).

Durability. — It is a perishable wood. Logs are
susceptible to damage by ambrosia and longhorn
beetles. Sapwood of lumber is also susceptible to
pow’der-post beetles. It is permeable to preservatives.

Working Qualities. — Antiaris has similar work-
ing properties of obeche (Triplochiton scleroxylon).

It finishes cleanly in most operations if sharp cutters
are used. It nails and glues well, stains and polishes
satisfactorily.

Uses. — Used locally in Ghana for cutlass handles
and boxes, doors, benches, and canoes. It has been
used for plywood core. Suitable for furniture, in-
teriors, and also for light joinery. Antiaris has a
thick inner bark, which yields a strong and durable
cloth, providing satisfactory wrapping material for
baled rubber and other products.

Xylem Anatomy. — Growth rings present. Wood
diffuse-porous. Vessels: solitary but with a few
radial multiples of 2 to 4 pores; circular in outline;
average diameter IGSpm, range 125|.im-200|.im; aver-
age vessel element length 453|.im, range 350(,i,m-
650|.im; vessel wall thickness averages 3.75pm;
perforation plates scalariform (? ) ; vessel element
end wall inclination very slightly oblique to trans-
verse; intervasctilar pitting alternate, large pits. Im-
perforate tracheary elements: septate fiber tracheids;
average length 1260pm, range 1038pm-1500pm. Vas-
cular rays: heterogeneous, mainly multiseriate, gen-
erally 3 or 4 cells wide, varying considerably in
height, 6 to 35 cells; biseriate and uniseriate rays
also present: fusiform rays with numerous circular
pits. Axial parenchyma: paratracheal, vasicentric,
occasionally aliform, moderately abundant.

NUMBER 14

PLATE 18

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 19

MORACEAE

Chlorophora excelsa (Welwitsch) Bentham & J.D. Hooker

Standard tiade name: Iroko

Local names: Odum (Ghana) , Iroko (Nigeria) , Kambala (French-speaking West Africa)

A large tree of deciduous and evergreen forests
reaching 160 ft and up to 30 ft in girth. Unbut-
tressed and unbranched for 80 ft. The bark is
smooth but becomes brown and scaly. The leaves
of young trees of both sexes are 9X4 in, acuminate
and serrulate; on the mature tree they are entire.
4'he trees are dioecious; lemale llowers are on com-
pact spikes 2 in long, male llowers are in dense
spikes reaching 8 in long.

General Descripi ion. — Sapwood, pale in color,
is clearly distinguishable from the pale yellowish
brown or dark chocolate-brown heartwood. It is
a medium weight, averaging about 10 Ib/ft ‘
seasoned and about 65 Ib/ft ^ green. The grain is
typically interlocked. I’he texture is coarse.

Seasoning. — Iroko seasons w'ell without much de-
grade. The British Forest Products Laboratory kiln
schedule E has proved satisfactory (fprl, 1956).

Durabiltia'. — Very durable. The timber is resist-
ant to, but not immune from, termite attack. It is
extremely resistant to preservative treatment. The
sajrwood is permeable.

Working Qualities. — Iroko is hard to work with
hand and machine tools, and dulls ctitting edges
very rapidly. Due to its interlocked grain, care must
be taken in planing cjuarter-sawn material to avoid
pick-up; a reduction of cutting angle to about 15^
may be necessary. It takes nails and screws well,
stains and polishes well, although it recpiires grain
filler. It glues satisfactorily.

Uses. — It is extensively used locally for all kinds
of construction work and carpentry. It is used for
railroad cross-ties, bridges, fencing, carriage and

wagon construction, and for bearers and llooring.
Iroko is also used for tight cooperage and also for
containers for radioactive materials.

XvLEM Anatomy. — Growth rings present. Wood
diffuse-porous. Vessels; solitary or in pairs, rarely
3’s; circular to oval in cross-section; average pore
diameter 260[.im, range 100[im-390um; average ves-
sel element length ISOpm, range 250[im-625nm;
vessel wall thickness 4|.un-6j.un; jierforation plates
probably simple; vessel element end wall inclination
is transverse; intervascular pitting transitional, be-
tween alternate and opposite, slitlike and small.
Imperforate tracheary elements; nonseptate fiber
tracheids, average length ITSOpm, range 1563pm-
2275pm; simple pits few on the radial walls. Vas-
cular rays; heterocellular (upright and procumbent
cells — the upright cells confined to the top and bot-
tom of the ray), multiseriate, mostly 3 or 1 cells
wide, 10 to 25 cells high, biseriate rays rare, tini-
.seriate absent. Rays almost storied (transitional).
Axial parenchyma; paratracheal, aliform conllucnt.
Grystals; none observed, although generally noted
for its profuse crystals of calcitim oxalate, which
sometimes coagulate to form big lumps. Special
note; Tyloses present in vessels.

Using Tippo’s 1916 concept of phylogeny, with
special reference to xylem anatomy, this wood ap-
pears to be generally more advanced due to the
simple transverse perforation plate, shorter circular
vessels, transitional pitting of vessel w'all between
opposite and alternate types, paratracheal axial
parenchyma and the almost storied nature of the
rays and fibers.

NUMBER 14

PLATE 19

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 20

MORACEAE

Musanga cecropioides R. Brown
(Syn. M. sniithii R. Brown)

Local name; Odwuma (Ghana), also known as umbrella tree or corkwood

A small- to medium-sized, erect tree up to about
90 it high. Girth over 6 It above roots. Common on
old farms in closed forest. Natural regeneration is
prolihc, often gregarious. Odwuma is of rapid
growth and has stilt or prop roots. Branches are
spreading, the crown umbrella-like. Buds are en-
closed in large, red, hairy, and deciduous stipular
sheaths up to 8 in long. Leaves are alternate, 18 X
4 in, grayish and hairy below, deeply digitately
lobed, acuminate at tip, with the base cuneate.
Petiole up to about 24 in long, browm, tomentose,
with numerous lateral nerves. Flowers inconspicu-
ous. Fruits succulent, green.

General Description. — The timber is very light.
There is no distinction between sapwood and
heartwood, the color being pinkish white through-
out. Information on seasoning and other qualities
is lacking. It is perishable.

Uses. — It is used instead of cork to serve as rafts
or floats. It is used for temporary walls, isothermic
ceilings, and inferior roofing shingles. Charcoal

made from this tree is used as a floor polish (Irvine,
1961). Musanga species have very long fibers with
thin walls and are, therefore, considered suitable
for papermaking.

