Step 1: Understanding the Concept:
In the early days of Indian archaeology, European scholars often interpreted Buddhist art based on their own cultural frameworks rather than local religious texts.
Step 2: Detailed Explanation:
James Fergusson was an influential architectural historian in the $19^{th}$ century.
In 1868, he published a work titled "Tree and Serpent Worship" which focused on the sculptures at Sanchi and Amravati.
He saw frequent depictions of the Bodhi tree and snakes (Nagas) in the stone carvings.
Lacking a deep understanding of Buddhist hagiography and symbolism, he concluded that the site was a center of primitive nature worship involving trees and serpents.
He did not realize that the tree symbolized the Buddha’s enlightenment and the Nagas were protective deities in Buddhist lore.
Step 3: Final Answer:
The scholar was James Fergusson.