Floral Diagram
Floral Diagram
Floral Diagram
FloraldiagramofAnagallisarvensis.[1]:307Thedotrepresentsthemain
axis,greenstructurebelowisthesubtendingbract.Calyx(greenarcs)
consistsoffivefreesepals;corolla(redarcs)consistsoffive
fusedpetals.Antepetalousstamensarejoinedtopetalsbyhairy
filaments.Ovaryissuperior,placentationisfreecentraland
theovulesareatropous.
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 evolution. They
were introduced in the late 19th century and are generally attributed to A. W. Eichler.[1]
Contents
[hide]
1History
3Orientation
4.2Perianth
4.3Androecium
4.4Gynoecium
4.5Nectaries
4.6Other
6Examples
7See also
8Notes
9References
10External links
History[edit]
In the 19th century, two contrasting methods of describing the flower were introduced: the textual floral
formulae and pictorial floral diagrams.[2] Floral diagrams are credited to A. W. Eichler, his extensive
work Blthendiagramme[3][4] (1875, 1878) remains a valuable source of information on floral morphology.
Eichler inspired later generation of scientists, diagrams were included e.g. in Types of Floral
Mechanism[5] by Church(1908). They were used in different textbooks, e.g. Organogenesis of
Flowers[6] by Sattler (1973), Botanische Bestimmungsbungen[7] by Sttzel (2006) or Plant
Systematics[8] by Simpson (2010). Floral Diagrams[1](2010) by Ronse De Craene followed Eichlers
approach using the contemporary[Note 1] APG II system.
Floral diagram is a schematic cross-section through a young flower.[1] It may be also defined as
projection of the flower perpendicular to its axis.[3] It usually shows the number of floral parts,[Note 2] 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 dont represent physical structures, but carry additional information (e.g. symmetry 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.[1]:37 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 taxa. Paleontologists can take advantage of diagrams
for reconstruction of fossil flowers. Floral diagrams are also of didactic value.[1]:xiii
Relation of a plant material (Campanula medium) to the floral diagram. Black dashed line shows
the cross-section. 1 position of the main axis; 2 cross-section through the lateral flower; 3
bracteole; 4 subtending bract.
Orientation[edit]
Diagrams are usually depicted with the subtending bract below and the axis above the flower itself, both
in the median line. The axis corresponds to the position of the main stem relative to a lateral flower.
[9]:12
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.
RonseDeCraene
Eichler
inconsistent
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. Eichlers depiction of axes
alternates between diagrams.
RonseDeCraene
Eichler
axisrelativetotheflower
inconsistent
mainstemofaninflorescence
Perianth[edit]
Perianth parts are also shown as arcs. They may be colored according to their type.
In Blthendiagramme the tepals are usually white with black stroke, sepals are hatched and petals 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.
RonseDeCraene
tepals
Eichler
forsepalsorsepaloid
fortepals
forsepals
tepals/sepals
forpetalsorpetaloid
Androecium[edit]
forpetals
Stamens 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. Staminodes have a small black circle inside or are
painted black in Floral Diagrams, Eichler also fills them black.
RonseDeCraene
stamen
staminode
Eichler
or
or
Gynoecium[edit]
The pistil is shown as a sectional view of the ovary. 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.
RonseDeCraene
superiorovary
inferiorovary
Eichler
halfinferiorovary
Nectaries[edit]
In Floral Diagrams, nectaries are filled by grey color, Eichler fills them by hatching.
Other[edit]
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 inicialization.
Examples[edit]
PartialinflorescenceofTheobromacacao(afterRonse
DeCraene).
Floralformula:K5C5A(5+5)G(5)
FloraldiagramofPyrus
communis(afterEichler).
Floralformula:K(5)C5
A10+5+5(4)
See also[edit]
Floral formulae
Notes[edit]
1.
2.
References[edit]
1.
2.
3.
4.
5.
Jump up^ Church, Arthur Harry (1908). Types of floral mechanism; a selection of
diagrams and descriptions of common flowers arranged as an introduction to the
systematic study of angiosperms. Oxford: Clarendon Press.
6.
Jump up^ Sattler, Rolf (1973). Organogenesis of flowers; a photographic textatlas. Toronto, Buffalo: University of Toronto Press. ISBN 0-8020-1864-5.
7.
8.
Jump up^ Simpson, Michael George (2010). Plant Systematics. Oxford (Great
Britain): Academic Press. ISBN 978-0-12-374380-0.
9.