Xylem Anatomy. — Growth rings are absent.
This wood is diffuse-porous. Vessels are usually
solitary, occasionally in pairs, circular in outline.
Average pore diameter 28pm, range 9pm-34pm;
vessel wall thickness averages 4pm; average vessel
element length 535pm, range 388pm-688pm. Fiber
tracheids, average length 535pm, range 350pm-
1225pm. The wood is storied. Pits of tracheids are
very tiny and without pattern of distribution. Per-
foration plates of vessels are simple and transverse.
Pits on vessel walls are bordered and arranged both
oppositely and alternately. Vascular rays are heter-
ogeneous, mainly multiseriate, although some are
uniseriate. Rays are 250pm-850pm tall and 15pm-
50pm wide. Axial parenchyma is scanty and anatra-
cheid-vasicentric. Crystals are rhomboidal and
found in rays.

NUMBER 14

PLATE 20

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 21

OCHNACEAE

Lophira alata Banks ex C. F. Gaertner

Standard trade name: Ekki

Local names: Kaku (Ghana), Eba (Nigeria), Azobe (France and French-speaking West Africa)

Ekki may reach a height of 160 ft to 180 ft and
a diameter of more than 6 ft at breast height. The
bole has no buttresses but the basal swelling
may extend for some 12 ft up the trunk. The bole
is often free of branches for 80 to 100 ft. Crown
triangular, bark reddish brown, peeling in loose
Hakes, slash red, leaves shorter, broader, and more
obovate than those of savanna form (Irvine, 1961 ),
petioles also shorter. Flowers white or golden yel-
low. Fruits over one inch long, pointed, nearly
1/2 in wide, broader than those of L. lanceolata,
wing also much shorter, about 1/0 in long (Irvine,
1961:91).

General Description. — Ekki is outstanding for
its hardness and weight, weighing from 56 to 71
Ib/ft ^ at 12% Mc. The green weight is about 77
Ib/ft at 45% MC. The specific gravity ranges from
0.74 to 0.97 based on volume when green and oven-
dry weight. Heartwood is red or deep chocolate
brown with a mottled appearance clue to conspic-
uous white deposits in the pores. The sap wood is
paler in color and about 2 in in width. The grain
is usually interlocked; the texture coarse and un-
even.

Seasoning. — It is an extremely refractory species.
Not only does it dry very slowly, but severe split-
ting and some distortion are likely to occur during
seasoning. It needs to be stacked with special care.
British Forest Products Laboratory kiln schedule
B is recommended for this species (fprl, 1956).

DtRABiLiTY. — Damage by ambrosia (pinhole
borer) beetles is occasionally present. It is resistant
to, though not immune from, attack by termites.
Ekki is rated the most durable timber on the west
coast of Africa. Maritime structures in France,
Belgium, and Holland have remained intact after
more than 20 years of service. Piers were found in

excellent condition after 12 years of standing in
brackish water infested with teredos (Forest Prod-
ucts Laboratory, 1965). In temperate climates the
wood is almost rot-proof. It is extremely resistant
to preservative treatment.

Working Qualities. — The timber is difficult to
work with hand and machine tools. Dry material
blunts cutting edges fairly quickly but the blunt-
ing effect of green material is not so severe. Some
tearing occurs in planing with the normal cutting
angle of 30°, but the finish is usually satisfactory.
The timber tends to char in boring. It cannot be
nailed without preboring. It has variable but gen-
erally good gluing properties.

Uses. — The high durability and hardness of ekki
make it particularly suitable for pilings. It is re-
garded as superior to reinforced concrete for all
hydraulic works or structures, such as landing
stages, piling, wharves, dams, or locks. In Africa
it is used untreated for sleepers and for construc-
tion work, such as bridges. It is a good heavy-duty
flooring timber for warehouses and factories where
a very smooth surface is not essential.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: mostly solitary, others in
multiples of 2 or 3, oval; average pore diameter
196pm, range 98pm-244pm; average vessel length
308pm, range 210pm-560pm; vessel wall thickness
4pm; perforation plates simple; vessel element end
wall inclination slightly oblique to transverse; in-
tervascular pitting alternate. Imperforate tracheary
elements: average length 1250pm, range 1150pm-
2300pm. Vascular rays: homogeneous mostly multi-
seriate, 2 to 4 cells wide, 8 to 26 cells high; uni-
seriate and biseriate also present but few. Axial
parenchyma: paratracheal, tendency towards ali-
form. Tanniferous material present in some vessels.

NUMBER 14

PLATE 21

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 22

RUBIACEAE (NAUCLEACEAE)

Mitragyna stipulosa (DeCandolle) O. Kuntze

Standard trade name: Abura
Local name: Subaha

A swamp forest tree up to 100 ft tall, sometimes
of vast size; leaves simple, opposite with interpeti-
olar stipules: flowers small, scented; sapwood white,
heartwood pinkish yellow, moderately hard and
straight-grained.

General Description. — It is a light-weight wood,
average weight being about 35 Ib/ft ^ seasoned. Its
green weight averages about 55 Ib/ft The color
of the wood is light yellowish brown or pinkish
brown. It has moderately straight or interlocked
grain and even texture.

Seasoning. — Abura seasons rapidly and well with-
out any degrade. British Forest Products Labora-
tory kiln schedule K is strongly recommended
(fprl, 1956).

Durability. — It is not durable. It is moderately
resistant to preservative treatment; the sapwood,
however, is permeable.

Working Qualities. — This timber usually works
well with hand and machine tools bnt has a vari-
able dulling effect on cutting edges. For a good
finish, then, sharp cutting edges should be em-
ployed. It stains and polishes well and takes light
nails satisfactorily.

Uses. — Abura is used for light construction work.
Since it is acid resistant, it is used for battery boxes

as well as laboratory fittings, brick backs, and some
classes of pattern making.

Xylem Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels: mostly paired but also soli-
tary and in radially oriented (occasionally tangen-
tial) groups of 3 to 5; mostly oval pore openings
but sometimes circular or somewhat angular; aver-
age radial pore diameter 60pm, range 40pm-
70pm; average tangential pore diameter 80pm,
range 55pm- 105pm; average vessel element length
608pm, range 275pm-913pm; vessel wall thick-
ness 3pm; perforation plates not seen; vessel
element end wall inclination 15° to 45° from
horizontal: intervascular pitting alternate. Im-
perforate tracheary elements: nonseptate fiber

tracheids, average length 1701pm, range 963pm-
2313pm; fiber tracheids with slitlike pits on radial
and tangential walls, slits slightly inclined from
the horizontal. Vascular rays: heterogeneous; largely
multiseriate, only a few uniseriate rays seen; mostly
2 (sometimes 3) cells wide, 9 to 49 cells high ex-
cluding uniseriate and biseriate tails; tails 2 to 6
cells high, occasional multiseriate rays divided near
middle by uniseriate row of ray cells; ray cells in
part occluded with dark amorphous material. Axial
parenchyma: apotracheal, diffuse, isolated or in
small groups of radially oriented cells.

