A toxic plant found on M-113, at first blamed for the death of Crewman Darnell in The Man Trap before the real killer proves to be a salt-draining creature.
The Borgia plant is a poisonous species of vegetation growing on the desert world M-113. It appears in The Man Trap, the first episode of The Original Series to be broadcast, set in 2266.
When Crewman Darnell is found dead outside the ruins where the archaeologist Robert Crater works, a piece of the plant is in his mouth, and Nancy Crater says she saw him eating it. Spock reports that the Borgia plant is listed as related to the nightshade family and contains a dangerous alkaloid. McCoy, however, finds no trace of poison in the body, only red rings on the face and a total absence of salt.
The plant was placed there by the M-113 creature to hide its attack. Its name recalls the Borgias and their reputation as poisoners.