2 Brassica oleracea var. acephala

Acephala group of Brassica oleracea cultivars.

These are forms that resemble wild Brassica oleracea in that they do not develop a head.
They come in many flat or curly leaf types and include the cultivars:

Brassica oleracea var. sabellica, edible kale which comes in curly or flatter leaf forms.
The curly ones have deeply dissected blades with a frilly edge.

Brassica oleracea var. acephala is ornamental kale.
These plants, grown as annuals also come in crinkly and flatter leaf froms.
The crinkly form is known as Ornamental kale and the flatter leaf as Ornamental cabbage.
Kales can grow to 45 or 60 cm.
Leaf colours include green, reddish-purple, deep purple and pink as well as cream and white.

There are other cultivars with ‘kale’ in their name in other groups.