Raceme
Encyclopedia
A raceme is a type of inflorescence
that is unbranched and indeterminate
and bears pedicellate flower
s — flowers having short floral stalks called pedicel
s — along the axis. In botany
, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne towards the base and new flowers are produced as the shoot grows. A plant that flowers on a showy raceme may have this reflected in its scientific name, e.g. Cimicifuga racemosa
.
A spike is a type of raceme in which individual flowers are sessile (that is, lack pedicels). The term spikelet can refer to a small spike, although it is primarily used to refer to the ultimate flower cluster unit in the grasses (Family Poaceae
), in which case the stalk supporting the cluster becomes the pedicel. A true spikelet comprises one or more florets enclosed by two glumes (bract
s), and is not a raceme.
A spadix
is a form of spike in which the florets are densely crowded along the axis. They are enclosed or accompanied by a highly specialized bract
called a spathe and are a characteristic of the Araceae
family.
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
that is unbranched and indeterminate
Indeterminate growth
In biology and especially botany, indeterminate growth refers to growth that is not terminated in contrast to determinate growth that stops once a genetically pre-determined structure has completely formed. Thus, a plant that grows and produces flowers and fruit until killed by frost or some other...
and bears pedicellate flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s — flowers having short floral stalks called pedicel
Pedicel (botany)
A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....
s — along the axis. In botany
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne towards the base and new flowers are produced as the shoot grows. A plant that flowers on a showy raceme may have this reflected in its scientific name, e.g. Cimicifuga racemosa
Cimicifuga racemosa
Actaea racemosa is a plant of the buttercup family . It is native to eastern North America from the extreme south of Ontario to central Georgia, and west to Missouri and Arkansas...
.
A spike is a type of raceme in which individual flowers are sessile (that is, lack pedicels). The term spikelet can refer to a small spike, although it is primarily used to refer to the ultimate flower cluster unit in the grasses (Family Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
), in which case the stalk supporting the cluster becomes the pedicel. A true spikelet comprises one or more florets enclosed by two glumes (bract
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 often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
s), and is not a raceme.
A spadix
Spadix
In botany, a spadix is a type of spike inflorescence having small flowers borne on a fleshy stem. Spadix are typical of the Family Araceae known as arums or aroids...
is a form of spike in which the florets are densely crowded along the axis. They are enclosed or accompanied by a highly specialized bract
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 often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...
called a spathe and are a characteristic of the Araceae
Araceae
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 known as the Arum family, members are often colloquially...
family.