NUMBER 14

PLATE 22

SMIIHSOXIAN CONTRIBUTIONS TO BOTANY

PLATE 23

RUBIACEAE (NAUCLEACEAE)

Naitclea diderichii (DeWildeman & Durand) Merrill

Standard trade name: Opepe

Local names: Jusia (Ghana and Ivory Coast) , Bilinga (Cameroons)

Large trees abundant in wet places in evergreen
and deciduous forests in Liberia, Ivory Coast,
Ghana, South Nigeria, British Cameroons, Vbdngi-
Shari, Gabon, Congo, Uganda, and Mozambique,
riie unbuttressed trunks attain a height of 120
ft and a girth of 9 ft, with yellowish rough bark
having loose, papery scales; slash exudes a yellowish
to Irrown sap that becomes sticky. Twigs are black,
speckled.

The large (9-12 X 5-7 in), shining leaves are
elliptic, acute at the ends, keeled towards the base,
and stipulate. They are mostly deciduous except
at the ends of shoots, and the nodes are often oc-
cupied Iry ants (Kennedy, 1936:216).

The small, white flowers are hairy inside and
appear from February to June in small, globose,
terminal heads. The fruit is yellow, fleshy, in a
globose head deeply pitted between the deeply
fused calyx lobes. The fruit dries hard, with em-
l:)edded seeds, and is eaten in times of scarcity.

General Description. — The sapwood is white,
the heartwood golden yellow', darkening later. It
is hard, moderately heavy, average weight being
about -16 Ib/ft seasoned, and about 70 Ib/ft^
when green. The grain is usually interlocked or
irregular. The texture is fairly open, owing to
rather large pores.

Seasoning. — With quarter-sawn material, season-
ing appears to be fairly quick with little degrade,
but llat-sawn timber is apt to prove refractory
(eprl, 1956). British Forest Products Laboratory
kiln schedule E is recommended.

DtiRABiLiTv. — Opepe is very durable. It is mod-
erately resistant to preservative treatment. The
sapwood is, however, permeable.

Working Qualities. — The wood works well, has

a lustrous surface, and takes a good polish; it has
a tendency to split when nailed but takes screws
fairly well. The timber can be glued satisfactorily.

Uses. — It is eminently suitable for harbor work
such as piles, fenders, and wallings because of its
resistance to marine borers. It is used for heavy
structural work, planking, railway wagon bottoms,
railway cross-ties, and also as telegraph cross-arms.
Opepe is also used for fufu mortars (in Ghana),
canoes, and for making charcoal. In French Equa-
torial Africa the boiled, steeped bark is used to
treat gonorrhea and stomach complaints. Leaves
are used for fevers and diarrhea. Workers with the
wood have suffered, sometimes fatally, from a wood
alkaloid said to be a cumulative cardiac poison
(Henry, 1949:665).

Xylem Anatomy. — No annual rings. Wood dif-
fuse-porous. Vessels solitary, oval, none angular;
average pore diameter lOOpm, range 150pm-210(.im;
average vessel element length 711pm, range 375pm-
1000pm; vessel wall thickness ca. 6.25pm; perfora-
tion plates mostly inclined about 10° to 20°, some
transverse, simple perforations; intervascular pits
very small, bordeied with slitted apertures, alter-
nate. Imperforate tracheary elements: no septate
fibers evident; many fibers with few or no pits,
others with numerous bordered pits in a single
rank. Vascular rays: mostly heterogeneous and
heterocellular; 1 to 3 seriate cells, 3 to 37 cells
high; many with long “tails”; no fusiform rays.
Axial parenchyma: apotracheal, scanty, in short or
broken tangential chains.

Only in the lack of angular vessels and in the
simple, mostly transverse perforation plates does
this wood show advanced characters. In other re-
spects it is primitive.

NUMBER !4

PLATE 23

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 24

SAPOTACEAE

Tieghemella heckelii Pierre ex. A. Chevalier

(Syn. Mimusops heckelii Hutchison & Dalziel)
Standard trade name: Makore
Local name: Baku (Ghana)

A large evergreen and deciduous forest tree
growing up to 200 ft high and 30 ft in girth. The
leaves are dark green and shining with numerous
faint lateral nerves, obovate, and measure 6 X 2.5
in. The llowers are white, glabrous outside, axillary
with pedicels 0.75 in long, and are crowded at tips
of branchlets.

General Description. — Makore is moderately
hard and of medium weight, seasoned weight aver-
aging about 39 Ib/ft^ and green weight about 53
Ib/ft 3. The 2-3-in wide sapw'ood is lighter in color.
The heartwood varies in color from pinkish brown
to reddish brown or dark blood-red. The gen-
erally interlocked grain is sometimes straight. The
luster is high, texture uniform and fine.

Seasoning. — Makore has a moderate rate of sea-
soning often with little degrade. British Poorest Prod-
ucts Laboratory kiln schedule H is recommended
(fprl, 1956).

Durability. — Makore is one of the most durable
timbers of West Africa. It is very resistant, though
occasionally attacked by pinhole borers and powder-
post beetles. In preservative treatment it is
extremely resistant, the sapwood being moderately
resistant.

Working Qualities. — The timber works readily
with machine and hand tools; it does, however.

cause rapid blunting of cutting edges. A good finish
is usually obtained with standard machining con-
ditions. It stains and polishes well, giving excellent
results. Nailing tends to split it. It glues satis-
factorily.

Uses. — It compares favorably with African ma-
hogany and can therefore be used for all purposes
which African mahogany is used. It is used for
furniture and fine decorative work, for veneer and
plywood.

Xylem Anatomy. — Growth rings absent. Wood
diffuse porous. Vessels: generally in radial multi-
ples of 3 to 6 pores but solitary pores and vertical
pairs present; oval in outline; average pore diam-
eter 66pm, range 40pm-85[j,m; average vessel ele-
ment length 585pm, range 388pm-900pm; vessel
wall thickness 3.5pm; perforation plates simple;
vessel element end wall inclination slightly oblique
to strongly oblique; intervascular pitting alternate,
relatively large. Imperforate tracheary elements:
nonsepta te fibers, average length 1268pm; range
1000pm-1650pm; fibers with a few scattered simple
pits on tangential walls. Vascular rays: heterogene-
ous, mainly multiseriate, generally 3 cells wide, 8
to 18 cells high, but biseriate cells also present.
Axial parenchyma: apotracheal, banded, cells with
gummy deposits within. Crystals absent.

