How did I take this photograph? Very carefully. This Japanese honey locust is located near a rubbish bin, an attractant to the local population of yellow-jacket wasps. Since the bin is sealed, the wasps instead congregate on this tree – one landed on these pods a few seconds after taking this shot. Oddly, most of these 20cm (8in) long pods had been (or were being) chewed down by the wasps, particularly those pods in less exposed areas.
This is yet another one of those plants in which the scientific name has not been settled on. As you might suspect from the name koraiensis, this is the Korean morphological variety of the plant identified as distinct from the rest of the species by Nakai (it also grows in China and Japan). Authoritative taxonomic databases do not reflect Nakai’s interpretation, instead placing it strictly as the species Gleditsia japonica (and here).
In Phylogenetic relationships in Gleditsia (Leguminosae) based on ITS sequences (Am. J. Bot. 2003;90:310-320), Schnabel et al. are not able to provide a definitive answer as to whether the variety koraiensis should be recognized taxonomically, to wit:
“In addition, our two molecular data sets show different relationships among the G. japonica accessions. The cpDNA data suggest that the South Korean and Japanese accessions cluster separately from the Chinese accessions. In contrast, all the analyses of ITS data alone and the ML analysis of combined data place the South Korean accessions in one clade and the Japanese and Chinese accessions in a second clade. More extensive sampling of G. japonica, especially in China, will be necessary to determine whether any of the subspecific designations of G. japonica are phylogenetically justified and to clarify the taxonomic complexity of this group.”
It needs to be noted that clarifying the taxonomic complexity at this resolution was not the main goal of their work, as they were looking at Gleditsia more broadly.
Fortunately, acquiring more data for this species is achievable, as it is not threatened. Perhaps the name will be “finalized” one day. For now, I’ve used the varietal koraiensis, as it adds a tiny bit of information about this particular plant at UBC.
Nature resource link: I linked to it five months ago, but it’s worth mentioning again since there are so many new readers of BPotD – “Beauty and the Botanist”, an essay by the late Dr. Stan Rowe (full disclosure: his biography was written by my uncle). If you’ve ever wondered about BPotD’s tagline, “In science, beauty. In beauty, science. Daily”, this is the essay that serves as the inspiration.