Rapistrum
Encyclopedia
Rapistrum is a genus
belonging to the brassicaceae
family with a distinctive cross like arrangement of its petal
s. Species
of Rapistrum are annual
to perennials
(Lifespan from 1 to 2 or more years). The yellow petals are accompanied by sepal
s that stand vertically at near right angles (erecto-patent). Leaf shape
and arrangement varies from rough toothed (dentate
) to a configuration of opposingly lobed pairs along the plant stalk, pinnately lobed
.
comprising 2 segments.
a) The distal (upper division)
The part of the fruit farthest away from the point of attachment. The distal is endowed with a ribbed spheroid base (globose) that tapers to form a narrowed projection. It holds a single seed.
b) The proximal (lower division)
The part of the fruit nearest to the point of attachment. Possesses a more uniform narrower shape compared to the distal above, giving the fruit a waist. It holds a maximum of three seeds, more commonly none or one.
The fruit
varies from species
to species. The distal of R. rugosum
is strongly ribbed and narrows to form a beak whereas R. perenne is comparatively less wrinkled and ends with a style that stubbornly resists detachment, 'a persistent style'.
When ripe the distal breaks away in an across-wise fashion, breaking transversely.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
belonging to the brassicaceae
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
family with a distinctive cross like arrangement of its petal
Petal
Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...
s. Species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of Rapistrum are annual
Annual plant
An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...
to perennials
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
(Lifespan from 1 to 2 or more years). The yellow petals are accompanied by sepal
Sepal
A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...
s that stand vertically at near right angles (erecto-patent). Leaf shape
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
and arrangement varies from rough toothed (dentate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
) to a configuration of opposingly lobed pairs along the plant stalk, pinnately lobed
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
.
Fruit
The Rapistrum genus has a characteristic fruitFruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
comprising 2 segments.
a) The distal (upper division)
The part of the fruit farthest away from the point of attachment. The distal is endowed with a ribbed spheroid base (globose) that tapers to form a narrowed projection. It holds a single seed.
b) The proximal (lower division)
The part of the fruit nearest to the point of attachment. Possesses a more uniform narrower shape compared to the distal above, giving the fruit a waist. It holds a maximum of three seeds, more commonly none or one.
The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
varies from species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
to species. The distal of R. rugosum
Rapistrum rugosum
Rapistrum rugosum is a species of flowering plant in the mustard family known by the common names annual bastard cabbage, common giant mustard or turnipweed. It is native to Eurasia and parts of Africa, and it is present throughout the world as an introduced species and a common weed. It is an...
is strongly ribbed and narrows to form a beak whereas R. perenne is comparatively less wrinkled and ends with a style that stubbornly resists detachment, 'a persistent style'.
When ripe the distal breaks away in an across-wise fashion, breaking transversely.