[pc486]

As far as I understand it, this is a still debated question. One theory is it's about evaporating water: Plausible photomolecular effect leading to water evaporation exceeding the thermal limit (https://www.pnas.org/doi/10.1073/pnas.2312751120).

There are black plants though! And they're studied for the same kind of questions. E.g. The Functional Significance of Black-Pigmented Leaves: Photosynthesis, Photoprotection and Productivity in Ophiopogon planiscapus ‘Nigrescens’ (https://pmc.ncbi.nlm.nih.gov/articles/PMC3691134/)

[verisimi]

Nigrescens is overdue a 'naming review' with the Culture Ministry.