And it can now be revealed that it was most likely ganoderma fungal decay that felled the legendary tree.

The jacaranda, which was planted in the south-eastern quadrangle of the sandstone university in 1928 and had a canopy that reached 18 metres wide, collapsed on Friday night.

As the student newspaper poetically opined: "It was found this morning, uprooted in the dew, while a string quartet played a soft melody for the white wedding that was set up on the adjacent grass."

While hundreds of tributes to the tree were being posted online over the weekend, its fallen remains were swiftly dismantled and removed.

The jacaranda has long marked the passing of time for university students, who created the legend that those who had not started studying before its first bloom would fail their exams.

Brett Summerell, director of science and conservation at the Royal Botanic Gardens in Sydney, said he conducted tests on the tree a few years ago and it was diagnosed with the fungal disease ganoderma. The disease is quite common, he said, and affects all kinds of trees.

"If the decay is out on a limb, you can cut the limb off and cut it back to health," Dr Summerell said.

"Looking at the way the [jacaranda] fell over and the work that has been done in the past, the decay is at the base of the tree so there's really nothing much you can do."

Dr Summerell said the fungus could take hold in trees through cracks in trunks or branches, including when twigs fall off. While the disease can have a productive function, causing hollows in trunks that serve as habitats for birds and animals, it can be hazardous when it strikes in an urban environment as it causes tree limbs to fall.

"You can see the decay happening, you know it is going to [fall], but you don't exactly know when," Dr Summerell said.

"Eventually it will rot away a tree so it falls over and dies as a result. That's just part of the natural cycle of regeneration in a forest situation."

While scattered purple flowers were all that remained of the tree after it had been removed from the quadrangle, Sydney University had taken cuttings of the tree in 2014 in order to graft them onto the base of other jacarandas.

"Grafted onto the base of other jacarandas, the cuttings have produced two clones," the university said in a statement. "This means that the university will be able to replace the jacaranda with genetically identical stock."

A University of Sydney spokeswoman said an official cause of death had not been determined, as arborists were still conducting investigations.