Nasturtium officinale

Nasturium offincinale

(notice the seed pods)

Watercress is a traditional food in Britain, where the herb was originally found in the wild, but became so popular that they have to cultivate it now to keep up with the demand. It is a member of the mustard family, and can be quite spicy on its own, but goes well with other food.

To find watercress, you must find clean, slow-moving water. Often that means a natural spring, but it can also be found growing in small rivulets. The biggest clue from a distance will be the white flowers with four petals. Upon closer examination you should find the alternate compound leaves. (Compound leaves look like a branch of smaller leaflets, but botanists consider it a single leaf.) Finally, find the sea pods, which should be growing underneath the flowers, unless it is very early in the spring. Technically, seed pods in the mustard are called "siliques". But the important thing is that they are about a centimeter long and slightly curved. You've found your watercress. Remember to make sure your water is clean. Usually that means no farm animals grazing upstream.

When I eat watercress plain, I can only enjoy a single stem's worth before it gets rather too burny-hot. However it combines very well with other food and in salads. I tried it the British way, on a sandwich with butter and hard-boiled egg, and I was piling more and more watercress on, because it tastes very good, and the egg and bread remove most of the hot spiciness.

Watercress has a lot of vitamins and some trace minerals. Compared to the same amount of spinach it has about twice as much vitamin C, a quarter the amount of vitamin A, and about half as much vitamin K. It has similar amounts of calcium, about half as much potassium, and about a quarter the magnesium and manganese as spinach.

Note that the ivory-tower botanists are still bickering over what to call watercress in Latin. Many call it Rorippa nasturtium-aquaticum instead of Nasturtium officinale. It has no relation to the garden flowers called nasturiums. Recent DNA studies are placing it closer to the Cardamine genus than the Rorippa genus, to which I say, "duh!"

I also noticed that there is something called "fool's watercress". This is a member of the carrot family. The flowers have five petals (not four, like watercress), and like all the carrot family, the flowers grow in umbels (all the flower stems come from a single point). In the mustard, including with watercress, the flowers grow in racemes, where each flower branches off individually from a central stalk. Fool's watercress is also edible, but some other members of the carrot family are poisonous.