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A pseudanthium (Greek for "false flower") is an
inflorescence An inflorescence is a group or cluster of flower A flower, sometimes known as a bloom or blossom Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some ...
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 head, composite flower, or capitulum, which are special types of inflorescences in which anything from a small cluster to hundreds or sometimes thousands of
flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fruit tree, trees (genus ''Prunus'') and of some other plan ...

flower
s are grouped together to form a single flower-like structure. Pseudanthia take various forms. The real flowers (the florets) are generally small and often greatly reduced, but the pseudanthium itself can sometimes be quite large (as in the heads of some varieties of
sunflower ''Helianthus'' () is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), ...

sunflower
). Pseudanthia are characteristic of the daisy and sunflower
family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same Politic ...
(
Asteraceae The family (biology), family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the Order (biology), order Asterales. Commonly referred to as the aster, daisy, composite, o ...

Asteraceae
), whose flowers are differentiated into ray flowers and disk flowers, unique to this family. The disk flowers in the center of the pseudanthium are
actinomorphic Floral symmetry describes whether, and how, a flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fru ...

actinomorphic
and the
corolla Corolla may refer to: *Corolla (botany) upright=1.4, Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals) The perianth (perigonium, perigon or perigone in monocots) is ...
is fused into a tube. Flowers on the periphery are
zygomorphic Floral symmetry describes whether, and how, a flower A flower, sometimes known as a bloom or blossom Image:Cerisier du Japon Prunus serrulata.jpg, Cherry blossoms in Paris in full bloom. In botany, blossoms are the flowers of stone fruit fru ...
and the corolla has one large lobe (the so-called "petals" of a daisy are individual ray flowers, for example). Either ray or disk flowers may be absent in some plants: ''
Senecio vulgaris ''Senecio vulgaris'', often known by the common names groundsel and old-man-in-the-spring, is a flowering plant in the daisy family Asteraceae. It is an annual plant, annual herbaceous plant, herb, native to Europe and widely naturalised as a rud ...

Senecio vulgaris
'' lacks ray flowers and ''
Taraxacum officinale ''Taraxacum officinale'', the dandelion or common dandelion, is a flowering herbaceous Herbaceous plants are vascular plants that have no persistent wood, woody stems above ground, including many perennial plant, perennials, and nearly all An ...

Taraxacum officinale
'' lacks disk flowers. The individual flowers of a pseudanthium in the family Asteraceae (or Compositae) are commonly called ''florets''. The pseudanthium has a whorl of
bract In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Anci ...

bract
s below the flowers, forming an
involucre 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 often (but not always) different from foliage leaves. They may be smaller, ...
. In all cases, a pseudanthium is superficially indistinguishable from a flower, but closer inspection of its anatomy will reveal that it is composed of multiple flowers. Thus, the pseudanthium represents an evolutionary convergence of the inflorescence to a reduced reproductive unit that may function in
pollination Pollination is the transfer of pollen Pollen is a powdery substance consisting of pollen grains which are Sporophyte, microsporophytes of spermatophyta, seed plants, which produce male gametes (sperm cells). Pollen grains have a hard coat ...

pollination
like a single flower, at least in plants that are animal pollinated. Pseudanthia may be grouped into types. The first type has units of individual flowers that are recognizable as single flowers even if fused. In the second type, the flowers do not appear as individual units and certain organs like stamens and carpels can not be associated with any individual flowers.


History

The term pseudanthium was originally applied to flowers with stamens in two whorls with the outer whorl opposite the petals (obdiplostemonate) or polyandric flowers; by the early 1900s the term was repurposed by the advocates of the 'pseudanthium theory' which assumed flower evolution originated from a polyaxail instead of a monoaxial configuration.


Related terms


Synorganization

The collection of independent organs into a complex structure is called '' synorganization''.


Head

''Head'' is an equivalent term for flower head and pseudanthium when used in the botanical sense


Capitulum

''Capitulum'' (plural ''capitula'') can be used as an exact synonym for pseudanthium and flower head; however, its use is generally but not always restricted to the family Asteraceae. At least one source defines it as a small flower head. In addition to its botanical use as a term meaning flower head it is also used to mean the top of the
sphagnum ''Sphagnum'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circu ...

sphagnum
plant.


Calathid

''Calathid'' (plural ''calathids'' or ''calathidia'') is a very rarely used term. It was defined in the 1966 book, ''The genera of flowering plants (Angiospermae)'', as a specific term for a flower head of a plant in the family Asteraceae. However, on-line botanical glossaries do not define it, and
Google Scholar Google Scholar is a freely accessible web search engine A search engine is a software system A software system is a system of intercommunicating software component, components based on forming part of a computer system (a combination of Compu ...
does not link to any significant usage of the term in a botanical sense.


Plant families

Pseudanthia occur in 40 plant families including: *
Adoxaceae Adoxaceae, commonly known as moschatel family, is a small family of flowering plants in the order Dipsacales, now consisting of five genera and about 150–200 species. They are characterised by opposite leaves, opposite toothed leaf, leaves, sma ...

