Editing Inflorescence (section)

==Organization==
There is no general consensus in defining the different inflorescences. The following is based on [[Focko Weberling]]'s ''Morphologie der Blüten und der Blütenstände'' (Stuttgart, 1981). The main groups of inflorescences are distinguished by branching. Within these groups, the most important characteristics are the intersection of the axes and different variations of the model. They may contain many flowers ('''pluriflor''') or a few ('''pauciflor'''). Inflorescences can be '''simple''' or '''compound'''.

===Simple inflorescences===
[[File:Sunflower macro wide.jpg|thumb|Inflorescence of sessile disc florets forming the [[Head (botany)|capitulum]]]]

====Indeterminate or racemose====
Indeterminate simple inflorescences are generally called '''racemose''' {{IPAc-en|ˈ|r|æ|s|ᵻ|m|oʊ|s}}. The main kind of racemose inflorescence is the '''raceme''' ({{IPAc-en|ˈ|r|æ|s|iː|m}}, from classical Latin ''racemus'', [[cluster of grapes]]).<ref>Oxford English Dictionary. Raceme 2. Bot. A type of inflorescence in which the flowers are arranged on short, nearly equal, lateral pedicels, at equal distances along a single elongated axis</ref> The other kind of racemose inflorescences can all be derived from this one by dilation, compression, swelling or reduction of the different axes. Some passage forms between the obvious ones are commonly admitted.
* A '''[[raceme]]''' is an unbranched, [[indeterminate growth|indeterminate]] inflorescence with pedicellate (having short floral stalks) flowers along the axis.
* A '''[[raceme|spike]]''' is a type of raceme with flowers that do not have a pedicel.
* A racemose '''[[corymb]]''' is an unbranched, indeterminate inflorescence that is flat-topped or convex due to their outer pedicels which are progressively longer than inner ones.
* An '''[[umbel]]''' is a type of raceme with a short axis and multiple floral pedicels of equal length that appear to arise from a common point. It is characteristic of [[Umbelliferae]].
* A '''[[spadix (botany)|spadix]]''' is a spike of flowers densely arranged around it, enclosed or accompanied by a highly specialised bract called a '''[[spadix (botany)|spathe]]'''. It is characteristic of the family [[Araceae]].
* A '''[[Pseudanthium|flower head]]''' or '''capitulum''' is a very contracted raceme in which the single sessile flowers share are borne on an enlarged stem. It is characteristic of [[Dipsacaceae]].
* A '''[[catkin]]''' or '''ament''' is a scaly, generally drooping spike or raceme. Cymose or other complex inflorescences that are superficially similar are also generally called thus.

<gallery>
Image:Traube (inflorescence).svg|[[Raceme]]
Image:Epilobe feuilles etroites 01.jpg|''[[Epilobium angustifolium]]''
Image:Inflorescences Spike Kwiatostan Kłos.svg|Spike
Image:Plantagomedia.JPG|''[[Plantago media]]'' (spike)
Image:Schirmtraube (inflorescence).svg| Racemose [[corymb]]
Image:Schleifenblume06.jpg|''[[Iberis umbellata]]'' (racemose corymb)
Image:Inflorescences Umbel Kwiatostan Baldach.svg|[[Umbel]]
Image:Astrantia minor.jpg|''[[Astrantia minor]]'' (umbel)
Image:Kolben (inflorescence).svg|[[Spadix (botany)|Spadix]]
Image:Arum maculatum.jpeg|''[[Arum maculatum]]'' (spadix)
Image:Koepfchen (inflorescence).svg|[[Pseudanthium|Head]] (round)
Image:Fleur 9 - VTdJ.JPG|''[[Dipsacus fullonum]]'' (head)
Image:Kaetzchen (inflorescence).svg|[[Catkin]] (racemose or spicate)
Image:Alnus incana rugosa catkin.jpg|''[[Alnus incana]]'' (ament)
</gallery>

====Determinate or cymose====
{{Anchor|cyme|cymose}}
Determinate simple inflorescences are generally called '''cymose'''. The main kind of cymose inflorescence is the '''cyme''' (pronounced {{IPAc-en|s|aɪ|m}}), from the Latin ''cyma'' in the sense 'cabbage sprout', from Greek ''kuma'' 'anything swollen').<ref>Collins English Dictionary. 8th Edition first published in 2006</ref><ref>Oxford English Dictionary. Cyme(1) Bot. A species of inflorescence wherein the primary axis bears a single terminal flower which develops first, the system being continued by axes of secondary and higher orders which develop successively in like manner; a centrifugal or definite
inflorescence: opposed to [[Raceme]]. Applied esp. to compound inflorescences of this type forming a more or less flat head.</ref> Cymes are further divided according to this scheme:
* Only one secondary axis: '''monochasium'''
** Secondary buds always develop on the same side of the stem: '''helicoid cyme''' or '''bostryx'''
*** The successive pedicels are aligned on the same plane: '''drepanium'''
** Secondary buds develop alternately on the stem : '''scorpioid cyme'''
*** The successive pedicels are arranged in a sort of spiral: '''cincinnus''' (characteristic of the [[Boraginaceae]] and [[Commelinaceae]])
*** The successive pedicels follow a zig-zag path on the same plane: '''rhipidium''' (many [[Iridaceae]])
* Two secondary axes: '''dichasial cyme'''
** Secondary axis still dichasial: '''dichasium''' (characteristic of [[Caryophyllaceae]])
** Secondary axis monochasia: '''double scorpioid cyme''' or '''double helicoid cyme'''
* More than two secondary axes: '''pleiochasium'''