NUMBER 14

PLATE 24

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 25

STERCULIACEAE

N esogordonia papaverifera (A. Chevalier) R. Capuron

Standaid trade name: Danta
Local name: Danta (Ghana)

A deciduous forest tree up to 110 ft in height
;md 0 ft in diameter. Leaves alternate, up to 5 X
2.25 in, ovate-elliptic, apex at nminate, base enneate,
margins entire, minutely stellate-pnbernlons below,
becoming glabrous, d’he llowers are yellowish white,
lew, about 0.5 in long ami in slender, axillary cymes.

Gint-ral DI'SCRItiion. — Danta has an average
tveight of 16 Ib/ft •* seasoned anti about 63 Ib/ft
green. It has a fine, even texture. The retltlish
brown heartwood is distint t from the light-colored
sapwood, which is nsnally about 2 in or more wide.
Danta has a narrowly interhidcing grain prothicing,
when t]tiarter-sawn, a stripetl appearance somewhat
similar to that of sajtele.

Si ASONiNG. — Danta seasons rather slowly, but
well, with comparatic ely little tlegrade. Knots have
the tentlency tt) sjilit. Biitish Forest Protlncts Lab-
oratory kiln sthetlnlc E is recommended (fprl,
1956).

Durabiitit'. — It is mtiderately durable. The
heartwood is resistant to preservative treatment,
whereas the sapwood is moderately resistant.

Working Qualtitfs. — I’he timber works fairly
easily with both hand and machine tools. The
grain has a tendency to pick-up, especially when
the cpiarter-sawn material is planed. This can be
eliminated with the redtiction of the ctitting angle

to about 15°. It tends to split on nailing but glties
and finishes satisfactorily.

Uses. — Danta is suitable for veneer and plywood,
tised for carriage and wagon work, and for general
construction. It is also used for telephone poles and
cross-arms and for tool handles. Because of its
smooth wear and high resistance to abrasion, it is
recommended for most forms of flooring, jrarticn-
larly where a decorative effect is desirable.

Xvi.EM Anatomy. — Growth rings absent. Wood
diffuse-porous. Vessels; solitary or in chains of 2
to d; circular to wide elliptic in outline, occasion-
ally angular, tyloses present; average pore diameter
75pm, rather uniform; average vessel element length
326pm, range 275pm— 113pm; vessel wall thickness
about 3pm; perforation plates generally simple;
vessel element end wall inclination transverse to
slightly oblitpie, intervascular pitting alternate,
average in size. Nonseptate fibers with scanty, simple
pitting scattered on radial W’alls. Vascular rays:
storied, homogeneous, homocellular, mostly biseri-
ate, occasionally multiseriate, 15 to 25 cells high.
Axial parenchyma: paratracheal, abundant, with
stained deposits in most; in uniseriate, tangential
bands. The w'ood is a relatively advanced one.
Special note: axial parenchyma in uniseriate,

tangential chains.

NUMBER 14

PLATE 25

PLATE 26
STERCULIACEAE
Tarrietia utilis Sprague

SMITHSONIAN CONTRIBUTIONS TO BOTANY

Standard trade name: Niangon
Local name: Nyankom (Ghana)

A tree with a height of over 100 ft and a girth
of up to 9 ft; bole cylindrical, up to 60 ft, with
arched buttress and stilt roots. Leaves brown and
densely scaly below, quite variable in shape, simple
and entire on fertile branches and seedlings, digitate
with 5 to 7 leaflets otherwise. Flowers are small,
white, in racemes, axillary clusters.

General Description. — The heartwood is rather
variable from pale pink to reddish brown and is
not clearly demarcated from the grayish sapwood.
The timber is medium hard and has wide range
in weight from about 32 to 45 Ib/ft-’’; the average
weight about 39 Ib/ft Niangon resembles African
mahogany superficially, but its greasy feel and con-
spicuous rays readily distinguish it from African
mahogany.

Seasoning. — Seasons rapidly and well, with little
or no distortions. British Forest Products Labora-
tory kiln schedule E is recommended (fprl, 1956).

Durability. — It is moderately durable and ex-
tremely resistant to preservative treatment.

Working Qualities. — Niangon works easily and
readily with machine and hand tools. Its dulling
effect on cutting edges is very little. The wood cuts
and bores cleanly; it nails, screws, glues, polishes
and stains satisfactorily, though a grain filler may

be required during polishing.

Uses. — Suitable for furniture, building, both in-
terior and exterior, joinery, and cabinet work. It
is also used for boat building.

Xylem Anatony. — Growth rings absent. Wood
diffuse-porous. Vessels: solitary with a few multiples
of 2 or 3 pores (rarely more), or occasionally a
close association of 2 or 3 full-sized vessels; circular
to ellipsoidal in shape; average pore diameter
242pm, range 160pm-310pm; average vessel ele-
ment length 382pm, range 325pm-450pm. Vessel
wall thickness ca. 10pm-12pm; perforation plates
appear scalariform (but this is not clear), vessel
end wall inclination very slightly oblique to trans-
verse; intervascular pits numerous and alternate,
generally small. Imperforate tracheary elements:
average length 1903pm, range 1375pm-2375pm;
walls with scattered pits. Vascular rays: mainly
homogeneous and uniseriate, at times biseriate,
and then a tendency towards heterogeneity; fusi-
form rays up to 10 cells wide and 50 cells high,
frequently with dark deposits. Axial parenchyma:
apotracheal, diffuse and plentiful, cells with dark
deposits.

Appears somewhat primitive in xylem anatomy
when applying Tippo’s principles.

NUMBER 14

PLATE 26

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 27

STERCULIACEAE

Triplochiton scleroxylon K. M. Schumann

Standard trade name: Obcchc, African whitewood
Local name: Wawa (Ghana)

A large tree up to 160 ft high and 10 ft or more
ill girth, bole straight and nnbranched, up to 80
ft. Extensive, sharp buttresses extend as far as 25
ft up. The leaves are eaten by the African silk-
worm, Anaphe venata.

General Description. — Obeche, soft and light,
has an average weight of about 24 Ib/ft ^ when
seasoned and about 35 Ib/ft green. Its color is
nearly white or pale straw. There is no clear dis-
tinction between sapwood and heartwood, the sap-
wood being about 3-4 in wide. The grain is typi-
cally interlocked and the texture moderately coarse.

Seasoning. — Obeche seasons very rapidly and
well, with very little or no defects. British Forest
Products Laboratory kiln schedule L is recom-
mended (fprl, 1956).

Durability. — The timber is susceptible to attack
by ambrosia and powder-post beetles. It is not dur-
able. In preservative treatment the sapwood is
permeable but the heartwood is resistant.

