Brassica rapa L.

Global description
Brassica rapa is an annual or biennial herbaceous erect plant  reaching 1.20 m high, with a taproot containing reserves. The leaves are alternate andsimple; the lower leaves are large, lyrate, cut into deep lobes, bristling with stiff hairs, and the upper leaves are small, whole, clasping, glabrous. The flowers are stalked, yellow in colour, with petals spread in cross, and spreading sepals. They are grouped in dense terminal inflorescence that extends to fructification. The fruit is a long cylindrical pod elongated with a point. Seeds are globose with finely roughened surface.

 
Cotyledons
The cotyledons are stalked, kidney-shaped, smooth and glabrous.
 
First leaves
The first leaves are oblong with irregularly wavy margin.
 
General habit
Annual or biennial herbaceous plant, erect, measuring 40 cm to 1.20 m high.
 
Underground system
The main taproot contains a lot of reserves and is napiform.
 
Stem
The stem is strong. With a cylindrical cross section, glabrous and smooth, except for a few isolated hairs.
 
Leaf
The leaves are alternate and simple. The lower leaves, usually sessile, measure up to 30 cm long. They are cut into deep and lyrate lobes, with an obtuseterminal lobe. They are green in color and are bristling with stiff hairs. Their margin is sinuate or dentate, frequently ciliated. The ventral side is dotted with tiny tubers of fine bristles, especially on the ribs. The upper leaves are oblong-lanceolate (less than 10 cm in length), with a cordiform base, enveloping the stem, whole, and with a sinuate or serrated margin. Their surface is glaucous and glabrous.
 
Inflorescence
Flowers grow in a continuous manner on a terminal inflorescence on which they are grouped during flowering. The inflorescence elongates during fructification.
 
Flower
The flowers are golden yellow in colour, and long stalked. The calyx is formed by four oblong-elliptical sepals of 5 to 8 mm long, which are slightly spread. The 4 yellow petals are obovate (7 to 12 mm long and 5-6 mm wide) and are spread horizontally and arranged crosswise. The 6 stamens are divided into two groups: two lateral and 4 median. The elongated ovary contains 20 to 30 eggs. It measures 2 mm long and carries a two-lobed stigma.
 
Fruit
The fruit is a cylindrical ascending pod with a long stalk, 5 to 6 cm long, and ending with a point of 1 to 2.5 cm. It opens at maturity by 2 dehiscent valves at the base.
 
Seed
The seed is globular, slightly compressed, 1 to 3 mm in diameter, finely rough surface.
 

Origin

Brassica rapa is native to the Mediterranean basin.

Worldwide distribution

This species is now widely distributed throughout North, Central and South America, the Caribbean, Europe, East Africa, India, Asia and Oceania.

https://www.gbif.org/species/7903057