A semi-tropical, soft-leaved bushy perennial, Iresine herbstii (ht 60cm) belongs to the Amaranthaceae familt of plants and comes from Brazil. It is often called the beefsteak plant, with the most commonly seen being the reddish form, 'Brilliantissima', which has rich crimson-veined dark purplish leaves, which are heart-shaped. It has a fairly upright form. There seems to be a slightly different cultivar, which is more sprawling and with indented, kidney-shaped leaves and a more open, sprawling habit, apparently called 'Verschaffeltii'.
There are a couple of forms with mid-green leaves with yellow veining. One has pointed leaves similar in shape to 'Brilliantissima', and with pinkish stems and petioles, which seems to be known as 'Formosana'. The other has notched leaves shaped like 'Verschaffeltii' and often develops leaves that are reddish in patches or even all over; this cultivar is called 'Aureoreticulata'. Years ago, I acquired a cutting of a plain form of Iresine which has quite large leaves of a deep purplish-brown, which grows to 1.5 m (shown in the photo below). It is a very useful foliage plant, mixing effortlessly with almost any colour flower. I have yet to find out its cultivar name. The cultivar 'Wallisii' also has plain purplish-brown leaves but they are smaller and more rounded than the other cultivars, and strangely twisted on their stalks. Iresine plants are very adaptable and will grow in sun or shade - the colouration of the leaves is more pronounced in a sunny place. They will grow in quite ordinary soil and don't need a lot of water. I cut mine back very hard around the beginning of September.
The leaves lend themselves to many colour echoes in the garden, by pairing a flower of the same hue to the veins of the beefsteak plant, or in the case of the dark purplish-brown variety, matching the foliage colour to another plant's dark stems or flower bracts. I use many different flowers for these combinations as I have a number of Iresine growing in my garden - Canna and Salvia are two which I often plant nearby to Iresine. All Iresine are frost tender. The flowers are insignificant. They are easily propagated from cuttings and will even take root in a glass of water!
Note: Some authorities call this plant Iresine diffusa now; Iresine herbstii is, however, still a valid name. I am unable to clarify the correct name as yet.