Working Qualities. — The wood works very
easily with all hand and machine tools with little
dulling effect on the cutting edges. The timber
finishes well in most operations, taking nails and
screws readily, although they do not hold well

under certain circumstances. It requires grain filler
in polishing.

Uses. — Used for interior core of plywood, for
crating and packing cases. It is also used for in-
teriors of drawers and cupboards.

Xylem Anatomy. — Slight evidence of growth
rings. Wood diffuse-porous, but looks slightly ring-
porous in distribution. Vessels: solitary but with
a few radial multiples of 2 or 3 pores; circular in
outline, slightly angular, average pore diameter
126pm, range 110pm-150pm; average vessel ele-
ment length 300pm, range 212pm-375pm; perfo-
ration plates exclusively simple; vessel element end
wall inclination slightly oblique to transverse; in-
tervascular pitting opposite, rather large. Imper-
forate tracheary elements; septate fiber tracheids,
average length 1690pm, range 1225pm-2075pm;
fibers with few simple pits on tangential walls.
Vascular rays; heterogeneous, mainly multiseriate,
generally 7 cells wide, 34 cells high, but biseriate
and uniseriate cells also present; fusiform rays up
to 4 cells wide. Axial parenchyma: apotracheal,
abundant. Biseriate and uniseriate also present;
fusiform rays up to 5 cells wide.

NUMBER 14

PLATE 27

SMITHSONIAN CONTRIBUTIONS TO BOTANY

PLATE 28

ULMACEAE

Celtis mildbraedii Engler

(Syn. C. soyansii Engler)
Standard trade name: Celtis
Local name: Esa-fufuo

A common mixed deciduous forest tree growing
up to 120 ft high and up to 10 ft in girth. The
leaves are up to 7 X 3 in long, acuminate, elliptic
obovate, stipulate, coarsely toothed, especially to-
wards the apex, rarely entire. The flowers are
minute, axillary, greenish white, rusty pubescent.

General Descriptions. — The wood weighs 45-50
Ib/ft 3 seasoned and averages about 49 Ib/ft^; it
is hard and medium heavy. High luster, fine tex-
ture and interlocked grain, although sometimes
straight. Celtis species have whitish or light yellow
color when green, becoming grayish white later.

Seasoning. — Celtis can be kiln seasoned fairly
rapidly from the green condition with little de-
grade.

Durability. — Celtis is not durable. It is sus-
ceptible to severe damage by ambrosia and powder-
post beetles. In preservative treatment the sapwood
is said to be permeable while the heartwood is mod-
erately resistant.

Working Qualities. — With machine tools celtis
works well, but it is hard to work with hand tools
as it dulls the cutting edges moderately. It finishes
well without requiring special treatment. It peels
satisfactorily and glues well, but nailing may split
it. Preboring may be necessary.

Uses. — Celtis can be used for flooring and tele-
graph poles (treated). It is used for house posts,
sports gear, and also locally (in Ghana) for fnfii
pestles. It has good strength properties and should
be a useful substitute for ash. It is a good substi-
tute for maple for dance floors (fprl, 1956). It is
used for furniture framing, commercial plywood,
and light colored veneer.

Xylem Anatomy. — Growth rings variable (?).
Wood diffuse-porous. Vessels: in 2’s aird 3’s, but
range from 1 to 7; generally circular; average pore
diameter 59pm, range 50pin-70pm; average vessel
element length 399pm, range 288pm-538pm; vessel
wall thickness undetermined; perforation plates
simple; vessel element end waif inclination oblique
to transverse; intervascular pitting alternate. Im-
perforate tracheary elements; nonseptate fiber tra-
cheids, average length 1346pm, range 1063pm-
1563pm; fibers with no pits. Vascular rays: homo-
geneous, multiseriate (triseriate), generally 3 cells
wide, 6 to 25 cells high, but uniseriate and biseriate
present; no fusiform rays; no intercellular canals.
Axial parenchyma: paratracheal, scanty with no
amorphous deposits, apotracheal, abundant. Crys-
tals: not present.

NUMBER 14

PLATE 28

References

Cliflord, N.

1953. Commercial Hardwoods. London: Isaac Pitman and
Sons.

Committee on Nomenclature of the International Association

of Wood Anatomists

1957. International Glossary of Terms Used in Wood
Anatomy. Tropical H’ood.s, 107:1-36.

C6tc, Jr., W. A.

1965. Cellular Ultrastructure of ll'oody Plants. Syracuse:
Syracuse University Press.

Dadswell, H. E., and A. B. Wardrop

1955. TIte Structure and Properties of Tension Wood.
Holzforchung, 9:97-104. (.Also C.S.I.R.O. Australia
Division of Forest Products Reprint No. 269.)

Dalziel, J. M.

1937. The Useful Plants of Il'cst Tropical Africa. London:
Crown Agents for the Colonies.

Eggcling, W'. J,, and C. M. Harris

19,39. Fifteen Llganda Timbers. Number IV^ in L. Chalk,
J. Butt Davy and A. C. Hoyle, editors, Forest Trees
and Timbers of the British Empire. Oxford: Claren-
don Press.

Esau, K.

1960. Anatomy of Seed Plants. New York: John Wiley
and Sons.

Forest Products Laboratory

1965. The H oods of Liberia. FVashington: United States
Department of Agriculture Forest Service.

Forest Products Research Laboratory (fprl)

1956. A Handbook of Hardwoods. London: Her Majesty’s
Stationery Office, Department of Scientific and In-
dustrial Research.

Henderson, F. Y.

1939. Timber, Its Properties, Pests and Preservation. Lon-
don: Crosby Lockwood & Son, Ltd.

Fleniy, Thomas Anderson

1949. The Plant Alkaloids. Philadelphia: Blakiston's.

Irvine, F. R.

1961. IVoody Plants of Ghana. London: Oxford ITiversity
Press.

Jay, B. A.

1947. Timber of ]\’est Africa. London: Timber Develop-
ment Association Ltd.

Johnston, D. D.

1970. Timber Drying: The Principles Involved. Journal
of the Institute of Wood Science, 26(5.2):3.

Kennedy, J. D.

1936. Forest Flora of Southern Nigeria. Lagos: Govern-
ment Printer.

Kribs, D. A.

1935. Salient Lines of Structural Specialization in the
Wood Rays of Dicotyledons. Botanical Gazetteer,
96:547-557.

1937. Salient Lines of Structural Specialization in the
Wood Parenchyma of Dicotyledons. Bulletin of the
Torrey Bcstanical Club, 64:177-186.

