Water Caltrops

Tribulus aquaticus, tribulus marinus. Called water nuts, and water chestnuts.

There are two caltrops; the first has a creeping and jointed root, sending forth tufts at each joint, from which joints arise long, flat, slender-knotted stalks, to the top of the water, divided into many branches, each having two leaves on both sides, two inches long, and half an inch broad, almost transparent, they look as if they were torn; the flowers are long, thick and whitish, set like a bunch of grapes, succeeded for the most part by sharp-pointed grains altogether, containing a small white kernel in them.

The second differs little except it delights in clearer water. Its stalks are round; its leaves are more pointed. They grow in the water, as their name implies.

Made into a poultice, they are good for inflammations, swellings, cankers, sore mouths and throats, being washed with the decoction. They cleanse and strengthen the neck and throat, and reduce the swellings of the same. It is a good remedy for the king's evil; for the stone and gravel, especially the nuts, being dried.