Serenna veriformans (also called vermiform and veriforman) is a fictional plant that appears in the first novel and movie. There has never been reported a prehistoric fern genus named Serenna or a veriformans species. The word vermiform usually refers to something that is worm-like, like in Vermiform appendix In the movie the plant is not a fern but an angiosperm.
Jurassic Park novelEdit
In the first novel the endorsement team arrives at the pools of the Safari Lodge near the Visitor Center. Ed Regis points to the fact that the landscape of the park is planted with plants from the dinosaur age, like the Cyatheales (tree fern) Serenna veriformans near the pool.
This plant is nicknamed "Jurassic fern" by Ed Regis. However the plants were found abundantly in fossils more than 200 million years old, which is the Triassic period. Today it's common only in the wetlands of Brazil and Columbia.
This is shocking Ellie Sattler, she knows that the spores of this plant contain a toxic substance (beta-carboline alkaloid) that makes its fronds irritating to the skin and potentially deadly when eaten. The toxin was 50 times more poisonous than Oleander.
The fact that this dangerous plant is planted near a pool proves to Ellie that the creators of this Park hadn't done enough research before building it. It is also due to a more general lack of understanding of plants by the general public.
Jurassic Park film Edit
A different version of this plant appears in Jurassic Park. Upon arrival at Isla Nublar Ellie Sattler sees some plants (called vermiform in the script) and says they are supposed to be extinct since the Cretaceous period. InGen recreated this extinct plant.
Jurassic Park script quotes Edit
IN THE LEAD JEEP,
Ellie stares off to the right, fascinated by the thick tropical plant life around them. She tilts her head, as if something's wrong with this picture.
She reaches out and grabs hold of a leafy branch as they drive by, TEARING it from the tree.
IN THE FRONT JEEP,
Ellie stares at the leaf, amazed, running her hand lightly over it.
"Alan - -"
ELLIE (cont'd)(still staring at the leaf)
"This shouldn't be here."
ELLIE (cont'd) (still looking at the leaf)
"This species of vermiformwas been extinct since the cretaceous period. This thing - -" 
During the filming the taxa name has been changed from vermiform into veriforman, probably to make it closer to the name veriformans in the novel. It is clear that the leaf is not from a fern — it is a typical angiosperm (flowering plant) leaf. It also isn't poisonous, like its novel counterpart, because Ellie is running her hand lightly over it.
It is a bit counter-intuitive that InGen would recreate extinct plants and let them grow in the open fields and let tourists touch them. Moreover, there has never been described a plant taxa named ver(m)iform(an).
The leaf Ellie holds belongs to a species of veriforman. Indicating that “vermiforman” is the name of a genus or higher taxa. In which case, it should be written with a capital letter (which isn't the case in the subtitles or the script).
The word vermiform usually refers to something that is worm-like, like in Vermiform appendix, not really appropriate for the leaf Ellie holds. This could explain that the name vermiform was changed.
InGen not only recreated extinct animals, but also extinct plants. It is clear from the quote “this species of vermiform has been extinct since the cretaceous period” that this vermiform species was extinct. Furthermore, in the “lunch scene” Ellie refers to the fact that these ancient plants are back now and the dangers of that:
The question is: how much can you know about an extinct ecosystem, and, therefore, how could you assume you can control it? You have plants right here in this building, for example, that are poisonous. You picked them because they look pretty, but these are aggressive living things that have no idea what century they're living in and will defend themselves. Violently, if necessary.
Ancient DNA from plants could have been gained from leaf fragments or pollen in amber or from leaf slice that insects had sucked before they got trapped in amber. It is stated in the Lost World novel that InGen had a special facility for breeding plants for the park. Furthermore, recreating plants is much easier than recreating complex animals.