From the Field Notes of Colonel Aubrey Fitch-Harrington, FRS

Observations Upon the Fauna of Southern Africa — Volume III (In Preparation)

“The Fever Tree (Vachellia xanthophloea) is named for the disease it was believed to cause. It did not cause the disease. Early settlers noticed that malaria appeared wherever fever trees grew and named the tree accordingly. Malaria is caused by Plasmodium parasites transmitted by Anopheles mosquitoes, which bred in the waterlogged ground that fever trees prefer. The disease followed the tree’s preferred habitat. The settlers watched the sequence and named the innocent party. The author has been sitting under the fever tree since the first camp in this volume. He has written camp table notes beneath it, drunk tea beneath it, conducted his morning survey past it, and referred to it in twelve separate field entries as ‘the fever tree, camp vicinity.’ The name is three hundred years old. It has never been correct. The author notes that this places it in the good company of several other three-hundred-year-old names he has been using.”

He had been calling it the fever tree since the first volume.

Everyone called it the fever tree. The name was in the field guides, on the reserve maps, in the camp information booklet. The fever tree. The yellow-green bark that was its most distinctive feature, the specific luminous quality it had in morning light, the fever it caused.

He was sitting under one at the camp table, which was where he had been sitting for two volumes, and he had just read the fever’s actual cause.

Not the tree.

The yellow-green bark was produced by chlorophyll — the tree photosynthesising through its bark as well as its leaves. That was the colour. That was the luminosity. It was not jaundice. It was not a disease marker. It was a tree solving the problem of energy production through every available surface, including the bark, which most trees did not.

“The name,” Cetshwayo said, appearing with the morning tea.

“The name is wrong.”

“The name is old.”

“Three hundred years.”

“Yes.”

The Colonel looked at the bark. Green-gold in the morning light, the specific luminosity the Colonel had been noting as significant without identifying as photosynthesis. The mosquitoes had bred in the waterlogged ground where the fever tree preferred to grow, and the disease had followed the tree’s preferred habitat, and the settlers had watched the sequence and named the innocent party, and the name had stood for three hundred years.

He wrote: The fever tree did not cause fever. It grew where the mosquitoes that caused fever also lived, because both preferred waterlogged ground near water. Three hundred years of innocent association with the wrong name. The author has been calling it the fever tree for two volumes. He will continue calling it the fever tree because that is the name and names do not correct themselves simply because the naming was wrong. He notes that this is also true of several entries in his own field notes, which have been running on similar principles.

He drank his tea under the tree that did not cause fever.

He counted the entries. Twelve. Twelve field notes in this volume alone that referred to the fever tree, camp vicinity as though the name required no further examination. The name was three hundred years old and the Colonel had been adding to its tenure for two volumes without once questioning it.

The morning was ordinary and correct. The bark was luminous because it was photosynthesising, not because it was diseased. The Colonel picked up his notes and carried them inside and wrote the correction in the margin of all twelve entries, which took some time but which seemed, under the circumstances, the least he could do.