THAPSIA, the DEADLY CARROT, in botany: A genus of plants belonging to the class of pentandria, and order of digynia; and in the natural system ranging under the 45th order, umbellata. The fruit is oblong and gilt with a membrane. There are five species; the villosa, foetida, asclepium, garganica, and trifoliata. The roots of the foetida were formerly ordered in medicine, but are now entirely disused; a small dose operating with extreme violence both upwards and downwards.