The abstract for the research paper cited in the BBC article, <i>The origin of Darwin’s “abominable mystery”</i> - American Journal of Botany - is at:<p><a href="https://bsapubs.onlinelibrary.wiley.com/doi/10.1002/ajb2.1592" rel="nofollow">https://bsapubs.onlinelibrary.wiley.com/doi/10.1002/ajb2.159...</a>