The daffodil genus
Narcissus is built around one structure that no close relative has, it is named after a drug rather than a myth, and a Welsh hill farm crop of it is grown for medicine rather than for flowers.
roughly 50 wild species and many thousands of cultivars
Western Europe and North Africa, centered on Spain and Portugal
Everything in this guide that belongs to Narcissus
Look at any member of this genus and the flower divides cleanly into two parts. There are six spreading segments at the back, and then a separate structure standing forward from the middle of them: the trumpet, cup or eye, depending on how long it is.
That forward part is called the corona, and it is not made of petals. It grows out of the flower between the tepals and the stamens, as an extra ring of tissue that no other genus in this family produces, and it can be longer than the tepals, a shallow saucer, a flat rim or almost nothing at all. The stamens sit inside it, hidden.
Nobody is entirely settled on what it is derived from, and it has been argued for a century. What is not in dispute is the function: it is a landing guide and a nectar tube in one, and it does the work that a fused corolla does in other flowers, arrived at from different parts.
With tens of thousands of registered cultivars, this genus needs a working classification more than most, and the one everybody uses is built almost entirely on that corona. The divisions are defined by how long the corona is relative to the tepals and by how many flowers a stem carries.
Corona as long as the tepals or longer and one flower to a stem: that is the trumpet daffodil everybody pictures. Corona more than a third the length but not the full length: large cupped. Less than a third: small cupped. Then the divisions named after the wild species they descend from, several flowers to a stem with a short cup and a heavy scent, or swept back tepals, or narrow rush like leaves, and a division for the white one with a tiny red rimmed eye.
This is not botanical bookkeeping. Ordering from a grower means using these terms, and they tell you what you are getting far more reliably than a variety name does.
Everybody knows the myth of the young man who fell in love with his own reflection, and it is a good story, but it is probably not where the name comes from. The likelier root is the Greek word for numbness, the same one behind narcotic, and it refers to what the plant does rather than to who it was named after.
Every part of these plants, and the bulb most of all, carries a group of alkaloids that are seriously unpleasant to eat. The consequence that actually recurs is a supermarket one: the bulbs look enough like small onions or shallots that people cook them by mistake, and health authorities in Britain have repeatedly warned retailers not to display them near produce after outbreaks of exactly that.
The same chemistry is why grazing animals leave the plants alone, why they naturalize so successfully in fields, and why a stand of them in a meadow widens year on year while everything around it gets eaten.
One of those alkaloids turned out to be worth extracting. Galantamine is used in the treatment of Alzheimer's disease, it was originally isolated from plants in this family, and synthesizing it economically is difficult enough that growing it is competitive.
The odd part is where. The compound is produced in higher concentrations when the plant is stressed by cold and altitude, so daffodils for extraction are grown high on Welsh hill farms, on ground that is marginal for almost anything else, on land that had been sheep pasture. The flowers are irrelevant to the crop and the fields are not picked.
It is a genuinely unusual thing to be able to say about a supermarket spring flower: that the same plant, grown deliberately badly in a cold place, is a pharmaceutical crop.