Reddit user Independent-Design17 proposed a fascinating connection between Elden Ring's Erdtree and the Australian Christmas tree, Nuytsia floribunda. Superficial similarities exist, particularly when comparing the game's smaller Erdtrees to the Nuytsia. However, the parallels run deeper.
Elden Ring lore positions the Erdtree as a guide for the souls of the departed, explaining the catacombs at its base. Interestingly, Aboriginal Australian culture views Nuytsia as a "spirit tree," with each flowering branch representing a deceased soul, and its vibrant colors linked to the sunset, the supposed destination of spirits.
Further bolstering the theory is Nuytsia's semi-parasitic nature; it thrives by drawing nutrients from surrounding plants. This resonates with fan theories suggesting the Erdtree is parasitic, having allegedly usurped the life force of an ancient Great Tree. However, game text referencing a "Great Tree" is now understood to be a mistranslation, actually referring to the Erdtree's own extensive root system.
Ultimately, whether FromSoftware intentionally drew inspiration from Nuytsia remains a mystery known only to the developers.