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 in-game depiction of smaller Erdtrees. However, the parallels run deeper.
Elden Ring lore suggests the Erdtree guides the souls of the departed, reflected by the catacombs at its base. Interestingly, Nuytsia floribunda holds similar spiritual significance in Australian Aboriginal culture. Each flowering branch represents a deceased soul, and its vibrant color is linked to the sunset, the believed destination of spirits.

Further strengthening the connection is Nuytsia's semi-parasitic nature; it draws nutrients from neighboring plants. This mirrors a popular fan theory positing the Erdtree as parasitic, having usurped the life force of an ancient Great Tree. However, game text referencing a "Great Tree" has been identified as a translation inaccuracy, actually referring to the Erdtree's own extensive root system.
Ultimately, whether FromSoftware intentionally drew inspiration from Nuytsia floribunda remains a mystery known only to the developers.