Floral diagram

Last updated
Anagallis arvensis 2.jpg
Floral diagram - Anagallis arvensis.svg
Floral diagram of Anagallis arvensis . [1] :307 The dot represents the main axis, green structure below is the subtending bract. Calyx (green arcs) consists of five free sepals; corolla (red arcs) consists of five fused petals. Antepetalous stamens are joined to petals by hairy filaments. Ovary is superior, placentation is free central and the ovules are atropous.

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

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. [2] Floral diagrams are credited to A. W. Eichler, whose extensive work Blüthendiagramme [3] [4] (1875, 1878) remains a valuable source of information on floral morphology. Eichler inspired later generation of scientists, including John Henry Schaffner. [5] Diagrams were included e.g. in Types of Floral Mechanism [6] by Arthur Church (1908). They were used in different textbooks, e.g. Organogenesis of Flowers [7] by Rolf Sattler (1973), Botanische Bestimmungsübungen [8] by Stützel (2006) or Plant Systematics [9] by Simpson (2010). Floral Diagrams [1] (2010) by Ronse De Craene followed Eichler’s approach using the contemporary [Note 1] APG II system.

Basic characteristics and significance

A 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 don’t 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.

A 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. Floral diagram and plant material.svg
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

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. [10] :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.

Symbols used in diagrams

Not only the information contained within diagrams, but also their appearance commonly varies between authors. Some publications include an overview of symbols used.

Bracts and bracteoles, axes

Bracts and bracteoles are commonly shown as arcs. 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.

Ronse De CraeneEichler
Black ark with a triangle.svg 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. Eichler’s depiction of axes alternates between diagrams.

Ronse De CraeneEichler
axis relative to the flower Axis C.svg inconsistent
main stem of an inflorescence Axis C inflorescence.svg

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 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.

Ronse De CraeneEichler
Black ark.svg for sepals or sepaloid tepals

White ark.svg for petals or petaloid tepals/sepals

White ark.svg for tepals

Pointed hatched ark.svg for sepals Black ark.svg for petals

Androecium

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.

Ronse De CraeneEichler
stamen Stamen Craene.svg or Stamen Craene2.svg Stamen Eichler.svg
staminode Staminode Craene.svg or Staminode Craene 2.svg Staminode Eichler.svg

Gynoecium

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.

Ronse De CraeneEichler
superior ovary Gynoecium C superior.svg Gynoecium E superior.svg
inferior ovary Gynoecium C inferior.svg
half-inferior ovary Gynoecium C half-inferior.svg

Nectaries

In Floral Diagrams, nectaries 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. [2] :248 Ronse De Craene also approves of their combined use. [1] :xiii

Examples

Partial inflorescence of Theobroma cacao Floral diagram -- theobroma cacao.svg
Partial inflorescence of Theobroma cacao
Floral diagram of Pyrus communis Floral diagram -- Pyrus communis.svg
Floral diagram of Pyrus communis
Partial inflorescence of Theobroma cacao (after Ronse De Craene).
Floral formula: ✶ K5 C5 A(5°+5²) G(5)
Floral diagram of Pyrus communis (after Eichler).
Floral formula: ✶ K(5) C5 A10+5+5 Ğ(4)

See also

Notes

  1. APG II was contemporary at the time of book’s writing.
  2. It also shows organs that are not part of the flower, but may be closely associated with it, such as bracts and bracteoles.

Related Research Articles

<span class="mw-page-title-main">Inflorescence</span> Term used in botany to describe a cluster of flowers

An inflorescence, in a flowering plant, is a group or cluster of flowers arranged on a stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a main axis (peduncle) and by the timing of its flowering.

<i>Amborella</i> Species of shrub

Amborella is a monotypic genus of understory shrubs or small trees endemic to the main island, Grande Terre, of New Caledonia in the southwest Pacific Ocean. The genus is the only member of the family Amborellaceae and the order Amborellales and contains a single species, Amborella trichopoda. Amborella is of great interest to plant systematists because molecular phylogenetic analyses consistently place it as the sister group to all other flowering plants, meaning it was the earliest group to evolve separately from all other flowering plants.