Adoxaceae
— in some ''
Viburnum ''Viburnum'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circum ...

Viburnum
'' spp. *
Apiaceae Apiaceae or Umbelliferae is a family of mostly aromatic flowering plants The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group of land plants The Embryophyta () or land plants are the most fami ...

Apiaceae
— pseudanthia are called ''
umbel In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancie ...
s'' *
Araceae The Araceae are a family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typica ...

Araceae
— pseudanthia are called '' spadices'' *
Asteraceae The family (biology), family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the Order (biology), order Asterales. Commonly referred to as the aster, daisy, composite, o ...

Asteraceae
— The ''capitula'' (singular ''capitulum'') or ''flower heads'', which are collections of different types of flowers, is a pseudanthium. The individual flowers of a capitulum are called ''florets''. Commonly the capitulum has ray flowers specialized to attract pollinators arranged surrounding disc flowers responsible for
sexual reproduction Sexual reproduction is a type of reproduction Reproduction (or procreation or breeding) is the biological process Biological processes are those processes that are vital for an organism In biology, an organism (from Ancient Greek, ...
, perianth symmetry can be varailbe within the family. *
Campanulaceae The family (biology), family Campanulaceae (also bellflower family), of the order (biology), order Asterales, contains nearly 2400 species in 84 genus, genera of herbaceous plant, herbaceous flowering plant, plants, shrubs, and rarely small trees ...
*
Centrolepidaceae Centrolepidaceae are a family (biology), family of flowering plants now included in Restionaceae following APG IV system, APG IV (2016). The botanical name has been recognized by most taxonomists. The APG II system, of 2003 (unchanged from the ...
— Where individual male and female flowers are grouped together and wrapped in bracts forming a pseudanthium appearing as a bisexual flower. *
Cornaceae Cornaceae is a cosmopolitan family of flowering plant Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: ...
*
Cyperaceae The Cyperaceae are a family of graminoid In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in t ...
— In subfamily Mapanioideae, pseudanthia are termed ''spicoids''. In ''
Lepironia ''Lepironia'' is a genus of the sedge family, comprising only one species, ''Lepironia articulata'', known as the grey sedge.Govaerts, R. & Simpson, D.A. (2007). World Checklist of Cyperaceae. Sedges: 1-765. The Board of Trustees of the Royal Bo ...
'' sp the pseudanthium is greatly condensed with staminate flowers surrounding a central terminal pistillate female flower. *
Dipsacaceae The Dipsacaceae have been recognized as a family (the teasel family) of the order Dipsacales The Dipsacales are an order of flowering plant The flowering plants, also known as Angiospermae (), or Magnoliophyta (), are the most diverse group ...
*
Euphorbiaceae The Euphorbiaceae, the spurge ''Euphorbia'' is a very large and diverse genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific st ...

Euphorbiaceae
— pseudanthia are called ''
cyathia A cyathium (plural: cyathia) is one of the specialised Pseudanthium, pseudanthia ("false flowers") forming the inflorescence of plants in the genus ''Euphorbia'' (Euphorbiaceae). A cyathium consists of: * Five (rarely four) bracteoles. These ar ...
'', composed of a single carpal flower with few to many single stamen staminate flowers contained within a cup-shaped structure or bracts; the bracts are often rimmed with
nectar Nectar is a sugar Sugar is the generic name for , soluble s, many of which are used in food. Simple sugars, also called s, include , , and . Compound sugars, also called s or double sugars, are molecules made of two monosaccharides jo ...

nectar
ies and less commonly petal-like structures. The central cyathia maybe composed of all male flowers. *
Eriocaulaceae The Eriocaulaceae are a family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typ ...
*
Hamamelidaceae Hamamelidaceae, commonly referred to as the witch-hazel family, is a family (biology), family of flowering plants in the order Saxifragales. The clade consists of shrubs and small trees positioned within the woody clade of the core Saxifragales. ...
— in '' Rhodoleia'' *
Marcgraviaceae The Marcgraviaceae are a neotropical angiosperm Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: Greece ...
*
Moraceae The Moraceae — often called the mulberry family or fig family — are a family of flowering plants comprising about 38 genera and over 1100 species. Most are widespread in tropical and subtropical regions, less so in temperate climates; however ...

Moraceae
*
Myrtaceae Myrtaceae or the myrtle family is a family of dicotyledon The dicotyledons, also known as dicots (or more rarely dicotyls), are one of the two groups into which all the flowering plant The flowering plants, also known as Angiospermae (), ...
— in '' Actinodium'' — the pseudanthia is a head-like structure with fertile flowers in the center and showy ray-like structures along the outside. *
Nothofagaceae ''Nothofagus'', also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere in southern South America (Chile, Argentina) and Australasia (east and southeast Australia, New Zealand, New Gui ...

