Both cards are also Level 1 DARK-AttributePlant-Type monsters with similar ATK and DEF. They also have a similar appearance, have effects that involve leaving the Field and have mirrored poses of each other ("Evil Thorn"'s plant "fruit" is hanging to the right of the plant's stem, whereas "Necro Fleur"'s "fruit" is hanging to the left of its stem.)
This monster also resembles "Phoenixian Seed". Both it and this card are low level Plant-Type monsters capable of bringing out a specific stronger monster to the field when they are sent to the Graveyard.
Though "Fleur" means "flower" in French, ironically, this is the only "Plant" monster in the archetype.