<span class="mw-page-title-main">Tepal</span> One of the outer parts of a flower

A tepal is one of the outer parts of a flower. The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated, as in Magnolia, or because, although it is possible to distinguish an outer whorl of sepals from an inner whorl of petals, the sepals and petals have similar appearance to one another. The term was first proposed by Augustin Pyramus de Candolle in 1827 and was constructed by analogy with the terms "petal" and "sepal".

<span class="mw-page-title-main">Bract</span> Modified or specialized leaf

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 a different color, shape, or texture. Typically, they also look different from the parts of the flower, such as the petals or sepals. A plant having bracts is referred to as bracteate or bracteolate, while one that lacks them is referred to as ebracteate and ebracteolate, without bracts.

<span class="mw-page-title-main">Floral symmetry</span> Shape of flowers

Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts.

<span class="mw-page-title-main">Commelinaceae</span> Family of flowering plants

Commelinaceae is a family of flowering plants. In less formal contexts, the group is referred to as the dayflower family or spiderwort family. It is one of five families in the order Commelinales and by far the largest of these with about 731 known species in 41 genera. Well known genera include Commelina (dayflowers) and Tradescantia (spiderworts). The family is diverse in both the Old World tropics and the New World tropics, with some genera present in both. The variation in morphology, especially that of the flower and inflorescence, is considered to be exceptionally high amongst the angiosperms.

<span class="mw-page-title-main">Trochodendraceae</span> Family of flowering plants

Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species along with up to five additional extinct genera and a number of extinct species. The living species are native to south east Asia. The two living species both have secondary xylem without vessel elements, which is quite rare in angiosperms. As the vessel-free wood suggests primitiveness, these two species have attracted much taxonomic attention.

<span class="mw-page-title-main">August W. Eichler</span> German botanist (1839-1887)

August Wilhelm Eichler, also known under his Latinized name, Augustus Guilielmus Eichler, was a German botanist who developed a new system of classification of plants to reflect the concept of evolution. His author abbreviation in botany is Eichler.

<span class="mw-page-title-main">Rafflesiaceae</span> Family of flowering plants

The Rafflesiaceae are a family of rare parasitic plants comprising 36 species in 3 genera found in the tropical forests of east and southeast Asia, including Rafflesia arnoldii, which has the largest flowers of all plants. The plants are endoparasites of vines in the genus Tetrastigma (Vitaceae) and lack stems, leaves, roots, and any photosynthetic tissue. They rely entirely on their host plants for both water and nutrients, and only then emerge as flowers from the roots or lower stems of the host plants.

<span class="mw-page-title-main">Flower</span> Reproductive structure in flowering plants

A flower, also known as a bloom or blossom, is the reproductive structure found in flowering plants. Flowers consist of a combination of vegetative organs – sepals that enclose and protect the developing flower, petals that attract pollinators, and reproductive organs that produce gametophytes, which in flowering plants produce gametes. The male gametophytes, which produce sperm, are enclosed within pollen grains produced in the anthers. The female gametophytes are contained within the ovules produced in the carpels.

<i>Tricyrtis</i> Genus of flowering plants

Tricyrtis is a genus of Asian flowering plants in the lily family, with approximately 20 known species. The species are commonly known in English as toad lilies. The genus has a native range from the Himalayas to eastern Asia, including China, Japan, Philippines and Taiwan, and a few species are cultivated for their ornamental qualities in other parts of the world.

<span class="mw-page-title-main">Pseudanthium</span> Type of inflorescence, clusters of flowers

A pseudanthium is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, composite flowers, or capitula, which are special types of inflorescences in which anything from a small cluster to hundreds or sometimes thousands of flowers are grouped together to form a single flower-like structure. Pseudanthia take various forms. The real flowers are generally small and often greatly reduced, but the pseudanthium itself can sometimes be quite large.

This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.

This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.

