Iris unguicularis, the Algerian iris, began to bloom last week; the flower you see in the image above is the second to appear this season. This species has the potential to bloom from November right through April. The plant shown above grows in a cold frame; another one grows nearby outside the frame.
The flower buds are very sensitive to freezing in my experience, so the plants get covered on cold nights. When they successfully bloom during the winter they are the largest true flowers to be seen in the garden.
The related irises known as Iris cretensis and I. lazica will follow later; in fact, I see flower buds developing on I. cretensis now.