This document provides guidelines for describing bark, including 10 key items: 1) Name, 2) Origin, 3) Condition, 4) Size, 5) Color, 6) Shape, 7) Outer surface features, 8) Inner surface, 9) Fracture characteristics, and 10) Histology. The guidelines describe how to document characteristics such as color, texture, markings, and how it breaks to provide a full description of bark samples.

1. BarkFirst year practical
course (Botany 1)
Presented by:
Shimaa Abdelgawad
Assisting lecturer at
Pharmacognosy
department, Faculty of
pharmacy, Fayoum
University

2. Definition of BarkDefinition of Bark
• Bark is the portion of the
trunk, stem, branches or
roots of woody plants
exterior to the cambium
• It include all the tissues
outside the cambium.

3. General scheme for description of bark
1. Name: English, Latin and Arabic names.
2. Origin: condition, part used, genus,
species and family.
3. Condition: fresh or dry; entire or broken
pieces.pieces.
4. Size: measure height, width and thickness.
5. Color: as seen in bulk.

4. General scheme for description of bark
6. Shapes or forms of bark:
Shape of the bark depends on the distribution
and nature of the tissues present and upon the
method of separation and removal of the parkmethod of separation and removal of the park
from the plant

5. 6. Shapes or forms of bark:
1- Flat: When derived from old trunk. It is
usually quite flat and very thick
2- Curved: When curved and slightly
concave on the inner side
3- Recurved: When the concave side is
the outer one
4- Channeled: When deeply concave on
the inner side
1
2
4
the inner side
5- Single quill: When deeply concave on
the inner side that the edges of the bark
nearly or quite overlap.
6- Double quill: When both edges are
separately in rolled
7- Compound quill: When single or
double quills are packed inside one
another
5 6
7

6. :7. Outer surface
In this item, describes the color of outer
surface of park and any features present like:
• Lenticels
• Epiphytes: lichens, liverworts or mosses• Epiphytes: lichens, liverworts or mosses
• Touch: the park may be smooth or showing
longitudinal or transverse furrows or showing
cracks or fissures.

7. :7. Outer surface
Lenticels: Placed transversely, the shape and
abundance of which may help in distinguishing
the bark. Lenticels, are breathing pores for
exchange of gases, larger in size and smaller in
number than stomata.number than stomata.

8. :7. Outer surface
Lichens:
• A type of fungus that grows on the
surface of barks.
• It exists as a grayish thalloid structure.
• Grow on trees using the bark as a
medium for their nutrition and growth.
Liverworts:
• Are foliaceous structure.
• Consists of very small stems to which
small leaves are attached in one plane.
Mosses:
Are stem bearing spirally arranged leaves
each possesses a midrib and lamina of
one cell thick.

9. :7. Outer surface
Touch
1- Cracks and fissures: arise owing to
continued increase in growth and to
the lack elasticity.
2- Wrinkles and furrows: The greater
shrinkage of the softer tissues result
in formation of wrinkles (becausein formation of wrinkles (because
the shrinkage of the barks during
drying occur chiefly transversely.
3- Smooth: when the cork is evenly
developed (or younger trees).
4- It may be scaly due to exfoliation of
the outer tissues
Cracks and fissures
Wrinkles and furrows

10. :8. Inner surface
It is usually paler in color than outer surface and
can be described as:
1- Smooth: due to the presence of uniform soft
inner tissue
2- Striated: when showing fine or coarse parallel2- Striated: when showing fine or coarse parallel
longitudinal ridges, produced as a result of
transverse shrinkage
3- Corrugated: when showing transverse parallel
wrinkles or folds produced as a result of
longitudinal shrinkage

11. 9. Fracture
This term describes how the barks broken
transversely and the character of the broken
surface.
It is described as:
1- Short: When the fractured surface is smooth.
2- Splintery: When sharp and jagged projection are
formed.
Splintery
3- Fibrous: When fine fibrous threads extend from
the broken surface.
4- Granular: When the surface exhibit small rounded
prominences.
5- Horny: When hard to broken and exhibiting hard
horn like broken surface.
6- Laminated: When breaks into arranged layers.
7- Flexible: When breaking only by tearing or
twisting.
Fibrous
Laminated

12. 10- Histology of bark

13. General scheme for description of bark
1. Name: English, Latin and Arabic names.
2. Origin: condition, part used, genus,
species and family.
3. Condition: fresh or dry; entire or broken
pieces.pieces.
4. Size: measure height, width and thickness.
5. Color: as seen in bulk.

14. General scheme for description of bark
1. Name: English, Latin and Arabic names.
2. Origin: condition, part used, genus,
species and family.
3. Condition: fresh or dry; entire or broken
pieces.pieces.
4. Size: measure height, width and thickness.
5. Color: as seen in bulk.