<span class="mw-page-title-main">Floral formula</span> Notation representing flowers structure

A floral formula is a notation for representing the structure of particular types of flowers. Such notations use numbers, letters and various symbols to convey significant information in a compact form. They may represent the floral form of a particular species, or may be generalized to characterize higher taxa, usually giving ranges of numbers of organs. Floral formulae are one of the two ways of describing flower structure developed during the 19th century, the other being floral diagrams. The format of floral formulae differs according to the tastes of particular authors and periods, yet they tend to convey the same information.

<span class="mw-page-title-main">Anthospermeae</span> Tribe of plants

Anthospermeae is a tribe of flowering plants in the family Rubiaceae and contains 208 species in 12 genera. Its representatives are found in the Southern Hemisphere, with the exception of the two species of the genus Phyllis. At least two genera, namely Coprosma and Galopina are anemophilous.

<span class="mw-page-title-main">Pentapetalae</span> Group of eudicots known as core eudicots

In phylogenetic nomenclature, the Pentapetalae are a large group of eudicots that were informally referred to as the "core eudicots" in some papers on angiosperm phylogenetics. They comprise an extremely large and diverse group that accounting about 65% of the species richness of the angiosperms, with wide variability in habit, morphology, chemistry, geographic distribution, and other attributes. Classical systematics, based solely on morphological information, was not able to recognize this group. In fact, the circumscription of the Pentapetalae as a clade is based on strong evidence obtained from DNA molecular analysis data.

<i>Berberidopsis beckleri</i> Species of flowering plant

Berberidopsis beckleri is a species of climbing plant found in cool rainforests in eastern Australia. Its common name is the montane tape vine. Ferdinand von Mueller described the plant as Streptothamnus beckleri from collections at the Clarence River.

The floral axis is the area of the flower upon which the reproductive organs and other ancillary organs are attached. It is also the point at the center of a floral diagram. Many flowers in division Angiosperma appear on floral axes. The floral axis can differ in form depending on the type of plant. For example, monocotyledons have a weakly developed floral axis compared to dicotyledons, and will therefore rarely possess a floral disc, which is common among dicotyledons.

<span class="mw-page-title-main">Floral morphology</span>

In botany, floral morphology is the study of the diversity of forms and structures presented by the flower, which, by definition, is a branch of limited growth that bears the modified leaves responsible for reproduction and protection of the gametes, called floral pieces.

References

  1. 1 2 3 4 5 6 7 Ronse De Craene, Louis P. (2010-02-04). Floral Diagrams: An Aid to Understanding Flower Morphology and Evolution. Cambridge: Cambridge University Press. ISBN   978-0-521-49346-8.
  2. 1 2 Prenner, Gerhard; Richard M. Bateman; Paula J. Rudall (February 2010). "Floral formulae updated for routine inclusion in formal taxonomic descriptions". Taxon. 59 (1): 241–250. doi:10.1002/tax.591022. ISSN   0040-0262.
  3. 1 2 Eichler, August Wilhelm (1875). Blüthendiagramme, erster Theil: Enthaltend Einleitung, Gymnospermen, Monocotylen und sympetale Dicotylen. Leipzig: Wilhelm Engelmann.
  4. Eichler, August Wilhelm (1878). Blüthendiagramme, zweiter Theil: Enthaltend die apetalen und choripetalen Dicotylen. Leipzig: Wilhelm Engelmann.
  5. Schaffner 1916.
  6. 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.
  7. Sattler, Rolf (1973). Organogenesis of flowers; a photographic text-atlas. Toronto, Buffalo: University of Toronto Press. ISBN   0-8020-1864-5.
  8. Stützel, Thomas (2006). Botanische Bestimmungsübungen: Praktische Einführung in die Pflanzenbestimmung (2nd ed.). Stuttgart (Hohenheim): UTB, Stuttgart. ISBN   9783825282202.
  9. Simpson, Michael George (2010). Plant Systematics. Oxford (Great Britain): Academic Press. ISBN   978-0-12-374380-0.
  10. Weberling, Focko (1992). Morphology of Flowers and Inflorescences. Cambridge: Cambridge University Press. ISBN   9780521438322.

Bibliography