<gallery>
File:Monochasium(inflorescence).svg|Simple dichasium
File:Doppelwickel (inflorescence).svg|Double cyme
File:Doppelschraubel (inflorescence).svg|Double cyme
File:Schroef (bloeiwijze).jpg|Bostryx (lateral and top view)
File:Saint John's wort flowers.jpg|''[[Hypericum perforatum]]'' (bostryx)
File:Sikkel (bloeiwijze).jpg|Drepanium (lateral and top view)
File:Gladiolus imbricatus a1.jpg|''[[Gladiolus imbricatus]]'' (drepanium)
File:Schicht.jpg|Cincinnus (lateral and top view)
File:Symphytum officinale 02.jpg|''[[Symphytum officinale]]'' (cincinnus)
File:Waaier (bloeiwijze).jpg|Rhipidium (lateral and top view)
File:Canna Endeavour 01.jpg|''[[Canna (plant)|Canna]] sp.'' (rhipidium)
File:Dichasium (inflorescence).svg|Dichasium
File:Dichasium (top view) (inflorescence).svg|Dichasium, top view
File:2006-10-22Silene dioica07.jpg|''[[Silene dioica]]'' (dichasium)
</gallery>

A cyme can also be so compressed that it looks like an umbel. Strictly speaking this kind of inflorescence could be called '''umbelliform cyme''', although it is normally called simply 'umbel'.

Another kind of definite simple inflorescence is the raceme-like cyme or '''botryoid'''; that is as a raceme with a terminal flower and is usually improperly called 'raceme'.

<gallery>
Image:Inflorescences Umbel Kwiatostan Baldach.svg|Umbelliform cyme
Image:Fiore di geranio.JPG|''[[Pelargonium zonale]]'' (umbelliform cyme)
Image:Botryoid (inflorescence).svg|Botryoid
Image:Berberis vernae MS 4426.jpg|''Berberis vernae'' (botryoid)
</gallery>

A reduced raceme or cyme that grows in the [[axil]] of a bract is called a '''fascicle'''. A '''verticillaster''' is a fascicle with the structure of a dichasium; it is common among the [[Lamiaceae]]. Many verticillasters with reduced bracts can form a spicate (spike-like) inflorescence that is commonly called a '''spike'''.

<gallery>
Image:Gentiana lutea1.JPG|''[[Gentiana lutea]]'' (fascicles)
Image:Lamium orvala3.jpg|''[[Lamium orvala]]'' (verticillaster)
Image:Mentha longifolia 2005.08.02 09.53.56.jpg|''[[Mentha longifolia]]'' ('spike')
</gallery>

===Compound inflorescences===
Simple inflorescences are the basis for compound inflorescences or '''synflorescences'''. The single flowers are there replaced by a simple inflorescence, which can be both a racemose or a cymose one. Compound inflorescences are composed of branched stems and can involve complicated arrangements that are difficult to trace back to the main branch.

A kind of compound inflorescence is the '''double inflorescence''', in which the basic structure is repeated in the place of single florets. For example, a double raceme is a raceme in which the single flowers are replaced by other simple racemes; the same structure can be repeated to form triple or more complex structures.

Compound raceme inflorescences can either end with a final raceme ('''homoeothetic'''), or not ('''heterothetic'''). A compound raceme is often called a '''panicle'''. This definition is very different from that given by [[Focko Weberling|Weberling]].

Compound umbels are umbels in which the single flowers are replaced by many smaller umbels called '''umbellets'''. The stem attaching the side umbellets to the main stem is called a '''ray'''.

