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Pseudanthium
 
 
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A pseudanthium (Greek for "false flower") or flower head is a special type of inflorescence
Inflorescence

An inflorescence is a group or cluster of flowers arranged on a Plant stem that is composed of a main branch or a complicated arrangement of branches....
, in which several flower
Flower

A flower, sometimes known as a bloom or blossom, is the reproduction structure found in flowering plants . The biological function of a flower is to mediate the union of male sperm with female ovum in order to produce seeds....
s are grouped together to form a flower-like structure. The real flowers are generally small and greatly reduced, but can sometimes be quite large (as in the sunflower
Sunflower

The sunflower is an annual plant in the family Asteraceae and native to the Americas, with a large flowering head . The stem can grow as high as 3 meters , and the flower head can reach 30 cm in diameter with the "large" seeds....
 flower-head). Pseudanthia take various forms.

Pseudanthia are characteristic of the subflower family (Asteraceae
Asteraceae

The family Asteraceae or Compositae is the largest family of flowering plants, in terms of number of species.The name 'Asteraceae' is derived from the type genus Aster , while 'Compositae', an older but still valid name, means composite and refers to the characteristic inflorescence, a special type of pseudanthium found in o...
), where they are called calathidia, calathids or capitula.






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A pseudanthium (Greek for "false flower") or flower head is a special type of inflorescence
Inflorescence

An inflorescence is a group or cluster of flowers arranged on a Plant stem that is composed of a main branch or a complicated arrangement of branches....
, in which several flower
Flower

A flower, sometimes known as a bloom or blossom, is the reproduction structure found in flowering plants . The biological function of a flower is to mediate the union of male sperm with female ovum in order to produce seeds....
s are grouped together to form a flower-like structure. The real flowers are generally small and greatly reduced, but can sometimes be quite large (as in the sunflower
Sunflower

The sunflower is an annual plant in the family Asteraceae and native to the Americas, with a large flowering head . The stem can grow as high as 3 meters , and the flower head can reach 30 cm in diameter with the "large" seeds....
 flower-head). Pseudanthia take various forms.

Pseudanthia are characteristic of the subflower family (Asteraceae
Asteraceae

The family Asteraceae or Compositae is the largest family of flowering plants, in terms of number of species.The name 'Asteraceae' is derived from the type genus Aster , while 'Compositae', an older but still valid name, means composite and refers to the characteristic inflorescence, a special type of pseudanthium found in o...
), where they are called calathidia, calathids or capitula. The flowers are differentiated into ray and disk flowers, which are unique to the family. The disk flowers in the center of the pseudanthium (called a flower head or capitulum
Capitulum

The term Capitulum can refer to several things:*In botany, a type of flower head where the bracts are located under the basis, such as a Daisy's...
 in Asteraceae) are actinomorphic and the corolla is fused into a tube. Flowers on the periphery are zygomorphic 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 lacks ray flowers and Taraxacum officinale
Taraxacum officinale

Taraxacum officinale, commonly called Dandelion, is a herbaceous perennial plant of the family Asteraceae . It can be found growing in temperate regions of the world, in lawns, on roadsides, on disturbed banks and shores of water ways, and other areas with moist soils....
 lacks disk flowers. The capitulum has a whorl of bract
Bract

In botany, a bract is a modified or specialized leaf. Bracts are ordinarily associated with reproductive structures . They are ordinarily reduced in size relative to foliage leaves, or of a different color or texture from foliage leaves, or both....
s below the flowers, forming an involucre.

In all cases, a pseudanthium (inflorescence) 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

Pollination in flowering plants and gymnosperms is the process that transfers pollen, which contain the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself....
 like a single flower, at least in plants that are animal pollinated.