Metcalfe, C. R.. and L. Chalk

1950. Anatomy of the Dicotyledons. 2 volumes. Oxford:
Clarendon Press.

Panshin, A. J., and Carl De Zeeuw

1964. Textbook of IFood Technology. Volume 1, 2nd edi-
tion. New York: Mcgraw-Hill Book Company.

Pillow, M. Y., and R. F. Luxford

1937. Structure, Occurrence and Properties of Compres-
sion Wood. United States Department of Agriculture
Technical Bulletin, 546.

Tippo, O.

1941. A List of Diagnostic Characteristics for Descriptions
of Dicotyledonous Woods. Transactions of the Illi-
nois State Academy of Science, 34:105-106.

1946. The Role of Wood Anatomy in Phylogeny. Ameri-
can Midland Naturalist, 36:362-372.

Glossary

In this glossai'y are the principal terms used in
describing the anatomical features of timbers.
Although most of the terms apply to the secondary
xylem, there are many that are applicable to the
primary xylem as well. For the most part, this glos-
sary is based on the definitions of descriptive terms
by Kribs (1935, 1937), Tippo (1941), Metcalfe and
Chalk (1950), the Committee on Nomenclature of
the International Association of Wood Anatomists
(1957), and Esau (1960).

Axial parenchyma cells. Parenchyma ceils de-
rived from fusiform cambiai initials. Cells of the
same length as the parent fusiform cambiai initials
are designated fusiform parenchyma. When further
cell divisions take place, the original fusiform cell
divides to form an axial series of shorter cells; this
series of ceils is termed strand parenchyma, as in
Parkia (Leguminosae). Axial parenchyma are pres-
ent in most species, ranging from abundant to
sparse, and sometimes absent. Simple pits, some-
times bordered or half-bordered, occur between
xylem parenchyma cells.

Classification of axial parenchyma is ordinarily
based on the relationship of the parenchyma to
vessels in the same species. There are a number
of systems, each more or less complex.

Apotrackeal parenchyma: Axial parenchyma that
is typically independent of the vessels.

Banded apotrackeal axial parenchyma form con-
centric lines or bands typically independently of
the vessels. Bands may be one or more cells wide.

Diffuse: Single apotradieal parenchyma strands
or cells which are distributed irregularly among
fibers.

Diffiise-in-aggregates: Axial apotradieal paren-
chyma grouped in short tangential lines from ray to
ray. This type is often called reticulate parenchyma
w'hen regularly formed.

Marginal apotradieal parenchyma cells are
formed either singly or in a more or less continuous
layer of variable width at the edge of a growth
ring and may be either terminal (appearing at the
close of a growth period) or initial (appearing at

the beginning of a growth period).

Paratracheal parenchyma: Axial parenchyma

associated with the vessels or vascular tradieids.

Aliform paratracheal parenchyma have wing-like
lateral extensions.

Banded paratracheal axial parenchyma form con-
centric lines or bands that are associated with the
vessels.

Confluent parenchyma are coalesced aliform types
which form irregular tangential or diagonal bands.

Scanty paratracheal parenchyma are incomplete
sheaths or occasional parenchyma cells around the
vessels.

Crystals. Crystals are of very common occur-
rence and are sometimes valuable features in identi-
fication. Frequently crystals are found in axial
parenchyma and ray ceils, and less frequently in
septate fibers and in tyloses. In some genera there
are modifications of the crystal-containing cells,
which are sufficiently consistent and infrequent to
form useful guides to families and sometimes to
genera. These are (1) presence of crystals in en-
larged cells or idioblasts, (2) clianges in the cell
wail, causing the crystalliferous ceils to become
sclerosed, and (3) the presence of a iiimiber of
crystals of variable size and shape in one cell. There
are several types of crystals.

Aciciilar crystals are needle-shaped, often small,
free in the cells, and not filling them.

Crystal sand is a granular mass of very fine small
crystals.

Druse: Spherical crystal clusters either attached
to the ceil wall by a peg or lying free in the cells.

Elongated crystals are about four times as long
as broad with pointed or square ends.

Raphides: Bundles of long needle-shaped crystals,
tending to fill the whole cell.

Rhomboidal, square, or diamond-shaped crystals
are the most common of all types. They may occur
singly or as two or more per cell.

Rod-like crystals are similar to elongated crystals
in shape, but only about twice as long as broad,
and they usually have square ends.

SMITHSONIAN CONTRIBUTIONS TO BOTANY

Disjunctive parenchyma. Axial or radial pa-
renchyma cells partially disjoined during the proc-
ess of differentation; contact is maintained by means
of tubular processes.

Fibriform vessel elements or perforated fiber-
tracheids. Fiber-like vessel elements, fusiform in
shape and with bordered pits, usually with very
small, nonterminal perforation, which occur only
in short axial series and are completely dissociated
from the ordinary vessel elements in the same wood.
These peculiar cells are extremely rare in woody
plants and are seen in the vines of Passifloraceae.

Growth ring. Increments of growth that result
from the discontinuous action of the vascular cam-
bium. When present, they may be sharply defined
and distinct, or weakly defined and indistinct.

Imperforated tracheary elements consist of
tracheids and fibers.

Tracheids: Imperforate wood cells with bor-
dered pits to congeneric elements of the same
magnitude as those in vessels of the same wood.
Tracheids in hardwoods are short fibrous cells and
are as long as the vessel elements with which they
are associated. Vasicentric tracheids are short, irreg-
ularly formed tracheids with conspicuous bordered
pits, in the immediate proximity of vessel elements
that do not form part of a definite axial row. Vas-
cular tracheids are specialized cells in certain hard-
woods, similar in shape, size, and arrangement to
small vessel elements, but differing from them in
being imperforate at the ends. The lateral walls
of vascular tracheids are copiously pitted and
frequently possess spiral thickening as well.

Fibers. A term of convenience for elongated cells
with pointed ends and thick or not infrequently
thin walls. This term is used often to include
tracheids but it is limited here to fiber-tracheids
and libriform wood fibers. Fiber-tracheids is a
typically fibrous cell with a relatively thick wall,
tapering pointed ends, and small bordered pits.
Libriform wood fibers are elongated, commonly
thick-walled cells with simple pits; usually distinctly
longer than the cambial initial as inferred from the
length of the vessel elements and axial parenchyma
strands.

Fibers are classified by length as follows: ex-
tremely short (< 0.5 mm = BOOpin), short, very
short (0.5-0. 7 mm = 500pm-700|Lm), moderately

short (0.7-0. 9 mm = 700pm-900pm ), medium-
sized (0.9-1. 6 mm = 900pm-1600pm), moderately
long (1.6-2. 2 mm = 1600pm— 2200|.un ), long, very
long (2. 2-3.0 mm = 2200pm-3000pm), and ex-
tremely long (over 3.0 mm = over 3000pm).

