This is the smallest Justicia that grows in my garden. It has had many other names over the years, having been classified at different times as belonging to the genera Peristrophe and Porphyrocoma, for example. Hailing from Brazil, it grows to around 20 cm and in England is used as a basket plant. It has attractive silver-veined leaves and chubby spikes of burgundy-bracts enclosing mauve flowers, from late summer to spring.
I like to grow it amongst silver-leaved rhizomatous Begonia or velvety silver groundcover Plectranthus 'Nicoletta' in a shaded spot, to echo its foliage markings. It also looks pretty nearby coleus with pinkish or burgundy leaf markings, It self-seeds a bit, but it is such a compact and pretty plant, that I don't mind this at all, and all my surplus seedlings have found homes with other gardeners. It will grow in any type of shade. I have seen it called colloquially 'rose pine'.