May 2019 Expedition to Honshu, Japan


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May 2019 Expedition to Honshu

In May of 2019, Michael Dosmann rejoined Utsunomiya University Professor Mineaki Aizawa and his graduate student Tatsuhiko Shibano, who hosted the Arnold Arboretum and colleagues on an expedition to Japan in 2018. The focus of this trip was Acer pycnanthum, a maple closely related to North America’s Acer rubrum and Acer saccharinum (red and silver maples, respectively). Like these two, A. pycnanthum sheds its ripened seeds in the spring, typically in May. Unlike the two American species, however, the Japanese tree is quite rare, with just 1500 trees left in the wild, occurring in central Honshu, and limited to acidic seeps.

The team visited several populations, documenting the trees’ habitat and condition, and collecting seed and herbarium vouchers. Because the species is just as rare in cultivation, the team collected amble seeds for propagation at the Arnold Arboretum as well as for distribution to numerous botanical gardens, arboreta, and germplasm repositories in the United States.