This tree is known as the Spirit of Vegetation, also called the Nascent Wood Seed, and these red fruits are none other than the renowned Zhu Fruits.
It's normal that no one recognizes the Zhu Fruits, as they are, essentially, not something that should exist on Earth.
According to what Li Xiaoyao knew, the Zhu Fruit is something originating from a higher plane of existence, such as The Third Realm.
As for the effects of the Zhu Fruit, they can be summarized in one sentence, "Comparable to Spirit Pills."
Li Xiaoyao was simply familiar with the Nascent Wood Seed plant but not so much with its preciousness.
Nevertheless, it would be a waste not to plunder such a heaven-sent treasure from The Third Realm that has suddenly appeared in the Secret Realm's sea area.
