Floral diagram is a graphic representation of
flower structure. It shows the number of floral organs, their arrangement and fusion. Different parts of the flower are represented by their respective symbols. Floral diagrams are useful for flower identification or can help in understanding
angiosperm
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
evolution. They were introduced in the late 19th century and are generally attributed to
A. W. Eichler
August Wilhelm Eichler, also known under his Latinized name, Augustus Guilielmus Eichler (22 April 1839 – 2 March 1887), was a German botanist who developed a new system of classification of plants to reflect the concept of evolution.
His aut ...
.
They are typically used with the
floral formula of that flower to study its
morphology.
History
In the 19th century, two contrasting methods of describing the flower were introduced: the textual
floral formulae and pictorial floral diagrams.
Floral diagrams are credited to
A. W. Eichler
August Wilhelm Eichler, also known under his Latinized name, Augustus Guilielmus Eichler (22 April 1839 – 2 March 1887), was a German botanist who developed a new system of classification of plants to reflect the concept of evolution.
His aut ...
, his extensive work ''Blüthendiagramme''
(1875, 1878) remains a valuable source of information on floral morphology. Eichler inspired later generation of scientists, including
John Henry Schaffner. Diagrams were included e.g. in ''Types of Floral Mechanism''
by
Church (1908). They were used in different textbooks, e.g. ''Organogenesis of Flowers''
'' ''by
Sattler Sattler (German (also Sättler): occupational name for a saddler) may refer to:
People
* Barbara Sattler-Kovacevic (born 1948), Austrian retired slalom canoeist
* Barbara Sattler (philosopher) (born 1974), British philosopher
* Daryl Sattler ( ...
(1973), ''Botanische Bestimmungsübungen''
by Stützel (2006) or ''Plant Systematics''
by Simpson (2010). ''Floral Diagrams''
(2010) by Ronse De Craene followed Eichler’s approach using the contemporary
[ APG II was contemporary at the time of book’s writing.] APG II system.
Basic characteristics and significance
A floral diagram is a schematic cross-section through a young flower.
It may be also defined as “projection of the flower perpendicular to its axis”.
It usually shows the number of floral parts,
[It also shows organs that are not part of the flower, but may be closely associated with it, such as bracts and bracteoles.] their sizes, relative positions and fusion. Different organs are represented by distinguishable symbols, which may be uniform for one organ type, or may reflect concrete
morphology. The diagram may also include symbols that don’t represent physical structures, but carry additional information (e.g.
symmetry
Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...
plane orientation).
There is no agreement on how floral diagrams should be drawn, it depends on the author whether it is just a rough representation, or whether structural details of the flower are included.
Diagrams can describe the
ontogeny of flowers, or can show evolutionary relationships. They can be generalized to show the typical floral structure of a
taxon.
It is also possible to represent (partial)
inflorescences by diagrams.
Substantial amount of information may be included in a good diagram. It can be useful for flower identification or comparison between
angiosperm
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
taxa. Paleontologists can take advantage of diagrams for reconstruction of
fossil flowers. Floral diagrams are also of didactic value.
Orientation
Diagrams are usually depicted with the subtending
bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...
''below'' and the axis ''above'' the flower itself, both in the median line. The axis corresponds to the position of the main
stem
Stem or STEM may refer to:
Plant structures
* Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang
* Stipe (botany), a stalk to support some other structure
* Stipe (mycology), the stem of a mushro ...
relative to a lateral flower.
When a
terminal flower is depicted, the axis is not present and therefore cannot be shown.
Bracteoles, if they are present, are usually drawn on the sides of the diagram.
Symbols used in diagrams
Not only the information contained within diagrams, but also their appearance commonly varies between authors. Just some publications incorporate an overview of used symbols.
Bracts and bracteoles, axes
Bracts and bracteoles are commonly shown as
arc
ARC may refer to:
Business
* Aircraft Radio Corporation, a major avionics manufacturer from the 1920s to the '50s
* Airlines Reporting Corporation, an airline-owned company that provides ticket distribution, reporting, and settlement services
* ...
s. In ''Floral Diagrams'' by Ronse De Craene they consistently have a black fill and a little triangle on the outer side to distinguish them from the perianth. In Eichler’s ''Blüthendiagramme'' their representation alters between diagrams.
The axis relative to the flower is shown as black circle in ''Floral Diagrams''. When inflorescence is depicted, the position of its main stem is illustrated by a crossed circle. Eichler’s depiction of axes alternates between diagrams.
Perianth
Perianth parts are also shown as arcs. They may be colored according to their type. In ''Blüthendiagramme'' the
tepals are usually white with black stroke,
sepals are hatched and
petal
Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...
s are black. Ronse De Craene implies that it may be sometimes impossible to classify the organs, he shows green perianth parts as black and pigmented as white.
Estivation can be accurately shown in the diagram.
Androecium
Stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
s are represented by a cross-section through anthers. In case there are many stamens in the flower, they can be simplified and drawn as circles.
Staminode
In botany, a staminode is an often rudimentary, sterile or abortive stamen, which means that it does not produce pollen.Jackson, Benjamin, Daydon; ''A Glossary of Botanic Terms with their Derivation and Accent''; Published by Gerald Duckworth & Co. ...
s have a small black circle inside or are painted black in ''Floral Diagrams'', Eichler also fills them black.
Gynoecium
The
pistil
Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...
is shown as a sectional view of the
ovary
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...
. Ovary position is highlighted by small triangles in ''Floral Diagrams''. Ronse De Craene also incorporates ovule morphology or shows the position of stigmatic lobes by white shapes.
Nectaries
In ''Floral Diagrams'',
nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
ies are filled by grey color, Eichler fills them by hatching.
Other
Fusion can be shown in diagrams by full connecting lines between organs. Lost organs can be represented by a star (✶), lost perianth parts or bracts/bracteoles can be shown with dashed stroke. It is possible to show the direction of monosymmetry by a large arrow.
Resupination may be illustrated by a curved arrow. Floral parts can be accompanied by numbers to show their sequence of initialization.
Floral diagrams and floral formulae
Each of these two concepts is better in expressing some information. Floral diagrams can show the size and relative position of the organs. On the other hand,
floral formulae are capable of broader generalization. Prenner ''et al.'' view them as complementary methods and state they make an “identikit” flower when utilized together.
Ronse De Craene also approves of their combined use.
Examples
See also
*
Floral formulae
*
Flower
*
Floral organs
*
Dicot flower
*
Monocot flower
*
inflorescence
Notes
References
Bibliography
*
External links
Floral diagram generator
{{botany
Flowers
Plant morphology