<gallery>
Image:Doppeltraube_(inflorescence).svg|Homeothetic compound raceme
Image:Melilotus officinalis01.jpg|''[[Melilotus officinalis]]'' (homoeothetic compound raceme)
Image:Doppeltraube_2_(inflorescence).svg|Heterothetic compound raceme
Image:Hebe albicans.jpg|''[[Veronica albicans]]'' (heterothetic compound raceme)
Image:Inflorescences Muktispike Kwiatostan KłosZłożony.svg|Compound spike
Image:Lolium multiflorum detail.jpeg|''[[Lolium temulentum]]'' (compound spike)
Image:Doppelkoepfchen_(inflorescence).svg|Compound capitulum
Image:Echinops Ain France.jpg|''[[Echinops ritro]]'' (compound capitulum)
Image:Inflorescences Umbel Kwiatostan BaldachZłożony.svg|Compound (double) umbel
Image:Laserpitium latifolium2.jpg|''[[Laserpitium latifolium]]'' (double umbel)
Image:Dreifachdolde_(inflorescence).svg|Compound (triple) umbel
</gallery>

The most common kind of definite compound inflorescence is the '''panicle''' (of Webeling, or 'panicle-like cyme'). A panicle is a definite inflorescence that is increasingly more strongly and irregularly branched from the top to the bottom and where each branching has a terminal flower.

The so-called cymose '''corymb''' is similar to a racemose corymb but has a panicle-like structure. Another type of panicle is the '''anthela'''. An anthela is a cymose corymb with the lateral flowers higher than the central ones.

<gallery>
Image:Inflorescences Panicle Kwiatostan Wiecha.svg|[[Panicle]]
Image:Vigne inflorescence 2.jpg|''[[Vitis vinifera]]'' (panicle)
Image:Schirmrispe (inflorescence).svg|Cymose [[corymb]]
Image:Sambucus nigra 003.jpg|''[[Sambucus nigra]]'' (cymose corymb)
Image:Spirre (inflorescence).svg|Anthela
Image:Juncus inflexus.jpeg|''[[Juncus inflexus]]'' (anthela)
</gallery>

A raceme in which the single flowers are replaced by cymes is called a (indefinite) '''thyrse'''. The secondary cymes can be of any of the different types of dichasia and monochasia. A botryoid in which the single flowers are replaced by cymes is a '''definite thyrse''' or '''thyrsoid'''. Thyrses are often confusingly called '''panicles'''.

<gallery>
Homöokladische Thyrse (inflorescence).svg|Thyrse
Aesculus hippocastanum flori.jpg|''[[Aesculus hippocastanum]]''
Dichasialer zymus (inflorescence).svg|Thyrsoid
Syringa11.jpg|''[[Syringa vulgaris]]''
</gallery>

Other combinations are possible. For example, heads or umbels may be arranged in a corymb or a panicle.

<gallery>
Achillea (yarrow) - 16.JPG|''[[Achillea]]'' sp. (heads in a corymb)
Starr 010419-0021 Hedera helix.jpg|''[[Hedera helix]]'' (umbels in a panicle)
</gallery>

===Other===
The family [[Asteraceae]] is characterised by a highly specialised head technically called a '''[[calathid]]''' (but usually referred to as 'capitulum' or 'head'). The family [[Poaceae]] has a peculiar inflorescence of small spikes ('''[[spikelet]]s''') organised in panicles or spikes that are usually simply and improperly referred to as '''spike''' and '''panicle'''. The genus ''[[Ficus]]'' ([[Moraceae]]) has an inflorescence called a hypanthodium, which bears numerous flowers on the inside of a convex or involuted compound receptacle.<ref>Simpson, M. G. 2010. ''Plant Systematics'' Burlington: Academic Press. p. 509</ref> The genus ''[[Euphorbia]]'' has '''[[cyathium|cyathia]]''' (sing. ''cyathium''), usually organised in umbels.

<gallery>
Chamomile@original size.jpg|''[[Matricaria chamomilla]]'' (calathid)
Wheat close-up.JPG|''[[Triticum aestivum]]'' (compound spikes, "spikes")
Lemont rice.jpg|''[[Oryza sativa]]'' (spikes in a panicle, "panicle")
Some figs.jpg|''[[Ficus carica]]'' (hypanthodium)
Euphorbia tridentata ies.jpg|''[[Euphorbia tridentata]]'' (cyathium)
Euphorbia cyparissias 02 bgiu.jpg|''[[Euphorbia cyparissias]]'' (cyathia in an umbel)
Coleus inflorescence.JPG|''[[Coleus]]'' (false spike)
</gallery>

Some species have inflorescences reduced to [[Pseudanthium|composite flowers or pseudanthia]], in which case it is difficult to differentiate between inflorescences and single flowers.<ref name=":9">{{Cite journal|last1=Tucker|first1=Shirley C.|last2=Grimes|first2=James|date=1999-10-01|title=The inflorescence: Introduction|journal=The Botanical Review|language=en|volume=65|issue=4|pages=303–316|doi=10.1007/BF02857752|bibcode=1999BotRv..65..303T |s2cid=29599096|issn=0006-8101}}</ref>