hayato fukuba , a senior official of the imperial household ministry and a doctor of agriculture (viscount ) who was also known as a horticulturist and landscape architect , was his adopted son . 園芸・造園家・宮中顧問官の 福羽逸人 農学博士（子爵）は、養嗣子にあたる。
doctor of agriculture , chozaburo tanaka advocated that origin of citrus unshu was nagashima , kagoshima prefecture (today ' s nagashima town , izumi district , kagoshima prefecture ) through literature research and field study , and as the estimated age of a tree 300-year-old was found in 1936 (withered away during the pacific war ), no doubt have influenced this theory . 農学博士の田中長三郎は文献調査および現地調査から鹿児島県長島（現鹿児島県出水郡長島町）がウンシュウミカンの原生地との説を唱え、1936年に当地で推定樹齢300年の古木（太平洋戦争中に枯死）が発見されたことからこの説で疑いないとされるようになった。
