Based on an answer of mine from a few months ago, I've been inspired to adapt the concept to my own Life Ball. Fair warning- this question and some of its links are not for the squeamish. May contain graphic images and descriptions not suitable for all readers.
All is not rosy on this world, and there are plenty of thugs and assassins around just looking for creative ways to do-in an adversary. Fortunately, the local flora have provided a wonderful opportunity for a particularly gruesome and gory murder. It's risky - you have to initially get fairly close to the target, but you also have ample time to escape before the crime is discovered.
A certain member of the pinguicula genus- let's call it a vexwort- has become especially potent and hardy. It still prefers to spend its day trapping and absorbing insects, arachnids, and small reptiles and rodents. However, its mucilage is strong enough that any animal that brushes against one is likely to suffer a nasty rash, similar to that caused by giant hogweed exposure. It also has developed totipotency, allowing it re-grow an entire plant from a leaf segment as small as 2cm.
If one swallows such a segment of vexwort within a handful of hours of its cutting, it will re-grow from the inside out. Its own digestive secretions allow it to survive the acids of the stomach, and pass through. It then finds a convenient spot along the intestine and implants. It sends out new shoots through the soft tissues and begins soaking up all the victim's internal nutrients. Eventually, vexwort leaves burst out through the skin, by which time the victim has expired from multiple organ failure.
A would-be assassin needs to very carefully, with gloved hands, harvest a vexwort and cultivate it in a secret location until just before it is needed. He then needs to sneak one or more small cutting into the victim's soup or salad, just before it is eaten.
This is a "reality-check" question. Is this organism plausible and viable? What details of its life and development might I have overlooked, and need to think about more? One particular concern is over the cutting surviving being cooked and/or chewed.