For better or worse, the modern Colosseum is a cleaned and sanitized version of its historic past. Gone are the plants that once made the building basically a big nursery. For hundreds of years, flowers, shrubs, and trees sprouted from the travertine and tuff walls. The first list appeared in 1643 and included 336 species, although this historic list does not correspond well with modern names. A study in 1815 dropped the number to 260 but then came Deakin, who appears to have combed every square foot of the Colosseum.
One of Deakin's 420. From Smithsonian Institution Library web site.
Filled with wonderful drawings, the book is also a delight to read. Like the best interpretive writing, Deakin delves into history and science, giving each plant a story, and something for the inquisitive botanist to discover. For example, said plant lover could find cures for dysentery, gout, and rheumatism, dine on strawberries, lettuce, onions, and asparagus, and alleviate the effects of “too great potations” of wine. If you are interested in testing Deakin’s hangover cure, all you have to do is find some Hedera helix, better known as English ivy.
Alas, archaeologists in the 1870s recognized how damaging plants were to the structure and stripped the green mantle. Diversity also decreased with the loss of grazing animals and their contributions to soil fertility. Not all plants have fared poorly in modern times: the most recent floristic study, conducted in 2002, reported that alien species, particularly those associated with humans, have flourished. The 2002 study described 242 species, and total diversity for all studies is 684 species.
Although I understand why workers in Rome remove the plants, I wish they didn’t have to. At least the plants grow fast enough that I can still see this wonderful link between geology and botany.