Nothofagaceae
in subgenus Lophozonia - a three‐flowered dichasium without branches. *
Nyssaceae Nyssaceae is a family of flowering A flower, sometimes known as a bloom or blossom, is the reproductive Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are p ...
— in '' Davidia'' *
Poaceae Poaceae () or Gramineae () is a large and nearly ubiquitous family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose of families is to maintain ...
*
Pontederiaceae Pontederiaceae is a family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typical ...
— in ''
Hydrothrix ''Hydrothrix'' Joseph Dalton Hooker, Hook.f. was previously a monospecific, monotypic flowering plant genus of Pontederiaceae, but is currently included in a broader and monophyletic ''Heteranthera''. The highly modified ''Heteranthera gardneri' ...
'' *
Proteaceae The Proteaceae form a family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typ ...

Proteaceae
*
Rubiaceae The Rubiaceae are a family In , family (from la, familia) is a of people related either by (by recognized birth) or (by marriage or other relationship). The purpose of families is to maintain the well-being of its members and of soci ...
*
Saururaceae Saururaceae is a plant family comprising four genera and seven species of herbaceous flowering plants native to eastern and southern Asia and North America. The family has been recognised by most taxonomists, and is sometimes known as the "lizard' ...

Saururaceae
— in ''
Anemopsis The monotypic genus ''Anemopsis'' has only one species, ''Anemopsis californica'', with the common names yerba mansa or lizard tail. It is a perennial (plant), perennial herb in the lizard tail family (Saururaceae) and prefers very wet soil or ...

Anemopsis
'' In some families, it is not yet clear whether the "flower" represents a pseudanthium because the anatomical work has not been done (or is still ambiguous due to considerable evolutionary reduction). Possible pseudanthia of this type may occur in the following families: *
Hydatellaceae Hydatellaceae are a family In human society, family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of families is to maintain th ...
*
Lemnaceae Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose fr ...
*
Pandanaceae Pandanaceae is a Family (biology), family of flowering plants native to the tropics and subtropics of the Old World, from West Africa through the Pacific Ocean, Pacific. It contains 982 known species in five Genus, genera, of which the type genus, ...
*
Triuridaceae Triuridaceae are a family of tropical and subtropical flowering plants, including nine genera with a total of ca 55 known species (Christenhusz & Byng 2016 ). All members lack chlorophyll and are mycoheterotrophic (obtain food by digesting intra ...
*
Phyllanthaceae Phyllanthaceae is a Family (biology), family of flowering plants in the eudicot Order (biology), order Malpighiales. It is most closely related to the family Picrodendraceae.Kenneth J. Wurdack and Charles C. Davis. 2009. "Malpighiales phylogeneti ...
Petra Hoffmann, Hashendra S. Kathriarachchi, and Kenneth J. Wurdack. 2006. "A Phylogenetic Classification of Phyllanthaceae (Malpighiales)." ''Kew Bulletin.'' 61(1):40.


Gallery

File:Ubor hoofdie.svg, Diagram of a flower head. Note bracts surrounding the flowers, which would be absent on a capitulum. File:Bellis perennis white (aka).jpg, Flower head of a common daisy (''
Bellis perennis ''Bellis perennis'', the daisy, is a common European species of the family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group shari ...

Bellis perennis
'') File:Flower head.jpg, Flowers open in succession in head of a sunflower (''
Helianthus annuus ''Helianthus annuus'', the common sunflower, is a large annual plant, annual forb of the genus ''Helianthus'' grown as a crop for its edible oil and edible fruits. This sunflower species is also used as wild bird food, as livestock forage (as a m ...

Helianthus annuus
''), with ray florets forming the 'petals' File:Hieracium 2007-1.jpg, Close up of the ray corolla of '' Hieracium lachenalii''; every "petal" is actually a separate five-petaled flower complete with its own stamens and making its own fruit. File:EricameriaNauseosa 8691.JPG, Discoid (having only disk flowers) flower heads of ''
Ericameria nauseosa ''Ericameria nauseosa'' (formerly ''Chrysothamnus nauseosus''), commonly known as Chamisa, rubber rabbitbrush, and gray rabbitbrush, is a North American shrub in the Asteraceae, sunflower family (Aster). It grows in the arid regions of western ...

Ericameria nauseosa
'' (rubber rabbitbrush) File:Senecio_angulatus_kz11.jpg, Flower head of creeping groundsel (''
Senecio angulatus ''Senecio angulatus'', also known as creeping groundsel and Cape ivy, is a Succulent plant, succulent flowering plant in the daisy family that is native to South Africa. Cape ivy is a scrambling and a vine, twining herb that can become an Noxiou ...

Senecio angulatus
'') with petaloid ray florets and tubular disc florets in the middle


References

{{Reflist
Plant morphology ''Plant morphology'' is the field in botany that studies the diversity in forms, with the naked eye or slight optical magnification. This is opposed to plant anatomy (see :Plant anatomy) that needs to cut into plants to be able to study its subject, ...
Flowers