Phalaenopsis - Feburary 2022 - Sarah Stierch 02

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

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, 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 mai ...

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 (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

'' Brassica''), radish (genus '' Raphanus''), and orchid (genus '' Phalaenopsis'') plants.

Definition

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

bearing pedicellate

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s (flowers having short floral stalks called ''

pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branch ...

'') along its axis. In

botany Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

, 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 A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

'' Actaea racemosa''. A compound raceme, also called a

panicle In botany, 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 p ...

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

'' Brassica'') 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''). A

spikelet A spikelet, in botany, describes the typical arrangement of the inflorescences 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 sp ...

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 wikt:sedge, sedges. The family (biology), family is large; botanists have species description, described some 5,500 known species in about 90 ...

), 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 grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flow ...

s (sterile

bract In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...

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

Oryza sativa ''Oryza sativa'', having the common name Asian cultivated rice, is the much more common of the two rice species cultivated as a cereal, the other species being ''Oryza glaberrima, O. glaberrima'', African rice. It was History of rice cultivation ...

'') and wheat (genus '' Triticum''), 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 Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...

, nd birch". 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 '' spathes''. 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). Also ...

, for example jack-in-the-pulpit (species '' Arisaema triphyllum'') and wild calla (genus '' Calla'').

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'', 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. Orchids are cosmopolitan plants that are found in almost every habitat on Eart ...

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

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

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