A raceme ( or ) or racemoid is an unbranched, indeterminate type of

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the shoot grows in height, with no predetermined growth limit. Examples of racemes occur on mustard (

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

Brassica ''Brassica'' () is a genus of plants in the cabbage and mustard family ( Brassicaceae). The members of the genus are informally known as cruciferous vegetables, cabbages, or mustard plants. Crops from this genus are sometimes called ''cole c ...

'') and radish (genus '' Raphanus'') plants.

Definition

A ''raceme'' or ''racemoid'' is an unbranched, indeterminate type of

bearing pedicellate

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s (flowers having short floral stalks called ''

pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as ''pedicellate''. Description Pedicel refers to a structure connecting a single flower to its inflorescence. In the absenc ...

'') along its axis. 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 Ancient Greek w ...

, an ''axis'' means a shoot, in this case one bearing the flowers. In indeterminate inflorescence-like racemes, the oldest flowers grow close to the base and new flowers are produced as the shoot grows in height, with no predetermined growth limit. A plant that flowers on a showy raceme may have this reflected in its scientific name, e.g. the

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

Cimicifuga racemosa ''Actaea racemosa'', the black cohosh, black bugbane, black snakeroot, rattle-top, or fairy candle ( syn. ''Cimicifuga racemosa''), is a species of flowering plant of the family Ranunculaceae. It is native to eastern North America from the extrem ...

''. A compound raceme, also called a

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

, has a branching main axis. Examples of racemes occur on mustard (

'') and radish (genus '' Raphanus'') plants.

Spike

A spike is an unbranched, indeterminate inflorescence, similar to a raceme, but bearing sessile flowers (sessile flowers are attached directly, without stalks). Examples occur on Malabar nut ('' Justicia adhatoda'') and chaff flowers (genus ''

Achyranthes ''Achyranthes'' is a genus of medicinal and ornamental plants in the amaranth family, Amaranthaceae. Chaff flower is a common name for plants in this genus. Species include: * '' Achyranthes ancistrophora'' C.C.Towns. * '' Achyranthes arboresce ...

''). A

spikelet A spikelet, in botany, describes the typical arrangement of the flowers of grasses, sedges and some other Monocots. Each spikelet has one or more florets. The spikelets are further grouped into panicles or spikes. The part of the spikelet that ...

can refer to a small spike, although it primarily refers to the ultimate flower cluster unit in grasses ( family Poaceae) and sedges (family

Cyperaceae The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...

), in which case the stalk supporting the cluster becomes the pedicel. A true spikelet comprises one or more florets enclosed by two

glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and ...

s (sterile

bract 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 o ...

s), with flowers and glumes arranged in two opposite rows along the spikelet. Examples occur on rice (species '' Oryza sativa'') and wheat (genus ''

Triticum Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeological ...

''), both grasses.

Catkin

An ament or catkin is very similar to a spike or raceme "but with subtending bracts so conspicuous as to conceal the flowers until pollination, as in the pussy–willow, alder, nd

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' cont ...

...". These are sometimes called ''amentaceous plants''.

Spadix

A spadix is a form of spike in which the florets are densely crowded along a fleshy axis and enclosed by one or more large, brightly–colored

s called ''

spathe 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 ...

s''. Usually the female flowers grow at the base, and male flowers grow above. They are a characteristic of the family

Araceae The Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe (or leaf-like bract). A ...

, for example jack–in–the–pulpit (species ''

Arisaema triphyllum ''Arisaema triphyllum'', the jack-in-the-pulpit, bog onion, brown dragon or Indian turnip, is a herbaceous perennial plant growing from a corm. It is a highly variable species typically growing in height with three-part leaves and flowers cont ...

'') and wild calla (genus ''

Calla ''Calla'' (bog arum, marsh calla, wild calla, squaw claw, and water-arumDickinson, T.; Metsger, D.; Bull, J.; & Dickinson, R. (2004) ROM Field Guide to Wildflowers of Ontario. Toronto:Royal Ontario Museum, p. 62.) is a genus of flowering plant ...

'').

Examples

File:Traube (inflorescence).svg, File:Inflorescences Spike Kwiatostan Kłos.svg, File:Kätzchen (inflorescence).svg, File:Kolben (inflorescence).svg, File:Spathoglottis flwrs reduced.jpg, The inflorescence of ''

Spathoglottis plicata ''Spathoglottis plicata'', commonly known as the Philippine ground orchid, or large purple orchid is an evergreen, terrestrial plant with crowded pseudobulbs, three or four large, pleated leaves and up to forty resupinate, pink to purple flow ...

'', a terrestrial

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of floweri ...

, is a typical raceme. File:Backlit xeronema flower raceme.jpg, Tightly packed raceme of '' Xeronema callistemon'', with prominent red

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the fila ...

s File:Pycreus.jpg, Every radiating unit in this inflorescence of a ''

Cyperus ''Cyperus'' is a large genus of about 700 species of sedges, distributed throughout all continents in both tropical and temperate regions. Description They are annual or perennial plants, mostly aquatic and growing in still or slow-moving ...

'' sedge is a spikelet composed of small flowers (florets) arranged in two ranks.

Etymology

From classical Latin, a ''racemus'' is a cluster of grapes.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

References

{{Authority control Flowers Plant morphology sv:Blomställning#Typer av blomställningar