Included (or intraxylary) phloem. Phloem
strands or layers that are included in, and sur-
rounded by, the secondary xylem in certain
dicotyledonous woods.

Intervascular pitting. Strictly speaking, inter-
vascular pitting refers to the pits in the walls of
adjacent vessel elements. The term is sometimes
applied to pitting between any tracheary cells
(prosenchyma) in wood. Pit-pairs between vessel
elements and other prosenchymatous cells are
usually bordered. Where they lead to parenchyma-
tous elements, pits may be bordered, simple or
half-bordered. Intervascular pits appear to best
advantage on the tangential faces of vessel elements.
Variation in the arrangement, size, and shape of
these pits forms a useful and important diagnostic
and descriptive feature. Pitting types are classified
according to average size, as follows: very small to
minute (up to 4pm), small (4pm-7pm), medium-
sized (7|.un-10j.un), large (10pm-15|Lm), or very
large (over 15pm). Pitting arrangements are as
follows:

Alternate: Multiseriate pitting in which the pits
are in diagonal rows. Pits are circular or oval if
they are uncrowcled; if crowded they are polygonal
and frequently hexagonal.

Opposite: Multiseriate pitting in which the pits
are in horizontal series, pits in each series being
directly above and below pits in adjacent series.
Crowding here may cause individual pits to be
rectangular.

Scalariform: Pitting in which elongated or linear
pits are arranged in a ladder-like series.

Transitional: Pitting intermediate between sca-
lariform and opposite, which possesses some of the
characteristics of each.

Perforation plate. That portion of the wall
involved in the coalescence of two vessel elements,
which bears the perforation through which the ves-
sel elements are interconnected. Perforation plates
show to the best advantage in radial sections that
are fairly thick, sometimes 25pm or more.

Ephedroid: The ephedroid perforation plates is

NUMBER 14

a special type found in Ephedvn, and is character-
ued by a small group of rather large circular
openings.

Multiple perforation: The perforated end wall in
a vessel element consisting of two or more openings.

Reticulate: A perforation plate with many open-
ings presenting a net-like appearance. This type of
plate is often produced by the more or less profuse
branching of the bars in a scalariform perforation
plate, and the two types often occur together in the
same wood. If the openings are small, circular, or
polygonal, the plate can be described as foraminate.

Scalariform: A plate bearing multiple perfora-
tions that are elongated and parallel. In the forma-
tion of scalariform plates, the remnants of the cell
wall that are left between the perforations are called
bars. The number and width of bars vary consider-
ably and are of diagnostic significance. They may
be classified according to average number of bars,
as follows: few (5 or less), intermediate (5 to 15),
or many (over 15); and by the width of perfora-
tions. The range and most frequent range should
be determined and reported.

Simple perforation: The perforation end wall in
a vessel element consisting of only one usually large
and more or less round opening.

Prosenchyma. — A general term of elongated cells
with tapering ends. Note: Used in the past as a
collective term for the fibers and tracheids, and
sometimes the vessel members, as opposed to the
parenchyma.

Secretory structures. Secretions within the
secondary xylem may be intracellular or extracellu-
lar; that is, secretions may remain within the pro-
ducing cells, or be secreted from them. Gums and
resins may be produced in intercellular spaces and
are extracellular in nature, being secreted from
the producing cells. Latices and oils, on the other
hand, are generally produced within cells and are
intracellular.

Intercellular secretory spaces consist of cavities or
canals, which secrete either gum or resin. Inter-
cellular cavities are sacs or pouches surrounded by
a secretory epithelium. Intercellular canals are
more or less elongated spaces, surrounded by a
secretory epithelium and being axial or vertical,
radial or horizontal in disposition. Canals may be
normal or natural or pathologic or traumatic. The

latter is of more frequent occurrence and often
results from breakdown or degeneration of cells
(gummosis).

Intracellular secretory structures consist of lati-
cifers and secretory cells. Laticifers are structures
containing and producing latices (latexes): an artic-
ulated laticiferous tube is a chain of cells in which
the walls separating the cells remain intact, are
perforated, or completely dissolved. These struc-
tures are often called latex vessels because of the
resemblance to prosenchymatous vessels. A non-
articulated laticiferous tube consists of enlarged
tubular cells ramifying throughout the plant axis.
These are single cells which are also called latex
cells, except when they pass through a vascular
ray and are then called latex tubes. Secretory cells
are those cells of nearly normal size, or somewhat
enlarged, that contain oil, resin, or mucilage.

Shape. Pores vary in shape and may be angular
or rounded in cross-section.

Silica. The presence or absence of silica, readily
recognizable because of its characteristic optical
properties, is a very promising criterion for sepa-
rating closely allied genera and species.

Silica occurs in timbers in many forms as inclu-
sions, aggregates, concretions, corpuscles, bodies,
etc. Silica inclusions (refractive index 1.434) refer
to the more common occurrences of silica in which
the granules are smaller than the lumina of the
cells in which they occur, and have a wrinkled or
uneven surface. Vitreous silica (refractive index
1.5) refers to silica that is deposited as a lining on
cell walls or completely fills the lumen of the
containing cell.

Spiral thickening. Helical ridges on the inner
face of and part of the secondary wall. This should
not be confused with microscopic checks. When
spiral thickening is present, the angle of the spiral
is usually less than 45° from the horizontal; that
of spiral checking is steeper.

Storied structures. An arrangement of the
vascular cambium and its derivatives whereby hori-
zontal series of cells or tissues are produced. This
highly specialized condition occurs where there is
little or no apical growth in the cambial derivatives
subsequent to formation, and where the cambial
initials are typically short. This arrangement pro-

SMITHSONIAN CONTRIBUTIONS TO BOTANY

duces the so-called parks in wood, which are visible
to the unaided eye.

Topographic characteristics are classified into
three structural types.

Difjuse-porous: Wood in which the pores are
tairly uniform or only gradually changing size and
distribution throughout a growth ring.

Ring-porous: Wood in which the pores formed
at the beginning of the growth period are much
larger and more numerous than those farther out
in the ring.

Semi-ring-porous: Wood which is intermediate
between the diffuse-porous and ring-porous.

Tylosis. Outgrowths of the cytoplast of ray or
axial parenchyma cells, which penetrate through
the pits of adjacent vessel elements and expand into
these cells. Tyloses may be small and restricted in
size, or they may swell to occlude the vessel lumen;
they may be thin-walled or thick-walled and scle-
rotic, pitted or unpitted. A tylosoid is a swelling
or proliferation of an epithelial cell into an inter-
cellular canal or cavity. Tylosoids may occlude
intercellular spaces. These differ from tyloses in
that they do not pass through pits.