Pseudanthia occur in the following plant families:

  • Apiaceae
    Apiaceae

    The Apiaceae or Umbelliferae is a family of usually aromatic plants with hollow stems, commonly known as umbellifers. It includes cumin, parsley, carrot, coriander/cilantro, dill, caraway, fennel, parsnip, celery, Queen anne's lace and other relatives....
  • Asteraceae
    Asteraceae

    The family Asteraceae or Compositae is the largest family of flowering plants, in terms of number of species.The name 'Asteraceae' is derived from the type genus Aster , while 'Compositae', an older but still valid name, means composite and refers to the characteristic inflorescence, a special type of pseudanthium found in o...
  • Campanulaceae
    Campanulaceae

    The family Campanulaceae , of the order Asterales, contains about 70 genus and 2000 species. They are mostly herbs, shrubs, and more rarely small trees, which usually have milky non-toxic sap....
  • Centrolepidaceae
    Centrolepidaceae

    Centrolepidaceae is a botanical name for a family of flowering plants. Such a family has been recognized by most taxonomists.The APG II system, of 2003 , also recognises such a family, and assigns it to the order Poales in the clade commelinids in the monocots....
  • Cornaceae
    Cornaceae

    The Dogwood family is a widespread family, mostly in the north temperate zone, in the order Cornales. The family mostly comprises woody shrubs and trees, in about fifteen genera, although which genera properly belong to this family is controversial....
  • Cyperaceae
    Cyperaceae

    The family Cyperaceae, or the sedges, is a taxon of monocotyledon flowering plants that superficially resemble Poaceae or Juncaceae. The family is large, with some 4,000 species described in about 70 genera....
  • Dipsacaceae
    Dipsacaceae

    The Dipsacaceae, or teasel family, of the order Dipsacales contains 350 species of perennial or biennial herbs and shrubs in eleven genera....
  • Euphorbiaceae
    Euphorbiaceae

    The Spurge family is a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees....
     - there the pseudanthia are called cyathia
    Cyathium

    The very special Pseudanthium in the genus Euphorbia are known as Cyathia. A cyathium consists of:* five bracteoles. These are small, united bracts, which form a cup-like involucre....
  • Eriocaulaceae
    Eriocaulaceae

    The Eriocaulaceae or pipewort family is a family of monocotyledonous flowering plants in the order Poales. The family is large, with about 1,150-1,200 species described in ten genera....
  • Hamamelidaceae
    Hamamelidaceae

    The Hamamelidaceae is a family of flowering plants in the order Saxifragales, including 27 genera and about 80-90 species, all shrubs and small trees....
  • Moraceae
    Moraceae

    Morus-alba.jpgMoraceae ? often called the mulberry family or fig family ? is a family of flowering plants comprising about 40 genera and over 1000 species....
  • Poaceae
    Poaceae

    Poaceae or Gramineae is a family in the Class Liliopsida of the Magnoliophyta. Plants of this family are usually called grasses; the shrub- or tree-like plants in this family are called bamboo ....
  • Pontederiaceae
    Pontederiaceae

    Pontederiaceae is the botanical name of a family of flowering plants.The APG II system, of 2003 places the family in the order Commelinales, in the commelinid clade, in the monocots....
     -- in Hydrothrix
  • Proteaceae
    Proteaceae

    Proteaceae is a family of flowering plants. Mainly restricted to the Southern Hemisphere, it is a fairly large family, with around 80 genus but fewer than 2000 species....
  • Rubiaceae
    Rubiaceae

    Rubiaceae is a family of flowering plants, variously called the madder family, bedstraw family or Coffea family. Other common plants included here are gardenia, cinchona, sweet woodruff, Mitchella, uncaria, ixora, and noni....
  • Saururaceae
    Saururaceae

    Saururaceae is a plant family comprising four genera and six species of herbaceous flowering plants native to eastern and southern Asia and North America....
     -- in 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

    Hydatellaceae is the botanical name for a family of flowering plants containing the genus Trithuria, which has been recently re-classified to include the genus Hydatella....
  • Lemnaceae
    Lemnaceae

    Lemnaceae is a family of flowering plants, also known as the duckweed family, as it contains the duckweeds or water lentils. Since duckweeds are now considered to be a branch of the arum or aroid family , the name 'Lemnaceae' is rapidly falling out of use among taxonomists, who treat it as a subfamily called Lemnoideae....
  • Pandanaceae
    Pandanaceae

    Pandanaceae is a family of flowering plants native to the tropics of the Old World. Such a family has been widely recognized by taxonomists.The APG II system, of 2003 , also recognizes this family, and assigns it to the order Pandanales in the clade monocots....
  • Triuridaceae
    Triuridaceae

    Triuridaceae is a family of flowering plants. Such a family has been recognized by relatively few taxonomists.The APG II system, of 2003, does recognize such a family and places it in the order Pandanales, in the clade monocots....