This is the plant, or one of the plants, which is offered as Lycoris aurea in the mass distribution catalogs. It's one of the less cold hardy species of the genus Lycoris: the foliage will be destroyed or badly damaged in a bad winter. In those cases, the bulbs survive in a weakened condition, and after several iterations of the winter killing of the foliage the plants disappear. At least that has been my experience with them. Those of you who know this plant only from the experience of recent years might be unpleasantly surprised to see what happens when we once again have a real winter.
It grows well in a cold frame, and now that I've seen it in bloom I'll be a little more accepting of the mound of leaves it produces. It's less than two feet high, so this is not one of the taller species. The foliage of this plant is wider than that of the other commonly grown lycorises. I've grown two forms here: one with bright green leaves (the one seen in the image above) and another with darker, bluish-green leaves.
The name I've used here for it, Lycoris aurea mercatorum, is not one you're likely to find in any reference book. "Mercatorum" means "of the merchants", and is a designation which was used by authors in times past to indicate that the plant in question does not appear to be the rightful claimant to the name.
Is this Lycoris traubii? I don't know. I welcome suggestions.