Form
Acephala Group
Collard Greens, Kales
This biennual or perennial plant has unbranched stems with loose rosettes of thick and slightly bitter edible oblong dark green leaves that do not make solid heads (cabbage-like). It is commonly cultivated in southern United States, Brazil, Portugal, Africa and Europe. It has been cultivated for over 2000 years and the leaves are normally collected before maturity. The flavour depends on the cultivar and is a good source of vitamin C and fibre.

Alboglabra Group
Chinese broccoli, Kai-lan
This leaf vegetable is an annual to perennial that grows to 1m (3 ft) tall with a thick stem and has thick glaucous (blue-green) elliptical lower leaves that are up to 255 mm (10 in) long and long oblong upper leaves.  It produces white flowers in a dense head (similar to broccoli) and is the leaf vegetable that is widely used in Chinese cuisine.

Botrytis Group
Cauliflower, Broccoflower 
This annual has a short stem and produces a dense inflorescence of modified flowers that is over topped by the foliage. 

Cauliflower is an annual vegetable that is grown from seed and produces an edible dense white inflorescence meristem (head). There are 4-major groups of cauliflowers that include;
1) Italian
This ancestral form has given rise to biannual or annual types that include Romanesco varieties that are white, green, purple, round and yellow.

2) North-west European biennial
This variety was developed in France in the 19th century and is grown in Europe for winter and early spring harvest and includes cultivars such as 'Roscoff' and 'Angers'

3) Northern European annuals
this form was developed in Germany during the 18th century and is grown in Europe and North America for summer or autumn harvest. It includes cultivars such as 'Erfurt' and Snowball'.

4) Asian
This form was developed in India during the 19th century and is grown in China and India in tropical climates. It includes varieties such as 'Early Patna' and 'Early Benaras'.

Note:
Cauliflowers are available in a range of colours that include white (most common), orange (as a high level of vitamin A), green (Broccoflower) and purple (as a high presence of antioxidants).

Broccoflower is distinguished by 2-edible plants with a light green immature flower heads (inflorescence meristem) and referred to as a cultivar of cauliflower. The green cauliflower is similar to white cauliflower but is lime green in colour and there are several cultivars available such as 'Green Ball'.

Capitata Group
Cabbage Head
This leafy biennial is normally grown at an annual vegetable for its dense terminal head of leaves and has been cultivated in Europe since 1000 BC. The leaves are puckered to blistered or smooth and can be green, purple and white in colour. Cabbage heads range in weight from 0.5 to 4 kg and are normally picked during the first year unless seed is required. Modern forms have been bred for frost hardiness, rapid growth, pests and disease resistance and storage ability.

Gemmifera Group
Brussels Sprout
This annual vegetable has an erect stem to 1 m (3 ft) tall that is covered in small compact edible buds and has a terminal leafy flower head. The buds are up to 40 mm () in diameter and appear as miniature cabbages.  The current form of Brussels sprouts appeared in the early 13th century but may have been cultivated prior to this during the Roman period. Main production regions include Continental Europe, the UK and California in North America.

Gongylodes Group
Turnips, German turnip 
This low stout biennial as has an enlarged stem that produces an edible tuber just above ground level with radiating elliptical leaves that are up to 255 mm (10 in) long and have a long pale green petiole. The tuber is up to 50 mm (2 in) in diameter with 2-distinct fibrous layers and tends to be woody with a sweet taste. There are several varieties available that include, 'White Vienna', ‘Purple Vienna', 'Gigante', 'White Danube' and 'Purple Danube'.

Italica Group
Broccoli
This annual is similar to the Botrytis group but has short branched stems that produce a dense flower head that is not   condensed into a solid head (inflorescence). The green flower head is arranged in a tree-like structure with thick edible branches and is accompanied with edible oblong grey green leaves. It is thought to have been cultivated since the early 6th century in the northern Mediterranean region and now there are three commonly grown forms.
1) Calabrese broccoli
This cool season annual is the most common form and produces large green head with thick stalks up to 200 mm (7¾ in) in diameter.
2) Sprouting broccoli
This annual produces large amounts of dense heads on slender stems.
3) Purple broccoli
This form produces cauliflower like flower heads tiny flower buds that may have a purple tint.  It is commonly found in southern Italy, Spain and the United Kingdom.

Cultivars
Osaka series
These ornamental cabbages are grown for their colourful foliage. There are several cultivars available with the wavy brute green outer leaves and a compact centre that is white, pink or red.  They are mass planted for bedding displays or grown as individuals in patio pots and planter boxes.

'Tokyo'
This cultivar forms a compact rounded habit up to 250 mm (10 in) tall with blue green outer leaves and soft pink or red and white centres.  It is grown as an ornamental in small gardens or used along borders for colour contrast.