Vascular rays. Ribbon-like aggregates of cells
formed by the vascular cambium (ray initials) that
extend radially into the xylem and phloem. In
hardwoods, vascular rays are entirely pareiicyhma-
tous and carry on vital functions in the sapwood. A
ray that is two or more cells wide is said to be
multiseriate. Uniseriate parts of a muhiseriate ray
are as wide as biseriate or triseriate portions. This
unique condition can be observed in some species
of the Sapotaceae and Rubiaceae. In tangential
section the uniseriate margins of rays (or uniseriate
parts), which separate superimposed multiseriate
parts, are of almost the same width as the multi-
seriate parts.

Abundance of vascular rays may be expressed by
counting the rays along a 1-mm line at right angles
to the axis of the wood, preferably on the tangential
section. Results are expressed as the average num-
ber of rays per mm, as follows: very few (up to 2),
few (2-4), moderately numerous (4-7), numerous
(7-10), or very numerous (over 10).

Ray width may be expressed either in numbers
of cells or in actual dimension. When two or more
definite size classes are present, separate measure-

ments should be expressed in microns, while the
width of multiseriate rays should be given both
in microns and in numbers of cells. Classification of
ray width in millimicrons is as follows: extremely
fine (up to 15pm), fine, very fine (15pm-25pm),
moderately fine (25pm-50pm), medium-sized
(50pm-100pni), moderately broad (100pm-200pm),
broad, very broad (200pm-400pm), and extremely
broad (over 400pm).

Ray height may be expressed in terms of cells
when the average height is not more than 15 cells;
when this amount is exceeded, it is more convenient
to record the ray height in meters. (Separate
measurements should be made on uniseriate and
multiseriate rays.) Classification of ray height is
as follows: extremely low (up to 0.5 mm), very
low (0.5-1 mm), low (1-2 mm), rather low (2-5
mm), moderately high (5 mm-1 cm), high (1-2
cm), very high (2-5 cm), and extremely high (over
5 cm).

Classification of vascular rays of dicotyledons as
determined by structure constitute two classes;
homocellular and heterocellular. A homocellular
ray is a xylem ray composed of cells of the same
morphological type, e.g., all procumbent or all
upright. A heterocellular ray is a xylem ray com-
posed of cells of different morphological types, e.g.,
procumbent, square, or upright cells.

'>'ays: A group of closely placed, small,
narrow xylem rays that appear to the unaided eye
or at low magnification as a single large ray.

Perforated ray cells occur when a vessel passes
tangentially through a vascular ray. This is a fairly
uncommon phenomenon, but occurs in Passiflora-
ceae, as well as in a number of other plant families.

Procumbent ray cell is oriented with its main axis
perpendicular to the axis (grain) or prosencyhma-
tous elements when viewed in radial section.

Ray-vessel pitting occurs between ray cells and
vessel members and is classified by diameter meas-
urements, as follows: fine (< 7pm), medium (7pm-
10pm), or coarse (> 10pm).

Sheath cells are a series of upright cells that
form a sheath around the procumbent cells of
multiseriate rays.

Square ray cells in radial section have more or
less equidimensional sides.

Tile cells are a special type of apparently empty

NUMBER 14

ujjrigln ray cells, which may be approximately the
same height as the procumbent ray cells {Diirio
type) or considerably higher than the procumbent
ray cells [Pteroipertnum type). They occur in
indeterminate horizontal series usually interspersed
among the piocumbent cells. Cells ol this type are
known to occur in certain genera of the Malvales.

Upright ray cell is oriented with its main axis
parallel to the axis (grain) of prosencyhmatous
elements when viewed in radial section.

Vertically fused rays: Two or more rays united
along the margins.

Vk.ssel (Pore). An axial series of cells that have
(o.ilesced to form an articulated, tube-like structure
ol indeterminate length; the pits to congeneric ele-
ments are bordered. The cellular components of a
vessel are known as vessel elements, vessel members,
or vessel segments. The variation in the pattern of
the vessels is one of the most important criteria for
describing woods.

Pore is a term of convenience for the cross-section
of a vessel or vascular tracheid. Pores are classified
by the average number per scjuare mm, as follows:
very lew (up to 2), few (2-5), moderately few
(5-10), moderately numerous (10-20), numerous
(20—10), and very numerous (over 40).

(iounts ol pcjres should be made from more than
10 fields, d’he percentage of pore groupings in any
one of the four classes (defined below) may be
computed as lollows: (1) record the frecjuency of
eac h class ol pore grouping (count solitary pores as
a (lass) in each ol 10 randomly placed microscopic
fields; (2) total the frecjuencies for all classes.

Solitary: A single pore completely surrounded by
other elements.

Pore multiple: A group of two or more pores,
crowded together and flattened along the lines of
contact so as to appear as subdivisions of a single
pore. 'Fhe most common type is the radial pore mul-
tiple in which pores are in radial files with flattened
tangential walls between them. In the pore cluster,
pore grouping is irregular.

Pore chain: A radial series or line of adjacent
solitary pores. 7'his type differs from the radial
[jore nndtijde in having no tangential flattening or
adjacent pores.

Vessel elements vary considerably in shape and
size in clillerent hardwoods, and these characters
can often be studied to best advantage in macerated
wood. There are three bases for measuring the
length of vessel members: (1) main body length,
(2) extreme body length, and (3) total length.
Total length, that is, from tip to tip, is most sig-
nificant, for this distance is a direct reflection of
the length of the fusiform cambial initial from
which the vessel element was derived.

The end walls of vessel elements are the continu-
ous areas of superposed vessel elements. These form
various angles with the grain of the wood which
are more or less characteristic for certain plant
groups. Generally, oblique end wall angles are
associated with primitive plant families whereas
horizontal end walls are indicative of the advanced
specialized condition.

Vessel element lengths are classified as follows:
extremely short (less than 175|.im), short, very
short (175pm-250|.im), moderately short (250|_im-
350pm), medium-sized (350pm-800[im), moder-
ately long (800pm-l lOOpm), long, very long
(1 100|iin-1900[im), and extremely long (over
1900pm).

Although both radial and tangential diameters
of pores are frequently used in descriptions, either
dimension may be employed; however, the tan-
gential diameter is less variable and is preferable.
Diameters are classified as follows: extremely small
(average tangential diameter up to 25pm), small
or very small (25pm-50pm), moderately small
(50pm-100pm), medium-sized (100pm-200pm),
large or moderately large (200pm-300pm ), very
large (300fun— 400pm ), and extremely large (over
400pm).

Vf.sturfd pit. a bordered pit with the pit cavity
wholly or partially lined with projections from
the secondary wall.

☆ U.S. GOVERNMENT PRINTING OFFICE: 1974 546-357/3

)

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